Reflectometer-based remote location identifier and condition monitor for power grids

Abstract

A system is configured to monitor an electric powerline and includes a sensor configured to acquire a reflectometry data through the electrical cable. The system also includes an impedance modifier positioned on or adjacent to the electrical cable at a location along the electrical cable, the impedance modifier configured to cause a reflectometry signal response at the location. The system also includes a switch configured to selectively bypass the impedance modifier.

Description

REFLECTOMETER-BASED REMOTE LOCATION IDENTIFIER AND CONDITION MONITOR FOR POWER GRIDS

[0001] This application claims the benefit of US Provisional Patent Application No. 63 / 718,201, filed 8 November 2024, the entire contents of which are incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure relates to the field of electrical equipment, including power cables and accessories, e.g., for power utilities and industrial and commercial sites.BACKGROUND

[0003] Electrical power grids include numerous components that operate in diverse locations and conditions, such as above ground, underground, cold weather climates, and / or hot weather climates. When a power grid suffers a failure, it can sometimes be difficult to determine the cause of the failure. Sensor systems for power networks, especially underground power networks, are increasingly becoming employed to detect grid anomalies (such as faults or precursors of faults) so that an operator can react more quickly, effectively, and safely to maintain service or return the system to service.Examples of sensor systems include faulted-circuit indicators, reverse-flow monitors, and power-quality monitors,SUMMARY

[0004] In general, the present disclosure describes systems and techniques for monitoring an electric power grid, e.g., for identifying a location along an electrical cable (e.g., a power cable) and / or other equipment, and / or evaluating a condition of electrical cables and / or other electrical equipment. The systems described herein include a reflectometry sensor, e.g., a frequency domain reflectometry (FDR) sensor or a time domain reflectometry (TDR) sensor, and a marker including an impedance modifier configured to change an impedance of the electrical cable at a location along the electrical cable. In some examples, the marker may include a switch configured to selectively bypass the impedance modifier, e.g., to control changing the impedance of the electoral cable at the location by sel ectively bypassing, or not, the impedance modifier of the marker.

[0005] In some aspects of this disclosure, a system including a reflectometry sensor and a marker may be configured to identify a location along the electrical cable. For example, the sensor may be configured to inject a signal onto the electrical cable (e.g., a FDR or TDR signal) and acquire reflectometry data indicative of electrical responses of various entities at various locations along the electrical cable, e.g., entities that may cause a local impedance change (and this a signal reflection) such as nodes, splices, defects and / or local conditions of the electrical power cable, or any suitable entity that may cause an impedance change and signal reflection. The marker may selectively cause an impedance change and reflectometry signal response (e.g., signal reflection) at the location where the marker is on or adjacent to the electrical cable, and the sensor may acquire reflectometry data including the reflectometry signal response, which is indicative of the location of the marker.

[0006] In some examples, the impedance change caused by the impedance modifier of the marker may cause a plurality of reflectometry signal responses, e.g., by other entities along the electrical cable. For example, the parallel (bypass) marker switch may be selectively controlled to be open, thereby not allowing the injected reflectometry signal to bypass the impedance modifier, or to be closed to allow the injected reflectometry signal to bypass the impedance modifier (e.g., the marker is “off”). In some examples, the switch may be normally open and selectively controlled to close to bypass the impedance modifier, and in other examples the switch may be normally closed and selectively controlled to open to not bypass the impedance modifier, in the open (e.g., “on”) position, the impedance modification by the impedance modifier of the marker may cause a change in the reflectometry signal at the marker location and also cause changes to reflectometry signal responses by other entities along the line, e.g., the marker may cause its own reflectometry response and affect the reflectometry responses of oilier entities along the line at other locations. Hie locations of the other entities may then be identified based on a difference in their respective reflectometry' responses when the marker is “on” (e.g., the switch does not cause the reflectometry signal to bypass the impedance modifier) or “off” (e.g., the switch does cause the reflectometry signal to bypass the impedance modifier). For example, whether certain entities are along the same branch of the electrical cable as the marker may be determined based on their corresponding reflectometry' signal response differences (or lack thereof) when the marker is on versus off.

[0007] In some aspects of this disclosure, a system including a reflectometry sensor and a marker may be configured to identify a condition of the electrical cable or of a component coupled to the electrical cable, e.g., a node, a splice, or any other suitable electrical cable component. For example, the switch of the marker may be configured to selectively bypass the impedance modifier based on a condition. The condition may be a temperature (e.g., of the switch, which may be indicative of a temperature of the electrical cable and / or component of the electrical cable ), a temperature range, a humidity or humidity range, a water ingress, or any suitable condition. The marker may then cause, or not cause, a reflectometry signal response that may be acquired by the sensor, based on the condition.[00081 In one example, this disclosure describes a system configured to monitor an electric powerline, the system including: a sensor configured to acquire a reflectometry data through the electrical cable; an impedance modifier positioned on or adjacent to the electrical cable at a location along the electrical cable, the impedance modifier configured to cause a reflectometry signal response at the location; and a switch configured to selectively bypass the impedance modifier.

[0009] In another example, this disclosure describes a marker of an electric powerline including an electrical cable, the marker including: an impedance modifier positioned on or adjacent to the electrical cable at a location along the electrical cable, the impedance modifier configured to cause a reflectometry signal response at the location; and a switch configured to selectively bypass the impedance modifier.

[0010] In another example, this disclosure describes a method including: injecting, by a sensor, a reflectometry signal onto an electrical cable of an electrical powerline; causing, based on a first condition, a switch to selectively bypass an impedance modifier positioned on or adjacent to the electrical cable at a location along the electrical cable, the impedance modifier configured to cause a reflectometry signal response at the location; acquiring, by the sensor, reflectometry data indicative of the reflectometry signal response; and determining, by processing circuitry and based on the reflectometry data, the condition.

[0011] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description, drawings, and claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. l is a conceptual diagram illustrating an example power-cable construction.[0013J FIG. 2 is a conceptual diagram illustrating another example power-cable construction.

[0014] FIG, 3 is a conceptual block diagram of an example electrical power network including primary and secondary monitoring nodes.

[0015] FIG. 4 is a block diagram illustrating an example arrangement of sub-components of a monitoring node including a reflectometry sensor.

[0016] FIG. 5 is a block diagram illustrating an example configuration for a monitoring node electrically coupled to a power-delivery system via a removable T-body connector.

[0017] FIG. 6 is a schematic diagram of example implementations, or deployments, of a reflectometry' sensor and marker on an electrical power network or grid.

[0018] FIG. 7 is a schematic diagram of an example implementation, or deployment, of a reflectometry sensor and marker including a ferrite bead and a switch on an electrical power network or grid.

[0019] FIG. 8 is a schematic cross-sectional diagram of a splice illustrating an example arrangement of a marker.

[0020] FIG. 9 is a schematic cross-sectional diagram of a splice illustrating an example arrangement of a plurality’ of markers,

[0021] FIG. 10 is a schematic cross-sectional diagram of a splice illustrating another example arrangement of a plurality of markers.

[0022] FIG. 11 is a schematic cross-sectional diagram of a splice illustrating another example arrangement of a plurality of markers.

[0023] FIG. 12 is a schematic cross-sectional diagram of a splice illustrating another example arrangement of a marker.

[0024] FIG. 13 is a schematic cross-sectional diagram of a splice illustrating another example arrangement of a marker.

[0025] FIG. 14 is a conceptual block diagram of another example electrical power network including a reflectometry sensor and marker and including a plurality of branched segments of the electrical power network,

[0026] FIG. 15 is a flowchart illustrating example method of monitoring an electric power network.

[0027] It is to be understood that the embodiments may be utilized, and structural changes may be made without departing from the scope of the invention. The figures are not necessarily to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number,DETAILED DESCRIPTION

[0028] Examples of the present disclosure include devices, techniques, and systems for monitoring an electric powerline including and electrical cable, e.g., a powerline of power grid. Medium and high voltage (MV, HV) power distribution systems may suffer failure due to the interaction of the electrical stress with pre-existing or emerging structural defects in cables, cable accessories, and other equipment. These failures may be unexpected and may result in worker and public safety risks, loss of production and revenue, liability', reduced reliability metrics, and cascading failures due to overload of the remaining system. Avoidance of failure is often desired, but if the failure location can be identified quickly then the operator can repair it in a planned process thereby minimizing some of the negative impacts. An on-line continuous monitoring of the distribution system to detect and locate failure locations and to detect and locate pre-fault defects (preexisting and new structural defects that are at risk of imminent failure) may be advantageous. Widespread deployment of such a system may provide a reduction in the time required to repair a cable sy stem failure (fault) and allow the operator to address and correct equipment issues and avoid failures altogether.[0029J Powerlines may transmit electrical power from a power source (e.g., a power plant) to a power consumer, such as a business or home. Powerlines may be underground, underwater, or suspended overhead (e.g., from wooden poles, metal structures, etc.). Powerlines may be used for electrical-power transmission at relatively high voltages (e.g., compared to electrical cables utilized within a home, which may transmit electrical power between approximately 12 volts and approximately 240 volts depending on application and geographic region). For example, powerlines may transmit electrical power above approximately 600 volts (e.g., between approximately 600 volts and approximately 1,000 volts). However, it should be understood that powerlines may transmit electrical power over any voltage and / or frequency range. For example, powerlines may transmit electricalpower within different voltage ranges. In some examples, a first type of powerline may transmit voltages of more than approximately 1,000 volts, such as for distributing power between a residential or small commercial customer and a power source (e.g., power utility). As another example, a second type of powerline may transmit voltages between approximately IkV and approximately 69kV, such as for distributing power to urban and rural communities. A third type of powerline may transmit voltages greater than approximately 69k V, such as for sub-transmission and transmission of bulk quantities of electric power and connection to very large consumers.

[0030] In accordance with aspects of this disclosure, a system includes a sensor configured to acquire reflectometry data, e.g., frequency domain reflectometry (FDR) data and / or time domain reflectometry (TDR) data, through an electrical cable, and a marker configured to selectively modify the reflectometry signal. The sensor may also be configured to inject a reflectometry signal on, or onto, the electric powerline and electrical cable. The marker may include an impedance modifier positioned on or adjacent to the electrical cable at a location along the electrical cable, and the impedance modifier may be configured to cause a reflectometry’ signal response at the location. The marker may also include a switch configured to selectively bypass the impedance modifier.

[0031] The marker may be configured to mark the location, e.g., cause a reflectometry signal response indicative of the location of the marker along a power cable, or cause a reflectometry signal response, or a change in a reflectometry' signal response, of other components along the powerline, e.g., nodes, splices, junctions, thereby indicating the locations of the other components. For example, an impedance modifier may7cause a change in the reflectometry' signal upstream or downstream from the marker, there by causing a change in the reflectometry' signal responses of components ups tream or downstream from the marker, the changes being indicative of the locations of the respective components. The marker may be configured to mark a condition of the powerline at the location. For example, the marker may include a switch configured to selectively bypass the impedance modifier based on a condition of the cable and / or a component (e.g., node, splice, junction, or the like) connected to the cable. The marker may then identify one or more conditions of the power distribution grid based on the presence or absence of a reflectometry' signal response at that location due to the switch selectively bypassing the impedance modifier or not. The one or more conditions mayinclude defect types, locations, and / or severity, grid and / or component health, location, performance and / or capability of the grid and / or components of the grid. In some examples, the marker may be configured to mark a power cable. For example, the marker may be attached to a power cable to cause a reflectometry signal response indicative of tire power cable, e.g., the marker may be used to identify a particular power cable of a plurality of power cables.

[0032] In some examples, powerlines may include electrical cables and one or more electrical cable accessories. For example, FIGS. 1 and 2 depict two example electricalpower cables 100A and I00B (collectively, “cables 100,” or, in the alternative, “cable 100”), respectively. Po 'er cable 100A is an example of a “single phase” MV cable, e.g., having only a single central conductor 112. Power cable 100A includes jacket or oversheath 102, metal sheath or cable shield 104, insulation screen 106, insulation 108, conductor screen 110, and central conductor 112. Power cable 100B is an example of a three-phase extruded medium-voltage (MV) cable, e.g., having three central conductors 112A-112C (collectively, “conductors 112,” or, in the alternative, “conductor 112”). Polyphase cables like cable 100B can cany’ more than one shielded-conductor 112 within a single jacket 102. Other examples of typical, but not depicted, cable layers include swellable or water-blocking materials that are placed within the conductor strands 114 (“strand fill”), or between various other layers of the cable 100 (“filler 116”).

[0033] Example cable accessories may include splices, separable connectors, terminations, and connectors, among others. In some examples, cable accessories may include cable splices configured to physically and conductively couple two or more cables 100. For example, a cable accessory’ can physically and conductively couple cable 100A or cable 100B to other electrical cables. In some examples, terminations may be configured to physically and conductively couple a cable 100 to additional electrical equipment, such as a transformer, switch gear, power substation, business, home, or other structure.

