Electric power quality and event analyzer

Abstract

A method includes: delivering electrical power from an electrical power system to a device for powering the device; receiving, at transient recorder equipment, current measurements and voltage measurements from sensors located in the electrical power system; triggering, via the transient recorder equipment, a digital data recording of the current measurements and the voltage measurements taken over a period of time; communicating the digital data recording to a control system communicatively coupled to the transient recorder equipment; comparing, via a pattern recognition / analysis component of the control system, the digital data recording to an expected time-based pattern of current and voltage; and outputting an alarm or alert based on the digital data recording deviating from the expected time-based pattern.

Description

ELECTRIC POWER QUALITY AND EVENT ANALYZERTECHNICAL FIELD

[0001] The