[0034] Electrical cables 100 and cable accessories can be assembled into an electrical power network, or in some specific examples thereof, an electrical pow er grid, to distribute electrical power to various consumers or other end-users. For instance, FIG. 3 is a conceptual block diagram depicting a first example electrical power network 200. For instance, pow'er network 200 includes at least two power-transmission lines or “feeder” lines 202A, 202B (collectively, “feeder lines 202”), which may be examples of powercables 100 of FIGS. 1 and 2. Distributed along feeder lines 202, power network 200 includes one or more substation buses 204, circuit breakers 206, automatic circuit reclosers (ACRs) 208, sectionalizers 210, electrical switches 212 (e.g., with voltage transformers), and / or other cable accessories.

[0035] In some examples, power network 200 includes a monitoring system 214 configured to collect and process data indicative of one or more conditions of the power network. As described herein, monitoring system 214 includes a central computing system 220, and at least one monitoring node 222 operatively coupled to feeder lines 202. In some examples, power network 200A may include at least one “secondary” monitoring node (not shown) operatively coupled to feeder lines 202 at some distance away from the monitoring nodes 222, e.g., greater than about 5 meters away from a monitoring node 222, or greater than 10 meters away, or greater than 25 meters away, or greater than 50 meters away, or greater than 100 meters away, or greater than 500 meters away, or greater than 1 kilometer away, or greater than 5 kilometers away, or greater than 10 kilometers away.

[0036] As detailed further below, monitoring nodes 222 may include one or more monitors, sensors, communication devices, and / or one or more power-harvesting devices, which may be operatively coupled to insulation screen 106 (FIG. 1 and FIG. 2) of the cable 202 to perform a variety of functions. The one or more sensors (e.g., monitors) can output sensor data indicative of conditions of the cable 202 or a proximate cable accessory. Examples of such sensors include reflectometers, temperature sensors, partialdischarge (PD) sensors, smoke sensors, gas sensors, and acoustic sensors, among others.

[0037] According to further aspects of this disclosure, computing system 220, such as a remote computing system and / or a computing device integrated with one or more of monitoring nodes 222, may comprise processing circuitry configured to receive reflectometry data acquired by a reflectometry sensor and process the reflectometry data, e.g., reflectometr' data that may include one or more reflectometry signal responses of one or more marker (e.g., markers 802, 1302, 1402 of FIG S. 6-13). For example, the processing circuitry of computing system 220 may be configured to determine the location along cable 100 and / or the amount of impedance change based on the reflectometry' data. The processing circuitry of computing system 220 may be configured to determine the existence and / or amount of one or more conditions (e.g., temperature, temperature change, humidity, water ingress or submersion, one or more defects, or the like) based on thereflectometry data including one or more reflectometry signal responses,

[0038] As indicated by dashed lines 226 in FIG, 3, each monitoring node 222 includes a direct data connection with central computing system 220. For instance, each monitoring node 222 may communicate data with central computing system 220 via any or all of a wireless data communication, a mesh network, an Ethernet network, fiber optic cables, or a direct electrical integration (e.g., common electrical circuitry) with central computing system 220.

[0039] FIG. 4 is a block diagram illustrating an example arrangement of sub-components of moni toring node 522 including a reflectometry sensor, where the arrangement of subcomponents is configured to electrically couple a set of “functional” sub-components 502 to an article of electrical equipment 504 of a power-delivery system. Monitoring node 522 may be an example of monitoring nodes 222 which may be used with electrical power network 200 of FIG, 3.

[0040] As shown in FIG. 4, the functional sub-components 502 of monitoring node 522 include one or more of a voltage-sensing unit 506, a data-acquisition unit 508, a data-processing-and-storage unit 510 (e.g., processing circuitry), a “secondary” communication unit 512, and a capacitive-power-harvesting-and-power-management (CPIIPM) unit 514. The functional sub-components 502 are generally configured to receive and process signals generated by various sensors of monitoring node 522. As shown in FIG. 4, these various sensors may include one or more of reflectometry sensor 516, ground sensors, electrical -current sensors, environmental sensors, or other sensors.

[0041] In some examples, the functional sub-components 502 (and / or other adjacent devices 526) may additionally receive electrical power from other power harvesters 528, e.g., other than via a coupling to a component 504 of the power network. For instance, as shown in FIG. 4, monitoring node 522 includes a high-voltage capacitive coupling unit 530, which may include high voltage capacitors 532, low voltage capacitors 534, and low voltage connection 536, and which may be configured to electrically couple the functional sub-components 502.

[0042] In some examples, monitoring node 522 is removably coupled to a component 504 of an electric-power network via a separable T-body connector 540. As shown in FIG. 4, T-body connector 540 includes three ports configured to mutually electrically couple (1) a pow er cable 100 of an electric powerline; (2) an article of electrical equipment 504, suchas a cable splice, cable termination, etc,; and (3) monitoring node 522. T-body connector 540 further includes a ground connection 542 to an electrical ground 544, e.g., of electrical equipment 504. In some examples, monitoring node 522 may be removably coupled via a different connector from a T-body connector, e.g., tire connector may be a removable elbow-type connector, alive fronttermination, an insulating plug, or the like.

[0043] FIG. 5 is a block diagram illustrating an example configuration for a monitoring node 622 electrically coupled to a power-delivery system via a removable T-body connector 540. Monitoring node 622 may be an example of monitoring node 522 of FIG.4, except for the differences noted herein.

[0044] In the example shown in FIG. 5, an arrangement of sub-components is configured to electrically couple a set of “fiinctional'’ sub-components 602 to an article of electrical equipment 504 of a power-delivery system. As shown in FIG. 5, the fiinctional subcomponents 602 of monitoring node 622 include one or more of a communication unit 612, a data analysis unit 610, a current and / or voltage -sensing unit 606, a data-processing-and-storage unit 510 (e.g., processing circuitry), a partial discharge (PD) unit 608, a reflectometry sensor 616, and a capacitive-power-harvesting -and-power-management (CPIIPM) unit 614. The functional sub-components 602 are generally configured to receive and process signals generated by various sensors of monitoring node 622. As shown in FIG. 5, these various sensors may include one or more of inductive couplers 1036 and 1038, electrical-current sensors, environmental sensors, or other sensors.

[0045] In the example shown in FIG. 5, communication unit 612 may be configured to communicatively couple monitoring node 622 to electrical equipment 504 and / or cable 100, e.g., to communicatively couple sub-components 602 to the powerline. Data analysis unit 610 may be substantially similar to data acquisition unit 508 and data processing and storage unit 510 described above. Partial discharge unit 608 may be configured to sense partial discharge signals, and power harvesting unit 614 may be substantially similar to power harvesting unit 514 described above.

[0046] In some examples, monitoring node 622 is coupled to the power line at a termination point (e.g., with one or three phases per device) through capacitive coupling and contains various sensing capabilities, such as power harvesting, e.g,, via power harvesting unit 614. Other sensing and functionality at this device can be included such as environmental sensing (temperature, humidity, gas) or functions to help locate a cable or adefect in the cable or other equipment.

[0047] In the example shown in FIG. 5, multiple sensing modes include reflectometry- via reflectometry sensor 616. e.g., FDR and / or TDR, partial discharge via partial discharge unit 608, voltage and current monitoring, via current / voltage monitoring unit 606, and other sensing modes, e.g,, temperature, humidity, gas, and the like. The multiple sensing modes may be complementary and may be used to monitor different types of defects substantially concurrently and to increase an accuracy in locating and / or gauging condition, defect, or event severity relative to sensing a single sensing mode. In some examples, reflectometry'- sensor 616 may be used in conjunction with a marker including an impedance modifier and a switch configured to selectively bypass the impedance modifier, tire marker located at monitoring node 622 or at another location separate from monitoring node 622, e.g,, another monitoring node, a splice, a junction, or at any position along cable 100.

[0048] In some examples, monitoring node 622 may be configured to acquire reflectometry' data by injecting a reflectometry' signal comprising a sweep of frequencies into a cable and / or the grid at a location, and then acquire (e.g., sense, measure, detect) one or more reflectometry' signal responses, e.g., one or more reflected signals.Reflectometry' sensor 616 may be configured to map any impedance changes along the “probed” portion of the powerline. For example, impedance changes may occur with changes in the cable geometry' or insulating materials properties (such as water in the insulation), or may be selectively caused to occur, e.g., via a marker comprising an impedance modifier and switch configured to selectively bypass the impedance modifier. Reflectometry' sensor 616 may be configured to acquire multiple reflectometry- signal scans over time, and the causes of impedance changes may be detected and located. In some examples, reflectometry' sensor 616 may be configured to acquire sensor data indicative of defects such as broken or damaged neutrals, open conductors, shunt faults and / or other structural changes in the powerline cable via reflectometry', e.g., FDR and / or TDR. In some examples, such defects may cause a switch of a marker may be configured to selectively' bypass an impedance modifier of the marker, e.g., based on the occurrence, or non-occurrence, of the defect(s).

[0049] In the example shown in FIG. 5, several of the sensing modalities (e.g., current, voltage, PD, reflectometry) interface with the power system through an electrical couplingand / or interface, such as a capacitive electrical connection or one or more inductive couplings, at a cable termination via monitoring node 622. This provides a common and available interface in most distribution systems and supports the multiple functions with a single (or combined) physical interface. In the example shown, inductive coupler 1036 may be a Rogowski coil for sensing a powerline current, and inductive coupler 1038 may be a high frequency current transformer (HFCT) for sensing partial discharge on ground connection 542, e.g., as an alternative to sensing a partial discharge to a capacitive electrical connection, or to additionally sense a partial discharge.

[0050] In some examples, coupling sensors to a power grid with the fewest components (e.g., monitoring nodes) for the full functionality is advantageous for total cost reduction, streamlined installation, and ease of maintenance. These types of terminations may be located at transformers and switchgear in the grid and may be utilized for the monitoring system. In some examples, magnetic coupling techniques may be used, including a ferrite bead and / or HFCT. In some examples, capacitive coupling techniques may be used, including single or multiple capacitors in parallel at a cable termination location within the equipment at the connection point (e.g., a bushing), or integrated with a live front termination.

[0051] Medium and high voltage (MV, HV) power distribution systems may be prone to failure due to the interaction of electrical stress with pre-existing or emerging structural defects in cables, cable accessories, and other equipment. These failures may be unexpected and may result in worker and public safety risks, loss of production and revenue, liability, reduced reliability metrics, and cascading failures due to overload of the remaining system. Avoidance of such failure is desirable, but if the failure location(s) may be identified quickly then an operator can repair the failure(s) in a planned process thereby-reducing some of the negative impacts. It may be advantageous to implement on-line continuous monitoring of the distribution system to detect and locate failure locations and to detect and locate pre-fault defects (pre-existing and new structural defects that are at risk of imminent failure). Widespread deployment of this system may provide a reduction in the time required to repair a cable system failure (fault) and allow the operator to address and correct equipment issues and avoid failures altogether.

[0052] In some examples, a system according to this disclosure can be deployed on-line (an energized system) in medium voltage distribution systems to effectively monitor thedistribution equipment (cable system and other equipment like transformers and switchgear) for pre-existing and emerging structural defects. Example systems, devices, and techniques may implement frequency domain reflectometry (FDR) and / or time domain reflectometry (TDR) simply and cost-effectively on the network by monitoring at one or more locations, and marking at one or more locations. In some examples, a reflectometry sensor may be located at a specific point, location, and / or position, and marker may be located at the same, or different, specific point, location, and / or position.

[0053] In some examples, the measurement may also depend on knowing the velocity of propagation in the cable, which may be dependent on factors such as the effective dielectric constant of the cable or cables. In some examples, if a reflectometry sensor at a known location is used in combination with a marker, including a selectively enabled / disabled impedance modifier, at another known location, then the velocity of propagation may be accurately determined. Because the defect location is critical for repair operations, the system can therefore benefit from a reflectometry sensor and marker used to monitor the powerline and / or equipment.

[0054] It is often desirable to identify the location of a cable fault so that the cable can repaired and returned to sendee quickly. Hie techniques disclosed herein provide methods and systems to identify impedance changes along a distribution system (e.g., an electrical distribution system, a powerline, power grid, high, medium, or low voltage powerline, or the like) and the connected equipment. Other applications of the techniques and systems disclosed herein may include, but are not limited to: fault identification and location determination due to changes in the cable structure because of the event (e.g., a comparison of the pre- and post-failure impedance information or post-failure alone, which may be indicative of damage to the shield, insulator, conductor, connector and lugs, cable accessory, or the interface between the cable accessory and the cable), fault identification and location determination due to lower impedance during the fault event, transformer health including the potential for finding water ingress and winding defects, switch position, mechanical damage to cable or accessory shielding, damage and opening of a cable or accessory jacket, damage to the cable and accessory insulation, water ingress in the cable or accessories (e.g,, uniform water absorption and water trees), changes in the grid topology and layout, determining the propagation delay along a given cable, determining and monitor the propagation characteristics of the cable across a frequencyband (e.g., including frequency dependence and propagation speed), determining the impedance of a cable or cable section, localized elevated temperature along the cable from connector or conductor overheating or from a temporary event (e.g., an arc), mapping grid elements and topology by the characteristics of the local reflectometry data fingerprint, identifying grid cable types and conditions based on small fluctuations of impedance along the cables, and identifying the type and condition of elements in the grid based on their reflectometry data fingerprint and temperature dependence.

[0055] lire methods, devices, and systems described herein may be used to identify the location or distance to specific areas of impedance change. The methods, devices, and systems described herein include a system and method including a reflectometry sensor and marker each coupled to an energized line through interface (e.g., a galvanic interface, a magnetic interface, an inductive interface, a capacitive interface), and detection of conditions (e.g., temperature, humidity, water ingress, or the like) of the energized line, e.g., power cable.

[0056] In some examples, when a cable fault occurs, the powerline may have a short (shunt) circuit or an open circuit (break) in the conductor or the metallic shield. In both cases, the fault manifests as an abrupt change in the line impedance - zero impedance in the case of a short, and infinite impedance in the case of a break. This abrupt impedance change may cause any signal that is traveling along the line to reflect back to its source, with the reflection coefficient depending on the nature of the impedance change.

[0057] One method to locate a fault is time domain reflectometry (TDR). In a TDR method, a short electrical pulse is injected into one end of a line and a reflection from a fault is detected. The time delay between the injected and reflected pulse is just twice the travel time to the fault. If the speed of propagation in the line is known, this directly translates to a distance.

[0058] Another method to locate a fault is frequency domain reflectometry (FDR).Example frequency domain methods may include Line Resonance Analysis (LIRA) methods. For example, a broadband signal may be injected into the line, and the resulting signal is received. In some examples, a voltage may be injected into the line and the resulting current may be recorded using a current sensor. From the recorded signal, the frequency-dependent complex impedance Z(f) may be calculated. In the presence of a reflection, the impedance may oscillate in a (pseudo) periodic manner as the frequencychanges. For example, the impedance may comprise peaks in the impedance, with the separation between the peaks corresponding to Af =vd*w^iere’vis the speed of propagation, d the distance to the fault, and Af is a frequency change or the bandwidth of the injected broadband signal.

[0059] An underground cable may be coaxial, and at high enough frequencies the underground coaxial cable may be regarded as a transmission line. Such a line may be described by defining the capacitance C, inductance L, resistance R (zero for an ideal line) and conductance G (zero for an ideal line) per unit length. The voltage and current on an infinitesimal section of cable may then satisfy the set of partial differential equations known as the telegrapher’s equations:

[0060] For each angular frequency co, assuming relatively low loss, the line supports traveling-waves of the form of Equation (2):

[0061] The solutions are right-and-left propagating waves. If the amplitude of the outgoing wave is Av and that of the incoming wave is B.. one can show that the effective impedance of the line will be:Z = Z0^, Zo= £ (3)where Zo is known as the characteristic impedance of a line, and for underground MV lines it is usually between 25-40 Q.

[0062] The waves have to satisfy the boundary' conditions on both ends of the cable. For example, if the cable is open at its far side the current should vanish there, while a short circuit manifests as the vanishing of the voltage. In general, if the line is terminated by an impedance ZO*ZT, the impedance measured at the end of a line of length X will be:

[0063] For the open circuit case, ZT= co, and so:

[0064] For a short circuit, ZT= 0, giving:

[0065] In both cases, for small loss coefficient a, the impedance is pseudo-periodic, with period A / c ~or A =Cj^X’ ^1US^1Cfarther away is the open or short circuit, the closer apart will be the peaks of the impedance.

[0066] A simple manipulation may be performed to give us a simpler result. For example:

[0067] And therefore:2Z0[Z - Z ”1- 1 = r~1exp —2jkrX + 2aX) (8)

[0068] Expression (4) above may be useful for the case of an impedance measurement performed on one side of a line. However, in many cases the measurement may be performed in the middle of a line. In such a case the impedance comprises the left and right cable impedances connected in parallel to each other. A similar case applies if there are several lines running in parallel, for example in a high current branch. Similarly, if the device is placed on a transformer, there may be coupling of all three phases through the transformer impedance (which at high frequencies is typically a capacitance).

[0069] For simplicity, consider the case of two cables connected in parallel, with finite lengths Xi, 2 respectively. Since the lines are in parallel, their admittances will add up:

[0070] In such a case, a technique based on Equation (8) may not work. Instead, Equation (9) is a sum of two terms, each of which has multiple (complex) poles at the points where its respective denominator vanishes:rnexp(2 / / crXn- 2aXln) = 1 (10)

[0071] Consequently, the poles of / comprise the poles of both line segments. Note that this is not the case for the poles of the impedance, since the zeros of F (which are the poles of Z) do not add up in a simple manner.

[0072] An alternative to TDR is FDR. This technique arises from the observation that the high-bandwidth pulse used in TDR can be decomposed into a series of complex exponentials via a Fourier transform. Since the system under investigation is linear, one can then replace the pulse with a suitably weighted narrowband excitations, which are then recombined to yield the same result one would receive from the TDR pulse.

[0073] In some examples, an FDR method may include injecting a voltage into the line and monitoring the resulting current. For example, a broadband pulse may be injected. A homogeneous infinitely broadband spectrum in the frequency domain may be injected, which has a waveform a delta function pulse in time:

[0074] Since this pulse has an infinite bandwidth, the pulse may be subjected to a bandpass filter to fit into the available bandwidth. For example, a Fourier domain function may be multiplied with a window function W(co)'.where C. C. represents the complex conjugate. The resulting voltage pulse may then have the shape of the Fourier transform of the window function, modulated around the centerfrequency m0.

[0075] It may be advantageous to select a window function which has a low level of sidelobes, since each sidelobe may look like an additional reflection. For example, for a “boxcar” window, W7(m) = 1 for —Am / 2 < co < Am / 2 and 0 elsewhere, the Fourier transform has the shape of a sine function, whose highest sidelobes are just 13 dB below the main lobe. In contrast, a Hamming window, W (co) = 0.54-0.46 • cossidelobes which are down by 40dB, at the price of a somewhat wider main lobe.

[0076] Once the voltage pulse is transmitted, the current may be monitored. If the measurement is performed in the frequency domain, the measurement consists of applying a constant amplitude alternating voltage to the line, and measuring the resulting frequencydependent current 1(a)). Then, in order to recover the time-dependent shape, the result may be weighed with the appropriate voltage w eight W(OJ) and perform the integration:

[0077] In some examples, the integral of Equation (13) may be replaced by a Discrete Fourier Transform (DFT).

[0078] In some examples, an FDR method may include the following steps: (1) perform a set of narrowband measurements where one injects an alternating voltage and measures the resulting current (or injects an alternating current and measures the resulting voltage); (2) calculate the resulting admittance from the recorded currents measurements; (3) perform a (possibly weighted) inverse DFT on the resulting currents (it may be advantageous in this step to first remove the mean current, as this represents the characteristic admittance of the cable and is not of interest in the detection of faults); and (4) identify peaks in the resulting time-domain current. Each peak may represent a reflection from at least one impedance discontinuity, with the time signifying the two-way delay of the reflection.

[0079] In some examples, there may not usually be a one-to-one correspondence between time-domain peaks and impedance discontinuities such as faults. For example, each discontinuity may give rise to multiple reflections going back and forth along the cable until such reflections die down, e.g., even for a single cable with a single fault, since the point of measurement may also constitute an impedance discontinuity. In more complexcases there may be multiple reflection points, with the signal bouncing off between them giving rise to a multitude of reflections.

[0080] The complexity of multiple reflections may be mitigated, e.g., if a marker that selectively modifies the impedance at a location of the line based on the occurrence of a condition, e.g., a fault, the modified impedance resulting in a relatively strong reflection that may occur at a known location along the powerline. In accordance with the techniques and systems disclosed herein, methods and systems for monitoring a powerline using reflectometry sensors and markers. In some examples, the systems and techniques include a sensor, e.g., reflectometry sensor 516 and / or reflectometry sensor 616, such as at a node (e.g., nodes 222, node 522, and / or node 622) and a marker positioned along the powerline, such as illustrated and described in FIGS. 6-13, may be used.

[0081] FIG, 6 is a schematic diagram of example implementations, or deployments, of a reflectometry sensor 616 and marker 702 on an electrical power network or grid 700. In the example shown, electrical power network 700 includes node 622a including reflectometry sensor 616 and coupled to power cable 100 at electrical equipment 504a at a first location A, and a node 622b including a marker 702a and / or 702b and coupled to power cable 100 at electrical equipment 504b at a second location B. Additionally or alternatively, electrical power network 700 may include splice 704 including marker 702c at a third location C, Additionally or alternatively, electrical power network 700 may include marker 702d at a fourth location D. Additionally or alternatively, node 622b include reflectometry sensor 616.

[0082] In the example shown, electrical equipment 504a and 504b may be substantially the same as electrical equipment 504 described above, and nodes 622a and 622b may be substantially the same as nodes 222 and / or 522 described above, except for tire differences described herein. Reflectometry sensor 616 may be configured to inject a reflectometry signal through cable 100 and acquire reflectometry data through electrical cable 100, e.g., reflectometry data including reflectometry signal responses and / or reflections.Reflectometry sensor 616 may be substantially similar to reflectometry sensor 616, except that reflectometry sensor 618 may couple to electrical cable 100 via an inductive coupling. Reflectometry sensors 616 and 618 are examples of reflectometry' sensors that may couple to cable 100 inductively, capacitively, via direct electrical connection, or via any suitable coupling.

[0083] Node 622b may be at a termination of cable 100 at location B. Marker 702a may be positioned on or adjacent to cable 100 at location B. In the example shown, marker 702a is electrically coupled to ground connection 542. For example, marker 702a may include an impedance modifier that is positioned on, circumferentially around, or adjacent to ground connection 542 and is magnetically coupled, capacitively coupled, inductively coupled, or directly (e.g., conductively) coupled via a direct electrical connection to ground connection 542. The impedance modifier of marker 702a may be configured to change the impedance of cable 100 at location B, e.g., by at least one of magnetically coupling, capacitively coupling, inductively coupling, conductively coupling, galvanically coupling, or any suitable coupling to the electrical cable at the location such that the reflectometry signal is observable by reflectometry sensor 616. For example, the impedance modifier of marker 702a may be configured to couple capacitively or inductively, e.g., through electrical and / or magnetic fields. In some examples, marker 702a may be used to identify location B and / or an electrical distance from reflectometry sensor 616 (e.g., location A) to location B. In some examples, rather than coupling to ground connection 542, the impedance modifier of marker 702a may be coupled (magnetically, capacitively, inductively, conductively, or the like) to a conductor of cable 100 at location B, e.g., similar to marker 702d described below. In some examples, the impedance modifier of marker 702a may be coupled (magnetically, capacitively, inductively, conductively, or the like) about the entire cable 100 at location B, e.g., coupling to any or all of a conductor, a cable shield, a conductor screen, a semicon, or any suitable conductive layer of cable 100.

[0084] Marker 702b may be positioned on or adjacent to cable 100 at location B. Marker 702b may be substantially similar to marker 702a, only positioned at the termination (e.g., node 622b) past the point where the cable shield of cable 100 exits the termination and extends to the equipment ground, e.g., ground connection 542. In some examples, the impedance modifier of marker 702b may be coupled (magnetically, capacitively, inductively, conductively, or the like) to the conductor of cable 100 at any suitable cable accessory (e.g., of which node 622b is one example).

[0085] Marker 702c may be positioned on, adjacent to, within, or around splice 704 at location C. Marker 702c may be substantially similar to marker 702a, only positioned on, adjacent to, or around a cable shield, splice shield, cable conductor, splice conductor orelectrode of splice 704. In some examples, marker 702c may be positioned circumferentially around splice 704, e.g., such that the impedance modifier of marker 702c is coupled (magnetically, capacitively, inductively, conductively, or the like) to a component of, or the entirety of, splice 704. For example, marker 702c may be applied over splice 704 without opening the jacket of splice 704.

[0086] Marker 702d may be positioned on, adjacent to, or around cable 100 at location D.Marker 702d may be substantially similar to marker 702c, only positioned on, adjacent to, or around a cable shield, cable conductor, conductor screen, semicon, or any suitable conductive layer, or the entirety of, cable 100. In some examples, marker 702d may be positioned circumferentially around cable 100, e.g., such that the impedance modifier of marker 702c is coupled (magnetically, capacitively, inductively, conductively, or the like) to a component of, or the entirety of, splice 704. For example, marker 702c may be applied over splice 704 without opening the jacket of splice 704.

[0087] Markers 702a-702d (collectively, “markers 702”) may include an impedance modifier comprising a manually applied modifier, e.g., physically positioned on, around, or adjacent to cable 100 or an accessory connected to cable 100, a modifier with a bypass resistance variation, an IIFCT, an IIFCT with a termination resistance variation, or any suitable component configured to modify, or change, an impedance of cable 100 at a particular location along cable 100, In some examples, the impedance modifier of markers 702 may comprise ferrite, or a ferrite bead.

[0088] For example, FIG. 7 is a schematic diagram of an example implementation, or deployment, of a reflectometry sensor 616 and marker 802 including a impedance modifier 804 and a switch 806 on an electrical power network or grid 800. In the example shown, electrical power network 800 and marker 802 maybe substantially similar to electrical power network 700 and marker 802a of FIG. 6 except for the differences described herein. In some examples, impedance modifier 804 may comprise a ferrite bead. Impedance modifier 804 may be positioned on, in contact with, substantially near and / or adjacent to, or circumferentially around, cable 100, shield 104, central conductor 112, and / or ground connection 542.

[0089] In some examples, marker 802 includes just impedance modifier 804. Marker 802 may be manually positioned at location A and / or removed, such as by an operator positioning impedance modifier 804 circumferentially around ground connection 542and / or removing impedance modifier 804 from ground connection 542. Impedance modifier 804 may be any type of magnetic bead and / or magnetic material configured to modify the impedance of cable 100 when positioned on, adjacent to, or around cable 100, or a component of cable 100 or connected or coupled to cable 100 (e.g., ground connection 542), or an accessory' connected or coupled to cable 100 (e.g., node 622b, splice 704).

[0090] Impedance modifier 804 may be configured to cause the reflectometry signal response comprising a reflection signal indicative of a change of at least one of an impedance or a capacitance at the location of marker 802, e.g., the location of impedance modifier 804. For example, impedance modifier 804 may be configured to cause the reflectometry signal response by causing an impedance and / or capacitance change of cable 100 at the location. In some examples, impedance modifier 804 may be configured to change the impedance of cable 100 at the location of marker 802 along cable 100 by magnetically coupling to cable 100, a central conductor 112 of cable 100, a shield 104 of cable 100, and / or a ground connection 542 of a node, e.g., node 622b or a ground connection of cable 100. In some examples, impedance modifier 804 may be configured to couple to electrical cable 100 in parallel, e.g., electrically in parallel with the impedance of cable 100.

[0091] In some examples, impedance modifier 804 may be configured to cause the reflectometry signal response for relatively high frequencies, e.g., greater than or equal to about 1 kilohertz (kHz), and to not cause a reflectometry signal response for relatively low frequencies, e.g., less than about 1 kHz. In some examples, the reflectometry signal may comprise an FDR signal or a TDR signal, the reflectometry data may comprise FDR data or TDR data, and impedance modifier 804 may be configured to cause an FDR signal response or a TDR signal response, e.g., the reflectometry signal response caused by impedance modifier 804 may comprise an FDR signal response or a TDR signal response.

[0092] Ferrite bead 804 may be configured to cause a reflectometry signal response at a location along cable 100 where marker 802 is positioned, e.g., at location B in the example shown. For example, ferrite bead 804 may be configured to interfere with the propagation of the reflectometry signal injected through cable 100 by reflectometry sensor 616 and cause a reflection originating from the location, e.g., location B. The reflection may be acquired by reflectometry sensor 616, e.g., as reflectometry data. In some examples, ifreflectometry data acquired by reflectometry sensor 616 before and after ferrite bead 804 is positioned on, around, or adjacent to cable 100 (or before and after bypassing ferrite bead 804 positioned on, around, or adjacent to cable 100) and compared, the location (location B) may be indicated in a plot of impedance as a function of distance from reflectometry sensor 616. In some examples, if the distance from reflectometry sensor 616 and location B is known, the acquired reflectometry data including a reflectometry signal response from marker 802 may be indicative of a velocity of propagation (e.g., of a reflectometry signal) along cable 100 between locations A and B. Alternatively, if the velocity of propagation (e.g., of a reflectometry signal) along cable 100 between locations A and B is known, the acquired reflectometry data including a reflectometry signal response from marker 802 may be indicative of a distance along cable 100 between locations A and B.

[0093] In some examples, marker 802 includes switch 806. Switch 806 may be configured to selectively bypass impedance modifier 804. For example, impedance modifier may be manually and / or remotely “positioned” or “removed” by manually or remotely closing or opening switch 806, respecti vely. Switch 806 may be an on-off switch configured to be operated manually, e.g., locally by an operator, or may be automatically operated by local electronics, or configured to be remotely operated by remotely controlling (by an operator, remote electronics, or a computing device) switch 806 or local electronics to control switch 806, or switch 806 may be a timed switch configured to open and close based on a timing. In some examples, switch 806 may be an electrical switch, a relay, a solid state switch, a transistor such as a metal-on-silicon field effect transistor (MOSFET), a magnetic switch, a mechanical switch, or any switch suitable to vary a resistance along an electrical path between, and including, open and short.

[0094] When switch 806 is closed (e.g., shorted, a low resistance path, marker 802 is “off’), a reflectometry signal may bypass impedance modifier 804 and impedance modifier 804 may not cause a reflectometry signal response at location B. When switch 806 is open (e.g., a high resistance path, marker 802 is “on”), reflectometry signal may not bypass impedance modifier 804 and impedance modifier 804 may cause a reflectometry signal response at location B.

[0095] In some examples, switch 806 may be a resistance modifier configured to have a variable resistance, e.g., between short and open. Impedance modifier 804 may then causea variable reflectometry signal response at location B, e.g., having a variable response strength or amplitude. In some examples, switch 806 may be configured to have a timed sequence of continuous resistance variation (for which impedance modifier 804 correspondingly causes the timed sequence of continuous reflectometry signal response variation) or discontinuous (e.g., open-close) resistance variation. In some examples, switch 806 may be a powered switch configured to receive electrical power through a local direct power source such as the mains or a battery, or switch 806 may be configured to harvest power, e.g., from cable 100.

[0096] In some examples, switch 806 may comprise an HFCT termination and impedance modifier 804 may be a shield coupled impedance modifier such as an HFCT. For example, an HFCT as impedance modifier 804 may include a ferrite material and a plurality of windings connected to HFCT termination by a coaxial cable, and variation of the resistance or impedance at the coaxial connection by the HFCT termination (e.g., including and between short and open and functioning as switch 806) may cause the HFCT (e.g., impedance modifier 804) to cause a correspondingly variable reflectometry signal response,

[0097] In some examples, marker 802 may be a condition monitor, or configured to operate as a condition monitor. For example, marker 802 and / or impedance modifier 804 of marker 802 may be configured to selectively cause a reflectometry signal response at location B based on a condition of cable 100 and / or an accessory connected to cable 100. Marker 802 may be configured to selectively cause a reflectometry signal response at location B based on the presence or absence of the condition, or to selectively cause a varying reflectometry signal response based on an amount, amplitude, value, or the like, of the condition. For example, the condition may be a temperature, a humidity, a water ingress, a water submersion, a defect, or the like.

[0098] In some examples, marker 802 may monitor may be configured to monitor a condition via switch 806. For example, switch 806 may be a condition monitor configured to selectively bypass impedance modifier 804 by being configured to vary a resistance, e.g., between and including open and short, of an electrical path configured bypass impedance monitor 804 based on the presence, absence, or amount of the condition. The varying resistance of the bypass path to impedance modifier 804, via a conditiondependent switch 806, may cause a corresponding variation in the reflectometry signalresponse caused by impedance monitor 804, In some examples, switch 806 may comprise a bi-metallic strip, a thermistor, or any suitable condition-dependent switch. For example, switch 806 as a bi-metallic strip may be configured to close (or open) based on a temperature of the bi-metallic strip being less than or equal to a threshold temperature. The bi-metallic strip may be positioned on or adjacent to cable 100, an accessory of cable 100, or a component or material connected to cable 100 to function as a temperature sensor of cable 100, the accessory, or the component or material.

[0099] FIGS. 8-11 are schematic cross-sectional diagrams of a splice illustrating example arrangemen ts of one or more markers. FIG. 8 is a schematic cross-sectional diagram of a splice 900 illustrating an example arrangement of a marker 802. in the example shown, splice 900 includes splice jacket 902, shield connector 904, splice connector 912, splice insulator 906, and splice electrodes 922a and 922b, Splice 900 may be configured to electrically connect a discontinuous portion of cable 100. Splice 900 may be an example of splice 704 of FIG. 6.

[0100] Splice connector 912 and splice electrodes 922 may be configured to electrically connect conductive core 112 of cable 100, and shield connector 904 may be configured to electrically connect shield 104 of cable 100. Marker 802 may be positioned at splice 900, e.g., within splice jacket 902. In the example shown, impedance modifier 804 is positioned circumferentially around shield 104 of cable 100 within splice 900, and switch 806 is also within splice jacket 904. Marker 802 may be configured to monitor a condition of cable 100 at the location of splice 900 and / or to monitor a condition of splice 900. For example, switch 806 may be configured to selectively bypass impedance modifier 804 based on a condition of splice 900 and / or cable 100 at splice 900, e.g., a temperature, a humidity, a water ingress and / or water submersion or any suitable condition. In the example shown, impedance modifier is configured to magnetically couple to cable 100 at the location of splice 900, e.g., to magnetically couple to shield 104, so as to cause a reflectometry signal response, when not bypassed, at the location of splice 900.

[0101] FIG. 9 is a schematic cross-sectional diagram of a splice 1000 illustrating an example arrangement of a plurality of markers 802, e.g., marker 802a and marker 802b. Splice 1000 may be substantially similar to splice 900 described above except for the differences described herein. In the example shown, splice 1000 includes splice jacket 902, shield connector 904, splice connector 912, splice insulator 906, and splice electrodes922a and 922b. Splice 1000 may be configured to electrically connect a discontinuous portion of cable 100. Splice 1000 may be an example of splice 704 of FIG. 6. Splice 1000 may be configured to monitor multiple conditions of the same or different types.

[0102] Markers 802a and 802b (collectively, “markers 802”) may be positioned at splice 1000, e.g., within splice jacket 902. In the example shown, impedance modifiers 804a and 804b are positioned circumferentially around shield 104 of cable 100 within splice 1000, and switches 806a and 806b is also within splice jacket 904. Marker 802a and 802b maybe configured to monitor a plurality of conditions of the same or different ty pe of cable 100 at the location of splice 1000, and / or to monitor a plurality' of conditions of the same or different type of splice 1000.

[0103] For example, switch 806a may be configured to selectively bypass (or selectively not bypass) impedance modifier 804a based on a first condition of splice 1000 and / or cable 100 at splice 1000, and switch 806b may be configured to selectively bypass (or selectively not bypass) impedance modifier 804b based on a second condition of splice 1000 and / or cable 100 at splice 1000, e.g., at substantially the same location. For example, the first and second conditions may be local conditions of splice 1000 and / or cable 100. Tire first condition may be a first temperature, and switch 806a may be configured to selectively bypass (or selectively not bypass) impedance modifier 804a based on the temperature of splice 1000 and / or cable 100 being greater than or equal to (or less than or equal to) the first temperature. Tire second condition may be a second temperature different from the first temperature, and switch 806b may be configured to selectively bypass (or selectively not bypass) impedance modifier 804b based on the temperature of splice 1000 and / or cable 100 being greater than or equal to (or less than or equal to) the second temperature.

[0104] In some examples, switch 806a may comprise a resistance modifier configured to change resistance based on the first local condition, e.g., the first temperature, and switch 806b may comprise a resistance modifier configured to change resistance based on the second local condition, e.g., the second temperature. Impedance modifier 804a may be configured to cause a first impedance change (which may be continuously variable) and a corresponding first reflectometry signal response of a first amount (e.g., reflection magnitude and / or strength) based on the resistance of switch 806a, and impedance modifier 804b may be configured to cause a second impedance change (which may becontinuously variable) and a corresponding second reflectometry signal response of a second amount (e.g., reflection magnitude and / or strength) based on the resistance of switch 806b. The first and second reflectometry signal responses may be indicative of the first and second impedance changes, respectively. The first and second impedance changes may be additive, and the first and second reflectometry signal responses may be additive, and reflectometry sensor 616 may be configured to acquire reflectometry data including indicative of one or both of the first and second reflectometry signal responses. Processing circuitry (e.g., of reflectometry sensor 616, central system 220, or of a computing device) may be configured to determine the first and second conditions based on the reflectometry data including both the first and second reflectometry signal responses.

[0105] For example, the processing circuitry’ may be configured to determine whether the temperature of splice 1000 and / or cable 100 is less than a first threshold temperature (e.g., the first condition), greater than or equal to the first threshold temperature but less than a second threshold temperature (e.g., the second condition), or greater than the second threshold temperature, based on the reflectometry data including the first and second reflectometry signal responses. In some examples, the first condition may be of a first type, e.g., a temperature, and the second condition may be of a second type, e.g., a humidity’. Switches 806a and 806b may be configured to selectively bypass impedance modifiers 804a and 804b, respectively, by a variable amount via a variable resistance based on conditions of the same or different types, e.g., such that the first and second reflectometry signal responses are indicative of a continuous value of the first and second conditions, respectively.

[0106] FIG. 10 is a schematic cross-sectional diagram of a splice 1100 illustrating another example arrangement of a marker 1102 including a plurality of switches 806, e.g., switches 806a and 806b. Splice 1100 may be substantially similar to splices 900 and 1000 described above except for the differences described herein. In the example shown, splice 1100 includes splice jacket 902, shield connector 904, splice connector 912, splice insulator 906, and splice electrodes 922a and 922b. Splice 1100 may be configured to electrically connect a discontinuous portion of cable 100. Splice 1100 may be an example of splice 704 of FIG. 6. Splice 1100 may be configured to monitor multiple conditions of the same or different types.

[0107] Markers 1102 may be positioned at splice 1000, e.g., within splice jacket 902. In the example shown, impedance modifier 804 is positioned circumferentially around shield 104 of cable 100 within splice 1100, and switches 806a and 806b is also within splice jacket 904. Marker 1102 may be configured to monitor a plurality of conditions of the same or different type of cable 100 at the location of splice 1000, and / or to monitor a plurality' of conditions of the same or different type of splice 1000.

[0108] For example, switch 806a may be configured to selectively bypass impedance (or selectively not bypass) modifier 804 based on a first condition of splice 1100 and / or cable 100 at splice 1100, and switch 806b may be configured to selectively bypass (or selectively not bypass) the same impedance modifier 804 based on a second condition of splice 1100 and / or cable 100 at splice 1100, e.g., at substantially the same location. For example, the first and second conditions may be local conditions of splice 1100 and / or cable 100. Switch 806a comprise a first resistance modifier configured to change resistance based on the first local condition, thereby selectively bypassing impedance modifier 804 (e.g., by a continuously variable amount) to cause impedance modifier to selectively' cause an impedance change and corresponding reflectometry signal response (e.g., by a continuously variable amount) based on the first condition. Switch 806b comprise a second resistance modifier configured to change resistance based on the second local condition, thereby selectively bypassing the same impedance modifier 804 (e.g., by a continuously variable amount) to cause impedance modifier to selectively cause an impedance change and corresponding reflectometry' signal response (e.g., by a continuously variable amount) based on the second condition. In some examples, the first and second conditions may be different values of the same type of condition, or different types of conditions, e.g., different temperature values of a temperature, or a temperature and a humidity or water ingress.

[0109] In some examples, switches 806a and 806b may be configured to selectively bypass (or selectively not bypass) impedance modifier 804 based on conditions at different locations, e.g., as illustrated in FIG. 11. FIG. 11 is a schematic cross-sectional diagram of a splice 1200 illustrating another example arrangement of a marker 1202 including a plurality' of switches 806, e.g., switches 806a and 806b. Splice 1200 may' be substantially similar to splice 1100 and marker 1202 may be substan tially similar to marker 1102 described above except for the differences described herein. In the example shown, splice1200 includes splice jacket 902, shield connector 904, splice connector 912, splice insulator 906, and splice electrodes 922a and 922b. Splice 1200 may be configured to electrically connect a discontinuous portion of cable 100. Splice 1200 may be an example of splice 704 of FIG. 6. Splice 1200 may be configured to monitor multiple conditions of the same or different types at a plurality of locations.

[0110] In the example shown, impedance modifier 804 of marker 1202 is positioned circumferentially around shield 104 of cable 100 within splice 1100, and switch 806a is also within splice jacket 904. Switch 806b, however, is positioned on or adjacent to cable 100 at a second location some distance from the first location of switch 806a. Marker 1202 may be configured to monitor a plurality of conditions of the same or different type at a plurality of locations, e.g., locations of cable 100, splice 1200, at the location of splice 1200, and / or to monitor a plurality of conditions of the same or different type of splice 1200.

[0111] In some examples, marker 1202 may be configured to indicate temperature differences between splice 1200 and cable 100. For example, switches 806a and 806b may be connected in parallel. At a temperature range where the splice switch 806a activates and the cable switch 806b does not, impedance modifier 804 is not bypassed. In some examples, thermal runaway of splice 1200 may be indicated by a temperature differential between splice 1200 and cable 100 that increases overtime, and marker 1202 may be configured to be indicative of a severity of the splice thermal runaway.

[0112] FIG. 12 is a schematic cross-sectional diagram of a splice 1300 illustrating another example arrangement of a marker 1352 including an impedance modifier 1354 and a switch 1356, In the example shown, splice 1300 includes splice jacket 1302, shield connector 1304, splice connector 1312, splice insulator 1306, splice electrodes 1322a and 1322b, and splice semicon 1310 (e.g., splice semiconductor shield) connected to cable semicon 111. Splice 1300 may be configured to electrically connect a discontinuous portion of cable 100. Splice 1300 may be an example of splice 704 of FIG. 6.

[0113] Splice connector 1312 and splice electrodes 1322 may be configured to electrically connect conductive core 112 of cable 100, and shield connector 1304 may be configured to electrically connect shield 104 of cable 100. Marker 1352 may be positioned at splice 1300, e.g., within splice jacket 1302.

[0114] In the example shown, impedance modifier 1354 comprises a dielectric material1355 positioned between splice semicon 1310 and shield connector 1304 (e.g., a splice sock shield in the example shown) and configured to electrically separate splice semicon 1310 and shield connector 1304. The splice semicon 1310 and shield connectors 1304, normally not electrically separated, form a capacitor (or increase a capacitance of splice 1300) when electrically separated. Impedance modifier 1354 may be configured to modify impedance at splice 1300 by changing (e.g., increasing) a capacitance at splice 1300, thereby causing a reflectometry signal reflection, e.g., a reflectometry signal response, at splice 1300. For example, impedance modifier 1354 may comprise a capacitor positioned to be in series with a capacitance of cable 100 (and / or splice 1300) at splice 1300, e.g., impedance modifier 1354 may be configured to change the impedance at the location (e.g., splice 1300) by capacitively coupling to cable 100 at splice 1300.Switch 1356 may be electrically connected between splice semicon 1310 and shield connector 1304 to selectively bypass impedance modifier 1354. Switch 1356 may be a resistance modifier and / or an open-short switch, e.g., substantially similar to switch 806 described above.

[0115] FIG. 13 is a schematic cross-sectional diagram of a splice 1400 illustrating another example arrangement of a marker 1452 including an impedance modifier 1454 and switch 1356. Splice 1400 may be substantially similar to splice 1300 except for the differences described herein, For example, splice 1400 may be similar to splice 1300 except that splice 1400 includes splice conductor 1411 comprising a conductive material (e.g., a high conductive material such as a metal) distributed over the low'er conductivity splice surface material and / or over the splice semicon 1310. In the example shown, splice conductor 1411 comprises a spiral wrap. In other examples, splice conductor 1411 may comprise a mesh or continuous coating. Splice 1400 may be configured to electrically connect a discontinuous portion of cable 100. Splice 1300 may be an example of splice 704 of FIG.6.

[0116] FIG. 14 is a conceptual block diagram of another example electrical power network 1500 including a reflectometry sensor 616 and marker 802 and including a plurality of branched segments 1502-1514 of the electrical power network 1500. FIG. 14 also illustrates a plot of a reflectometry' signal as a function of location along the plurality of branches 1502-1514 of the electrical power network 1500, e.g., illustrating reflectometry signal responses 1530-1544 from entities (e.g., components, splices,junctions, terminations, and impedance modifier 802) indicative of the location and impedance change (e.g., relative to the impedance of cable of electrical power network 1500) of the respective entities.

[0117] In the example shown, electrical power network 1500 includes junction bars 1520a, 1520b, and 1520c. Junction bars 1520a-1520c may be switches. Junction bar 1520a may be a junction between branches 1502-1506, junction bar 1520b may be a junction between branches 1506, 1512, and 1514, and junction bar 1520c may be a junction between branches 1502, 1508, and 1510. Reflectometry sensor 616 may be connected to electrical power network 1500 at junction bar 1520a, and marker 802 may be positioned at junction bar 1520b. Generally, marker 802 may be positioned on, adjacent to, or around a power cable of electrical power network 1500 anywhere along electrical power network 1500,

[0118] Reflectometry responses 1530-1544 may occur at any location having an impedance change, e.g., junction bars 1520a- 1520c, terminations 1522a-1522e, and marker 802 in the example shown. The reflectometry signal response 1532 at junction bar 1520b may include reflectometry’ signal responses due to both junction bar 1520b and marker 802.

[0119] Marker 802 may be configured to cause reflectometry signal response 1532, or change reflectometry’ signal response 1532, by causing an impedance change (or modifying an impedance change) at its location, e.g., at junction bar 1520b. The impedance change caused by marker 802 may affect the reflectometry signal upstream (relative to marker 802 from reflectometry sensor 616) from marker 802 and / or downstream from marker 802, For example, marker 802 may be configured to cause (or change) a first reflectometry signal response 1532 at a first location, e.g., junction bar 1520a and to change a second reflectometry' signal response at a second location, e.g., reflectometry signal responses 1538 and 1544 at terminations 1522d and 1522e, respectively. For example, marker 802 may cause, or increase, reflectometry signal response 1532 (e.g., 1532 increases in amplitude / magnitude) by increasing the impedance at junction bar 1520b, which then causes a decrease in downstream impedance changes at terminations 1522d and 1522e and corresponding decreases in reflectometry signal responses 1538 and 1544. In some examples, marker 802 may cause, or increase, reflectometry signal response 1532 (e.g., 1532 increases in amplitude / magnitude) byincreasing the impedance at junction bar 1520b, which then causes an increase in upstream (relative to marker 802 from impedance sensor 616) impedance changes at junction bar 1520c and terminations 1522a-1522c and corresponding increases in reflectometry signal responses 1534, 1536, 1540, and 1542. In some examples, marker 802 may not cause, or decrease, reflectometry signal response 1532 (e.g., 1532 decreases in amplitude / magnitude) by decreasing the impedance at junction bar 1520b (e.g., turning marker 802 “off” by closing switch 806 to selectively bypass impedance modifier 804 of marker 802, causing a decrease in impedance change relative to marker 802 being “on”), which then causes a corresponding increase in downstream impedance changes and reflectometry signal responses and decrease in upstream impedance changes and reflectometry signal responses.

[0120] FIG. 15 is a flowchart illustrating example techniques for monitoring an electrical powerline and / or electric power network, in accordance with this disclosure. FIG. 15 is described with respect to cable 100 of FIGS. 1-2, electrical power network 200, nodes 222, and central computing system 220 of FIG. 3, monitoring node 622, reflectometry sensor 616, and markers 802, 1302, and 1402 of FIGS, 5-14. However, other devices may be used to perform techniques of FIG. 15.

[0121] Reflectometry sensor 616 may inject a reflectometry signal onto cable 100 of an electrical powerline (1602). In some examples, the reflectometry’ signal may be an FDR signal or a TDR signal.

[0122] A condition may cause switch 806 or 1356 of markers 802, 1352, or 1452 positioned on, around, or adjacent to cable 100 at a location along cable 100 to selectively bypass impedance modifier 804, 1354, or 1454 (1604). For example, the condition may be a temperature, a humidity, a water ingress or submersion, a defect, or the like.Selectively bypassing impedance modifier 804, 1354, or 1454 may selectively cause a change to the reflectometry signal response at the location, e.g., bypassing the impedance modifier may cause an absence of a reflectometry signal response at the marker location by removing a reflection by the impedance modifier from the reflectometry signal.Alternatively or additionally, markers 802, 1352, or 1452 may be configured to work in the opposite manner. For example, a condition may cause switch 806 or 1356 of markers 802, 1352, or 1452 positioned on, around, or adjacent to cable 100 at a location along cable 100 to selectively not bypass impedance modifier 804, 1354, or 1454 (1604).Selectively not bypassing impedance modifier 804, 1354, or 1454 may selectively cause a reflectometry signal response at tire location,

[0123] Reflectometry sensor 616 may acquire reflectometry data indicative of the reflectometry signal response (or lack thereof) (1606), and processing circuitry of central computing system 220 may determine, based on processing circuitry and based on the reflectometry data, the condition (1608). In some examples, the processing circuitry may determine the location based on the reflectometry data.

[0124] In the present detailed description of the preferred embodiments, reference is made to the accompanying drawings, which illustrate specific embodiments in which the invention may be practiced. The illustrated embodiments are not intended to be exhaustive of all embodiments according to the invention. It is to be understood that other embodiments may be utilized, and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0125] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term "‘about.” Accordingly, unless indicated to the contrary', the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

[0126] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and / or” unless the content clearly dictates otherwise.

[0127] Spatially related terms, including but not limited to, “proximate,” “distal,” “lower,” “upper,” “beneath,” “below,” “above,” and “on top,” if used herein, are utilized for ease of description to describe spatial relationships of an element(s) to another. Such spatially related terms encompass different orientations of the device in use or operation in addition to the particular orientations depicted in the figures and described herein. For example, if an object depicted in the figures is turned over or flipped over, portions previouslydescribed as “below” or “beneath” other elements would then be above or on top of those other elements.

[0128] The techniques of this disclosure may be implemented in a wide variety of computer devices, such as servers, laptop computers, desktop computers, notebook computers, tablet computers, hand-held computers, smart phones, and the like. Any components, modules or units have been described to emphasize functional aspects and do not necessarily require realization by different hardware units. The techniques described herein may also be implemented in hardware, software, firmware, or any combination thereof. Any features described as modules, units or components may be implemented together in an integrated logic device or separately as discrete but interoperable logic devices. In some cases, various features may be implemented as an integrated circuit device, such as an integrated circuit chip or chipset. Additionally, although a number of distinct modules have been described throughout this description, many of which perform unique functions, all the functions of all of the modules may be combined into a single module, or even split into further additional modules. The modules described herein are only exemplary and have been described as such for better ease of understanding,

[0129] If implemented in software, the techniques may be realized at least in part by a computer-readable medium comprising instructions that, when executed in a processor, performs one or more of the methods described above. Tire computer-readable medium may comprise a tangible computer-readable storage medium and may form part of a computer program product, which may include packaging materials. The computer-readable storage medium may comprise random access memory (RAM) such as synchronous dynamic random-access memory (SDRAM), read-only memory (ROM), non-volatile random-access memory (NVRAM), electrically erasable programmable readonly memory (EEPROM), FLASH memory, magnetic or optical data storage media, and the like. The computer-readable storage medium may also comprise a non-volatile storage device, such as a hard-disk, magnetic tape, a compact disk (CD), digital versatile disk (DVD), Blu-ray disk, holographic data storage media, or other non-volatile storage device.

[0130] Hie term “processor,” as used herein may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein, In addition, in some aspects, the functionality described herein may be provided within dedicated software modules or hardware modules configured for performing thetechniques of this disclosure. Even if implemented in software, the techniques may use hardware such as a processor to execute the software, and a memory to store the software. In any such cases, the computers described herein may define a specific machine that is capable of executing the specific functions described herein. Also, the techniques could be fully implemented in one or more circuits or logic elements, which could also be considered a processor.

[0131] In one or more examples, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over, as one or more instructions or code, a computer-readable medium and executed by a hardware -based processing unit.Computer-readable media may include computer-readable storage media, which corresponds to a tangible medium such as data storage media, or communication media including any medium that facilitates transfer of a computer program from one place to another, e.g., according to a communication protocol. In this manner, computer-readable media generally may correspond to (1) tangible computer-readable storage media, which is non-transitory or (2) a communication medium such as a signal or carrier wave. Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and / or data structures for implementation of the techniques described in this disclosure. A computer program product may include a computer-readable medium.

[0132] By way of example, and not limitation, such computer-readable storage media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. It should be understood, however, that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transient media, but are insteaddirected to non-transient, tangible storage media. Disk and disc, as used, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0133] Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor”, as used may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described. In addition, in some aspects, the functionality described may be provided within dedicated hardware and / or software modules. Also, the techniques could be fully implemented in one or more circuits or logic elements.

[0134] The techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC) or a set of ICs (e.g., a chip set). Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, various units may be combined in a hardware unit or provided by a collection of interoperative hardware units, including one or more processors as described above, in conjunction with suitable software and / or firmware.

[0135] It is to be recognized that depending on the example, certain acts or events of any of the methods described herein can be performed in a different sequence, may be added, merged, or left out altogether (e.g., not all described acts or events are necessary for the practice of the method). Moreover, in certain examples, acts or events may be performed concurrently, e.g., through multi-threaded processing, interrupt processing, or multiple processors, rather than sequentially.

[0136] In some examples, a computer-readable storage medium includes a non-transitory medium. Hie tern “non-transitory” indicates, in some examples, that the storage medium is not embodied in a carrier wave or a propagated signal. In certain examples, a non-transitory storage medium stores data that can, over time, change (e.g., in RAM or cache).

[0137] The following numbered clauses demonstrate various aspects of this disclosure:

[0138] Clause 1: A system configured to monitor an electric powerline, the system including: a sensor configured to acquire a reflectometry data through the electrical cable; an impedance modifier positioned on or adjacent to the electrical cable at a location along the electrical cable, the impedance modifier configured to cause a reflectometry signal response at the location; and a switch configured to selectively bypass the impedance modifier.

[0139] Clause 2: The system of clause 1, wherein the reflectometry signal response includes a reflection signal indicative of a change of at least one of an impedance or a capacitance at the location.

[0140] Clause 3: The system of clause 2, wherein the impedance modifier is configured to cause the reflectometry signal response for relatively high frequencies and to not cause the reflectometry signal response for relatively low frequencies.

[0141] Clause 4: The system of clause 3, wherein the relatively high frequencies correspond to frequencies greater than or equal to 1 kilohertz (kHz), wherein the relatively low frequencies correspond to frequencies less than 1 kHz, wherein tire reflectometry data includes at least one of a frequency domain reflectometry (FDR) data or a time domain reflectometry (TDR) data, and wherein the reflectometry signal response includes at least one of an FDR signal response or a TDR signal response.

[0142] Clause 5: The system of any one of clauses 1-4, wherein the impedance modifier is configured to change the impedance at the location by at least one of magnetically coupling or capacitively coupling to the electrical cable at the location.

[0143] Clause 6: The system of any one of clauses 1-5, wherein the reflectometry signal response is a first reflectometry signal response, wherein the location is a first location, wherein the impedance modifier is configured to change a second reflectometry signal response at a second location along the electrical cable.

[0144] Clause 7: The system of clause 6, wherein the second location is along a branch of the electrical cable downstream from the first location relative to the sensor.

[0145] Clause 8: The system of any one of clauses 1-7, wherein the impedance modifier includes at least one of a ferrite bead or a high frequency current transformer.

[0146] Clause 9: The system of any one of clauses 1-8, wherein the impedance modifier is coupled in parallel to at least one of the electrical cable, a ground connection of the31electrical cable, a shield of the electrical cable, or a shield connection of the electrical cable.

[0147] Clause 10: The system of any one of clauses 1-9, wherein the impedance modifier is positioned in contact with or substantially near to the electrical cable.

[0148] Clause 11: The system of any one of clauses 1-10, wherein the impedance modifier is configured to magnetically couple to at least one of a ground connection of the electrical cable or a conductor of the electrical cable.

[0149] Clause 12: The system of any one of clauses 1-11, wherein the impedance modifier is positioned circumferentially around a ground connection of the electrical cable.

[0150] Clause 13: The system of any one of clauses 1-12, wherein the impedance modifier is positioned circumferentially around a conductor of the electrical cable.

[0151] Clause 14: The system of any one of clauses 1-13, wherein the location is at a node operatively coupled to the electrical cable.

[0152] Clause 15: The system of any one of clauses 1-14, wherein the location is at a splice operatively coupled to the electrical cable.

[0153] Clause 16: The system of any one of clauses 1-15, wherein the switch includes a manually controlled switch.

[0154] Clause 17: The system of any one of clauses 1-16, wherein the switch includes at least one of an automatically controlled switch, a timed switch, or a remotely control led switch.

[0155] Clause 18: The system of any one of clauses 1-17, wherein the switch includes an open / close switch or a resistance modifier.

[0156] Clause 19: The system of any one of clauses 1-18, wherein the switch includes a resistance modifier configured to change resistance based on a local condition.

[0157] Clause 20: The system of clause 19, wherein the local condition includes at least one of a temperature, a humidity, or a water submersion.

[0158] Clause 21: The system of any of clauses 19 and 20 or any of clauses 19 and 20, wherein the resistance modifier includes at least one of a bi-metallic strip or a thermistor.

[0159] Clause 22: The system of any one of clauses 19-21, wherein the resistance modifier is configured to change the resistance by changing from at least one of short to open or open to short.

[0160] Clause 23: The system of any one of clauses 1-22, wherein the impedance modifier is a first impedance modifier, wherein the reflectometry signal response is a first reflectometry signal response, wherein the switch is a first switch including a first resistance modifier configured to change resistance based on a first local condition, the system further including: a second impedance modifier positioned on or adjacent to the electrical cable at the location along tire electrical cable, the second impedance modifier configured to cause a second reflectometry signal response at the location; and a second switch configured to bypass the second impedance modifier, the second switch including a resistance modifier configured to change resistance based on a second local condition.

[0161] Clause 24: The system of clause 23, wherein the first reflectometry signal response includes a first reflection signal indicative of a first change of the impedance at the location, wherein the second reflectometry signal response includes a second reflection signal indicative of a second change of the impedance at the location, wherein the first impedance change and the second impedance change are additive, wherein the reflectometry data is indicative of at least one of tire first reflectometry signal response or the second reflectometry signal response,

[0162] Clause 25: The system of any of clauses 23 and 24 or any of clauses 23 and 24, wherein the first local condition includes a first temperature and the second local condition includes a second temperature different from the first temperature,

[0163] Clause 26: The system of any of clauses 23 through 25 or any of clauses 23 through 25, wherein the first local condition includes a temperature and the second local condition includes at least one of a humidity or a water ingress.

[0164] Clause 27: The system of any one of clauses 1-26, wherein the switch is a first switch including a first resistance modifier configured to change resistance based on a first local condition, the system further including: a second switch configured to bypass the impedance modifier, the second switch including a resistance modifier configured to change resistance based on a second local condition.

[0165] Clause 28: The system of clause 27, wherein the first local condition includes a first temperature and the second local condition includes a second temperature different from the first temperature.

[0166] Clause 29: The system of any of clauses 27 and 28, wherein the first local condition includes a temperature and the second local condition includes at least one of a humidity or a water ingress.

[0167] Clause 30: The system of any of clauses 27 through 29, wherein the location is a first location, wherein the first local condition is at the first location, wherein the second local condition is at a second location different from the first location.

[0168] Clause 31: The system of clause 30, wherein the first location is at a splice and the second location is at the electrical cable at a threshold distance from the splice.

[0169] Clause 33: The system of any one of clauses 1-32, wherein the impedance modifier includes a dielectric configured to electrically separate a splice shield of a splice and a splice semicon of the splice, wherein the switch is electrically connected between the splice shield and a conductive material distributed across the splice body and over the splice semi con.

[0170] Clause 34: A marker of an electric powerline including an electrical cable, the marker including: an impedance modifier positioned on or adjacent to the electrical cable at a location along the electrical cable, the impedance modifier configured to cause a reflectometry signal response at the location; and a switch configured to selectively bypass the impedance modifier.

[0171] Clause 35: The marker of clause 34, wherein the FDR signal response includes a reflection signal indicative of a change of at least one of an impedance or a capacitance at the location.

[0172] Clause 36: The marker of clause 35, wherein the impedance modifier is configured to cause the FDR signal response for relatively high frequencies and to not cause the FDR signal response for relatively low frequencies.

[0173] Clause 37: The marker of clause 36, wherein the relatively high frequencies correspond to frequencies greater than or equal to 1 kilohertz (kHz), wherein the relatively low frequencies correspond to frequencies less than 1 kHz, wherein the reflectometry data includes at least one of a frequency domain reflectometry (FDR) data or a time domain reflectometry (TDR) data, and wherein the reflectometry signal response includes at least one of an FDR signal response or a TDR signal response.

[0174] Clause 38: The marker of any one of clauses 34-37, wherein the impedance modifier is configured to change the impedance at the location by at least one of magnetically coupling or capacitively coupling to the electrical cable at the location.

[0175] Clause 39: The marker of any one of clauses 34-38, wherein tire reflectometry signal response is a first reflectometry signal response, wherein the location is a first location, wherein the impedance modifier is configured to change a second reflectometry signal response at a second location along the electrical cable.

[0176] Clause 40: The marker of any one of clauses 34-39, wherein the second location is along a branch of tire electrical cable downstream from the first location relative to the sensor.

[0177] Clause 41: The marker of any one of clauses 34-40, wherein tire impedance modifier includes at least one of a ferrite bead or a high frequency current transformer.

[0178] Clause 42: Tire marker of any one of clauses 34-41, wherein the impedance modifier is coupled in parallel to at least one of the electrical cable, a ground connection of the electrical cable, a shield of the electrical cable, or a shield connection of the electrical cable,

[0179] Clause 43: The marker of any one of clauses 34-42, wherein the impedance modifier is positioned in contact with or substantially near to the electrical cable.

[0180] Clause 44: Tire marker of any one of clauses 34-43, wherein the impedance modifier is configured to magnetically couple to at least one of a ground connection of the electrical cable or a conductor of the electrical cable.

[0181] Clause 45: The marker of any one of clauses 34-44, wherein the impedance modifier is positioned circumferenti ally around a ground connection of the electrical cable.

[0182] Clause 46: The marker of any one of clauses 34-45, wherein the impedance modifier is positioned circumferentially around a conductor of the electrical cable.

[0183] Clause 47: Tire marker of any one of clauses 34-46, wherein the location is at a node operatively coupled to the electrical cable.

[0184] Clause 48: The marker of any one of clauses 34-47, wherein the location is at a splice operatively coupled to the electrical cable.

[0185] Clause 49: The marker of any one of clauses 34-48, wherein the sw itch includes a manually controlled switch.

[0186] Clause 50: The marker of any one of clauses 34-49, wherein the switch includes at least one of an automatically controlled switch, a timed switch, or a remotely controlled switch.

[0187] Clause 1: The marker of any one of clauses 34-50, wherein the switch includes an open / close switch or a resistance modifier.

[0188] Clause 52: Tire marker of any one of clauses 34-51, wherein the switch includes a resistance modifier configured to change resistance based on a local condition.

[0189] Clause 53: The marker of clause 52, wherein the local condition includes at least one of a temperature, a humidity, or a water submersion.

[0190] Clause 54: The marker of clause 52, wherein the resistance modifier includes at least one of a bi-metallic strip or a thermistor.

[0191] Clause 55: Tire marker of any of clauses 52 and 53, wherein the resistance modifier is configured to change the resistance by changing from at least one of short to open or open to short.

[0192] Clause 56: The marker of any one of clauses 34-55, wherein the impedance modifier is a first impedance modifier, wherein the reflectometry signal response is a first reflectometry signal response, wherein the switch is a first switch including a first resistance modifier configured to change resistance based on a first local condition, the system further including: a second impedance modifier positioned on or adjacent to the electrical cable at the location along tire electrical cable, the second impedance modifier configured to cause a second reflectometry signal response at the location; and a second switch configured to bypass the second impedance modifier, the second switch including a resistance modifier configured to change resistance based on a second local condition.

[0193] Clause 57: The marker of clause 56, wherein the first reflectometry' signal response includes a first reflection signal indicative of a first change of the impedance at the location, wherein the second reflectometry signal response includes a second reflection signal indicative of a second change of the impedance at the location, wherein the first impedance change and the second impedance change are additive, wherein the reflectometry data is indicative of at least one of the first reflectometry signal response or the second reflectometry' signal response,

[0194] Clause 58: The marker of clause 56, wherein the first local condition includes a first temperature and the second local condition includes a second temperature different from the first temperature.

[0195] Clause 59: The marker of any of clauses 56 and 57, wherein the first local condition includes a temperature and the second local condition includes at least one of a humidity or a -water ingress.

[0196] Clause 60: The marker of any one of clauses 34-59, wherein the switch is a first switch including a first resistance modifier configured to change resistance based on a first local condition, the system further including: a second switch configured to bypass the impedance modifier, the second switch including a resistance modifier configured to change resistance based on a second local condition.

[0197] Clause 61: Tire marker of clause 60, wherein the first local condition includes a first temperature and the second local condition includes a second temperature different from the first temperature.

[0198] Clause 62: The marker of clause 60, wherein the first local condition includes a temperature and the second local condition includes at least one of a humidity or a water ingress.

[0199] Clause 63: The marker of any of clauses 60 and 61, wherein the location is a first location, wherein the first local condition is at the first location, wlierein the second local condition is at a second location different from the first location.

[0200] Clause 64: The marker of clause 63, w herein the first location is at a splice and the second location is at the electrical cable at a threshold distance from the splice.

[0201] Clause 65: The marker of any one of clauses 34-64, wherein the impedance modifier includes a dielectric configured to electrically separate a splice shield of a splice and a splice semicon of the splice, w herein the switch is electrically connected betw een the splice shield and the splice semicon.

[0202] Clause 66: Tire marker of any one of clauses 34-65, w herein the impedance modifier includes a dielectric configured to electrically separate a splice shield of a splice and a splice semicon of the splice, wherein the switch is electrically connected bet eo n the splice shield and a conductive material distributed across the splice body and over the splice semicon.

[0203] Clause 67: A method including: injecting, by a sensor, a reflectometry signal onto an electrical cable of an electrical powerline; causing, based on a first condition, a switch to selectively bypass an impedance modifier positioned on or adj cent to the electrical cable at a location along the electrical cable, the impedance modifier configured to cause a reflectometry signal response at the location; acquiring, by the sensor, reflectometr ’ data indicative of the reflectometry' signal response; and determining, by processing circuitry' and based on the reflectometry data, the condition.

[0204] Clause 68: The method of clause 67, wherein the reflectometry' signal response includes a reflection signal indicative of a change of at least one of an impedance or a capacitance at the location.

[0205] Clause 69: The method of clause 68, wherein the impedance modifier is configured to cause the reflectometry' signal response for relatively high frequencies and to not cause the reflectometry' signal response for relatively low frequencies.

[0206] Clause 70: The method of clause 69, wherein the relatively high frequencies correspond to frequencies greater than or equal to 1 kilohertz (kHz), wherein the relatively low frequencies correspond to frequencies less than 1 kHz, wherein the reflectometry data includes at least one of a frequency domain reflectometry' (FDR) data or a time domain reflectometry (TDR) data, and wherein the reflectometry signal response includes at least one of an reflectometry’ signal response or a TDR signal response.

[0207] Clause 71: Tire method of any one of clauses 67-70, further including: changing, by the impedance modifier and when the switch is closed to not bypass the impedance modifier, the impedance at the location by at least one of magnetically coupling or capacitively coupling to the electrical cable at the location,

[0208] Clause 72: The method of any one of clauses 67-71, wherein the reflectometry' signal response is a first reflectometry signal response, wherein the location is a first location, the method further including: causing, by the impedance modifier and when the switch is closed to not bypass the impedance modifier, a second reflectometry' signal response at a second location along the electrical cable.

[0209] Clause 73: The method of clause 72, wherein the second location is along a branch of the electrical cable downstream from the first location relative to the sensor,

[0210] Clause 74: The method of any one of clauses 67-73, wherein the impedance modifier includes at least one of a ferrite bead or a high frequency current transformer.

[0211] Clause 75: The method of any one of clauses 67-74, further including: causing, by the switch, the impedance modifier to couple in parallel to at least one of the electrical cable, a ground connection of the electrical cable, a shield of the electrical cable, or a shield connection of the electrical cable.

[0212] Clause 76: The method of any one of clauses 67-75, wherein the impedance modifier is positioned in contact with or substantially near to the electrical cable.

[0213] Clause 77: The method of any one of clauses 67-76, further including: causing, by the switch, the impedance modifier to magnetically couple to at least one of a ground connection of the electrical cable or a conductor of the electrical cable.

[0214] Clause 78: The method of any one of clauses 67-77, wherein the impedance modifier is positioned circumferentially around a ground connection of the electrical cable.

[0215] Clause 79: Tire method of any one of clauses 67-78, wherein the impedance modifier is positioned circumferentially around a conductor of the electrical cable.

[0216] Clause 78: The method of any one of clauses 67-79, wherein the location is at a node operatively coupled to the electrical cable.

[0217] Clause 79: The method of any one of clauses 67-80, wherein the location is at a splice operatively coupled to the electrical cable.

[0218] Clause 80: The method of any one of clauses 67- 1, wherein the switch includes a manually controlled switch.

[0219] Clause 81: Tlie method of any one of clauses 67-82, wherein the switch includes at least one of an automatically controlled switch, a timed switch, or a remotely controlled switch,

[0220] Clause 82: The method of any one of clauses 67-83, wherein the switch includes an open / close switch.

[0221] Clause 83: The method of any one of clauses 67-84, wherein the switch includes a resistance modifier, wherein causing the reflectometry signal to bypass the impedance modifier includes causing the switch to have a first resistance or a second resistance based on the condition.

[0222] Clause 84: The method of any one of clauses 67-83, wherein the condition includes at least one of a temperature, a humidity, or a water submersion.

[0223] Clause 85: The method of any of clauses 83 through 85, wherein the resistance modifier includes at least one of a bi-metallic strip or a thermistor.[02241 Clause 86: The method of any of clauses 83 through 86, wherein, to change the resistance, the resistance modifier changes from at least one of short to open or open to short.

[0225] Clause 87: Tire method of any one of clauses 67-86, wherein the impedance modifier is a first impedance modifier, wherein the reflectometry signal response is a first reflectometry signal response, wherein the switch is a first switch including a first resistance modifier, the method further including: causing, based on a second condition, a second switch to selectively bypass a second impedance modifier positioned on or adjacent to the electrical cable at the location along the electrical cable, the second impedance modifier configured to cause a second reflectometry signal response at the location; acquiring, by the sensor, the reflectometry data indicative of the second reflectometry signal response; and determining, by processing circuitry and based on the second reflectometry data, the second condition.

[0226] Clause 88: The method of any of clauses 87 and 88, wherein the first reflectometr ’ signal response includes a first reflection signal indicative of a first change of the impedance at the location, wherein the second reflectometry signal response includes a second reflection signal indicative of a second change of the impedance at the location, wherein the first impedance change and the second impedance change are additive.

[0227] Clause 89: Tlie method of any of clauses 87 through 89, wherein the first condition includes a temperature of the switch being less than or equal to a first threshold temperature, wherein the second condition includes the temperature of the switch being less than or equal to a second threshold temperature.

[0228] Clause 90: The method of any of clauses 87 through 90, wherein the first condition is based on a temperature, w herein the second condition is based on at least one of a humidity or a -water ingress.

[0229] Clause 91: Tlie method of any one of clauses 67-90, wherein the switch is a first switch including a first resistance modifier, the method further including: causing, based on a second condition, a second switch to selectively bypass the impedance modifier.

[0230] Clause 92: The method of any of clauses 91 and 92, wherein the first condition includes a temperature of the sw itch being less than or equal to a first thresholdtemperature, wherein the second condition includes the temperature of the switch being less than or equal to a second threshold temperature.[0231 Clause 93: The method of any of clauses 91 through 93, wherein the first condition is based on a temperature, wherein the second condition is based on at least one of a humidity or a water ingress,

[0232] Clause 94: The method of any of clauses 91 through 94, wherein the location is a first location, wherein the first condition is at the first location, wherein the second condition is at a second location different from the first location.

[0233] Clause 95: The method of any of clauses 94 and 95, wherein the first location is at a splice and the second location is at the electrical cable at a threshold distance from the splice.

[0234] Clause 96: The method of any one of clauses 67-95, wherein the impedance modifier includes a dielectric configured to electrically separate a splice shield of a splice and a splice semicon of the splice, wherein the switch is electrically connected between the splice shield and the splice semicon.

[0235] Clause 97: The method of any one of clauses 67-96, wherein the impedance modifier includes a dielectric configured to electrically separate a splice shield of a splice and a splice semicon of the splice, wherein the switch is electrically connected between the splice shield and a conductive material distributed across the splice body and over the splice semi con.Clause 98: A system configured to monitor an electric powerline comprising an electrical cable, the system comprising: a sensor configured to acquire a reflectometry data through the electrical cable; and an impedance modifier comprising a ferrite material and positioned on or adjacent to the electrical cable at a location along the electrical cable, the impedance modifier configured to cause a reflectometry signal response at the location.

[0236] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A system configured to monitor an electric powerline comprising an electrical cable, the system comprising:a sensor configured to acquire a reflectometry data through the electrical cable; an impedance modifier positioned on or adjacent to the electrical cable at a location along the electrical cable, the impedance modifier configured to cause a reflectometry signal response at the location; anda switch configured to selectively bypass the impedance modifier.

2. The system of claim 1, wherein the reflectometry signal response comprises a reflection signal indicative of a change of at least one of an impedance or a capacitance at the location.

3. lire system of claim 2, wherein the impedance modifier is configured to cause the reflectometry signal response for relatively high frequencies and to not cause the reflectometry signal response for relatively low frequencies.

4. The system of claim 3, wherein the relatively high frequencies correspond to frequencies greater than or equal to 1 kilohertz (kHz), wherein the relatively low' frequencies correspond to frequencies less than 1 kHz,wherein the reflectometry data comprises at least one of a frequency domain reflectometry (FDR) data or a time domain reflectometry (TDR) data, andwherein the reflectometry signal response comprises at least one of an FDR signal response or a TDR signal response.

5. The system of claim 1, wherein the impedance modifier is configured to change the impedance at the location by at least one of magnetically coupling or capacitively coupling to the electrical cable at the location.

6. The system of claim 1, wherein the reflectometry signal response is a first reflectometry signal response, wherein the location is a first location, wherein the impedance modifier is configured to change a second reflectometry signal response at a second location along the electrical cable.

7. The system of claim 6, wherein the second location is along a branch of the electrical cable downstream from the first location relative to the sensor.

8. The system of claim 1, wherein the impedance modifier comprises at least one of a ferrite bead or a high frequency current transformer.

9. The system of claim 1, wherein the impedance modifier is coupled in parallel to at least one of the electrical cable, a ground connection of tire electrical cable, a shield of the electrical cable, or a shield connection of the electrical cable.

10. The system of claim 1, wherein the impedance modifier is positioned in contact with or substantially near to the electrical cable.

11. The system of claim 1, wherein the impedance modifier is configured to magnetically couple to at least one of a ground connection of the electrical cable or a conductor of the electrical cable.

12. The system of claim 1, wherein the impedance modifier is positioned circumferentially around a ground connection of the electrical cable.

13. The system of claim 1, wherein the impedance modifier is positioned circumferentially around a conductor of the electrical cable.

14. lire system of claim 1, wherein the location is at a node operatively coupled to the electrical cable.

15. The system of claim 1, wherein the location is at a splice operatively coupled to the electrical cable.

16. The system of claim 1, wherein the switch comprises a manually controlled switch.

17. The system of claim 1, wherein the switch comprises at least one of an automatically controlled switch, a timed switch, or a remotely controlled switch.

18. The system of claim 1, wherein the switch comprises an open / close switch or a resistance modifier.

19. The system of claim 1, wherein the switch composes a resistance modifier configured to change resistance based on a local condition.

20. lire system of claim 19, wherein the local condition comprises at least one of a temperature, a humidity, or a water submersion.

21. The system of claim 19, w'herein the resistance modifier comprises at least one of a bi-metallic strip or a thermistor.

22. The system of claim 19, wherein the resistance modifier is configured to change the resistance by changing from at least one of short to open or open to short.

23. The system of claim 1, wherein the impedance modifier is a first impedance modifier, wherein the reflectometry signal response is a first reflectometry signal response, wherein the switch is a first switch comprising a first resistance modifier configured to change resistance based on a first local condition, the system further comprising:a second impedance modifier positioned on or adjacent to the electrical cable at the location along the electrical cable, the second impedance modifier configured to cause a second reflectometry signal response at the location; anda second switch configured to bypass the second impedance modifier, the second switch comprising a resistance modifier configured to change resistance based on a second local condition.

24. The system of claim 23, wherein the first reflectometry signal response composes a first reflection signal indicative of a first change of the impedance at the location, wherein the second reflectometry signal response comprises a second reflection signal indicative of a second change of the impedance at the location, wherein the first impedance change and the second impedance change are additive, wherein the reflectometry data is indicative of at least one of the first reflectometry signal response or the second reflectometry signal response.

25. The system of claim 23, wherein the first local condition comprises a first temperature and the second local condition comprises a second temperature different from the first temperature.

26. The system of claim 23, wherein the first local condition comprises a temperature and the second local condition comprises at least one of a humidity or a water ingress.

27. The system of claim 1, wherein the switch is a first switch comprising a first resistance modifier configured to change resistance based on a first local condition, the system further comprising:a second switch configured to bypass the impedance modifier, the second switch comprising a resistance modifier configured to change resistance based on a second local condition.

28. The system of claim 27, wherein the first local condition comprises a first temperature and the second local condition comprises a second temperature different from the first temperature.

29. The system of claim 27, wherein the first local condition comprises a temperature and the second local condition comprises at least one of a humidity or a water ingress.

30. The system of claim 27, wherein the location is a first location, wherein the first local condition is at the first location, wherein the second local condition is at a second location different from the first location.

31. The system of claim 30, wherein the first location is at a splice and the second location is at the electrical cable at a threshold distance from the splice.

32. The system of claim 1, wherein the impedance modifier comprises a dielectric configured to electrically separate a splice shield of a splice and a splice semicon of the splice, wherein the switch is electrically connected between the splice shield and the splice semicon.

33. The system of claim 1, wherein the impedance modifier comprises a dielectric configured to electrically separate a splice shield of a splice and a splice semicon of the splice, wherein the switch is electrically connected between the splice shield and a conductive material distributed across the splice body and over the splice semicon.

34. A marker of an electric powerline comprising an electrical cable, the marker comprising:an impedance modifier positioned on or adjacent to the electrical cable at a location along the electrical cable, the impedance modifier configured to cause a reflectometry signal response at the location; anda switch configured to selectively bypass the impedance modifier.

35. The marker of claim 34, wherein the FDR signal response comprises a reflection signal indicative of a change of at least one of an impedance or a capacitance at the location.

36. The marker of claim 35, wherein the impedance modifier is configured to cause the FDR signal response for relatively high frequencies and to not cause the FDR signal response for relatively low frequencies.

37. The marker of claim 36, wherein the relatively high frequencies correspond to frequencies greater than or equal to 1 kilohertz (kHz), wherein the relatively low frequencies correspond to frequencies less than 1 kHz,wherein the reflectometry data comprises at least one of a frequency domain reflectometry (FDR) data or a time domain reflectometry (TDR) data, andwherein the reflectometry signal response comprises at least one of an FDR signal response or a TDR signal response.

38. The marker of claim 34, wherein the impedance modifier is configured to change the impedance at the location by at least one of magnetically coupling or capacitively coupling to the electrical cable at the location.

39. The marker of claim 34, wherein the reflectometry signal response is a first reflectometry signal response, wherein the location is a first location, wherein the impedance modifier is configured to change a second reflectometry signal response at a second location along the electrical cable.

40. The marker of claim 39, w herein the second location is along a branch of the electrical cable downstream from the first location relative to the sensor.

41. The marker of claim 34, wherein the impedance modifier comprises at least one of a ferrite bead or a high frequency current transformer.

42. The marker of claim 34, wherein the impedance modifier is coupled in parallel to at least one of the electrical cable, a ground connection of the electrical cable, a shield of the electrical cable, or a shield connection of the electrical cable.

43. The marker of claim 34, wherein the impedance modifier is positioned in contact with or substantially near to the electrical cable.

44. The marker of claim 34, wherein the impedance modifier is configured to magnetically couple to at least one of a ground connection of the electrical cable or a conductor of the electrical cable.

45. The marker of claim 34, wherein the impedance modifier is positioned circumferentially around a ground connection of the electrical cable.

46. The marker of claim 34, wherein the impedance modifier is positioned circumferentially around a conductor of the electrical cable.

47. The marker of claim 34, wherein the location is at a node operatively coupled to the electrical cable.

48. The marker of claim 34, wherein the location is at a splice operatively coupled to the electrical cable.

49. The marker of claim 34, wherein the switch comprises a manually controlled switch.

50. The marker of claim 34, wherein the switch comprises at least one of an automatically controlled switch, a timed switch, or a remotely controlled switch.

51. The marker of claim 34, wherein the switch comprises an open / close switch or a resistance modifier.

52. The marker of claim 34, wherein the switch comprises a resistance modifier configured to change resistance based on a local condition.

53. The marker of claim 52, wherein the local condition comprises at least one of a temperature, a humidity, or a water submersion,54. The marker of claim 52, wherein the resistance modifier comprises at least one of a bi-metallic strip or a thermistor.

55. The marker of claim 52, wherein the resistance modifier is configured to change the resistance by changing from at least one of short to open or open to short.

56. The marker of claim 34, wherein the impedance modifier is a first impedance modifier, wherein the reflectometry signal response is a first reflectometry signal response, wherein the switch is a first switch comprising a first resistance modifier configured to change resistance based on a first local condition, the system further comprising:a second impedance modifier positioned on or adjacent to the electrical cable at the location along the electrical cable, the second impedance modifier configured to cause a second reflectometry signal response at the location; anda second switch configured to bypass the second impedance modifier, the second switch comprising a resistance modifier configured to change resistance based on a second local condition.

57. The marker of claim 56, wherein the first reflectometry signal response comprises a first reflection signal indicative of a first change of the impedance at the location, wherein the second reflectometry signal response comprises a second reflection signal indicative of a second change of the impedance at the location, wherein the first impedance change and the second impedance change are additive, wherein the reflectometry data is indicative of at least one of the first reflectometry signal response or the second reflectometry signal response.

58. The marker of claim 56, wherein the first local condition comprises a first temperature and the second local condition comprises a second temperature different from the first temperature.

59. The marker of claim 56, wherein the first local condition comprises a temperature and the second local condition comprises at least one of a humidity or a water ingress.

60. The marker of claim 34, wherein the switch is a first switch comprising a first resistance modifier configured to change resistance based on a first local condition, the system further comprising:a second switch configured to bypass the impedance modifier, the second switch comprising a resistance modifier configured to change resistance based on a second local condition.

61. The marker of claim 60, wherein the first local condition comprises a first temperature and the second local condition comprises a second temperature different from the first temperature.

62. The marker of claim 60, wherein the first local condition comprises a temperature and the second local condition comprises at least one of a humidity or a water ingress.

63. The marker of claim 60, wherein the location is a first location, wherein the first local condition is at the first location, wherein the second local condition is at a second location different from the first location.

64. The marker of claim 63, wherein the first location is at a splice and the second location is at the electrical cable at a threshold distance from the splice.

65. The marker of claim 34, wherein the impedance modifier comprises a dielectric configured to electrically separate a splice shield of a splice and a splice semicon of the splice, wherein the switch is electrically connected between the splice shield and the splice semicon.

66. The marker of claim 34, wherein the impedance modifier comprises a dielectric configured to electrically separate a splice shield of a splice and a splice semicon of the splice, wherein the switch is electrically connected between the splice shield and a conductive material distributed across the splice body and over the splice semicon.

67. A method comprising:injecting, by a sensor, a reflectometry signal onto an electrical cable of an electrical powerline;causing, based on a first condition, a switch to selectively bypass an impedance modifier positioned on or adjacent to the electrical cable at a location along the electrical cable, the impedance modifier configured to cause a reflectometry’ signal response at the location;acquiring, by the sensor, reflectometry data indicative of the reflectometry signal response; anddetermining, by processing circuitry’ and based on the reflectometry’ data, the condition.

68. The method of claim 67, wherein the reflectometry signal response comprises a reflection signal indicative of a change of at least one of an impedance or a capacitance at the location.

69. The method of claim 68, wherein the impedance modifier is configured to cause the reflectometry signal response for relatively high frequencies and to not cause the reflectometry signal response for relatively low frequencies.

70. The method of claim 69, wherein the relatively high frequencies correspond to frequencies greater than or equal to 1 kilohertz (kHz), wherein the relatively low frequencies correspond to frequencies less than 1 kHz,wherein the reflectometry data comprises at least one of a frequency domain reflectometry (FDR) data or a time domain reflectometry’ (TDR) data, andwherein the reflectometry signal response comprises at least one of an FDR signal response or a TDR signal response.

71. The method of claim 67, further comprising:changing, by the impedance modifier and when the switch is closed to not bypass the impedance modifier, the impedance at the location by at least one of magnetically coupling or capacitively coupling to the electrical cable at the location,72. The method of claim 67, wherein the reflectometry signal response is a first reflectometry signal response, wherein the location is a first location, the method further comprising:causing, by the impedance modifier and when the switch is closed to not bypass the impedance modifier, a second reflectometry signal response at a second location along the electrical cable.

73. The method of claim 72, wherein the second location is along a branch of the electrical cable downstream from the first location relative to the sensor.

74. The method of claim 67, wherein the impedance modifier comprises at least one of a ferrite bead or a high frequency current transformer.

75. The method of claim 67, further comprising:causing, by the sw itch, the impedance modifier to couple in parallel to at least one of the electrical cable, a ground connection of the electrical cable, a shield of the electrical cable, or a shield connection of the electrical cable76. The method of claim 67, wherein the impedance modifier is positioned in contact with or substantially near to the electrical cable.

77. The method of claim 67, further comprising:causing, by the switch, the impedance modifier to magnetically couple to at least one of a ground connection of the electrical cable or a conductor of the electrical cable.

78. The method of claim 67, wherein the impedance modifier is positioned circumferentially around a ground connection of the electrical cable.

79. The method of claim 67, wherein the impedance modifier is positioned circumferentially around a conductor of the electrical cable.

78. The method of claim 67, wherein the location is at a node operatively coupled to the electrical cable.

79. The method of claim 67, wherein the location is at a splice operatively coupled to the electrical cable.

80. The method of claim 67, wherein the switch comprises a manually controlled switch.

81. The method of claim 67, wherein the switch comprises at least one of an automatically controlled switch, a timed switch, or a remotely controlled switch.

82. The method of claim 67, wherein the switch comprises an open / close switch.

83. The method of claim 67, wherein the switch comprises a resistance modifier, wherein causing the reflectometry signal to bypass the impedance modifier comprises causing the switch to have a first resistance or a second resistance based on the condition.

84. The method of claim 67, wherein the condition comprises at least one of a temperature, a humidity, or a water submersion.

85. The method of claim 83, wherein the resistance modifier comprises at least one of a bi-metallic strip or a thermistor,86. The method of claim 83, wherein, to change the resistance, the resistance modifier changes from at least one of short to open or open to short.

87. The method of claim 67, wherein the impedance modifier is a first impedance modifier, wherein the reflectometry signal response is a first reflectometry signal response, wherein the switch is a first switch comprising a first resistance modifier, the method further comprising:causing, based on a second condition, a second sw itch to selectively bypass a second impedance modifier positioned on or adjacent to the electrical cable at the location along the electrical cable, the second impedance modifier configured to cause a second reflectometry signal response at tire location;acquiring, by the sensor, the reflectometry data indicative of the second reflectometry signal response; anddetermining, by processing circuitry and based on the second reflectometry data, the second condition.

88. The method of claim 87, wherein the first reflectometry signal response comprises a first reflection signal indicative of a first change of the impedance at the location, wherein the second reflectometry signal response comprises a second reflection signal indicative of a second change of the impedance at the location, wherein the first impedance change and the second impedance change are additive.

89. The method of claim 87, wherein the first condition comprises a temperature of the switch being less than or equal to a first threshold temperature, wherein the second condition comprises the temperature of the switch being less than or equal to a second threshold temperature.

90. The method of claim 87, wherein the first condition is based on a temperature, wherein the second condition is based on at least one of a humidity or a water ingress.

91. The method of claim 67, wherein the switch is a first switch comprising a first resistance modifier, the method further comprising:causing, based on a second condition, a second switch to selectively bypass the impedance modifier.

92. The method of claim 91, wherein the first condition comprises a temperature of the switch being less than or equal to a first threshold temperature, wherein the second condition comprises the temperature of the switch being less than or equal to a second threshold temperature.

93. The method of claim 91, wherein the first condition is based on a temperature, wherein the second condition is based on at least one of a humidity or a water ingress.

94. The method of claim 91, wherein the location is a first location, wherein the first condition is at the first location, wherein the second condition is at a second location different from the first location.

95. The method of claim 94, wherein the first location is at a splice and the second location is at the electrical cable at a threshold distance from the splice.

96. The method of claim 67, wherein the impedance modifier comprises a dielectric configured to electrically separate a splice shield of a splice and a splice semicon of the splice, wherein the switch is electrically connected between the splice shield and the splice semicon.

97. The method of claim 67, wherein the impedance modifier comprises a dielectric configured to electrically separate a splice shield of a splice and a splice semicon of the splice, wherein the switch is electrically connected between the splice shield and a conductive material distributed across the splice body and over the splice semicon.

98. A system configured to monitor an electric powerline comprising an electrical cable, the system comprising:a sensor configured to acquire a reflectometry data through the electrical cable; and an impedance modifier comprising a ferrite material and positioned on or adjacent to the electrical cable at a location along the electrical cable, the impedance modifier configured to cause a reflectometry' signal response at the location.

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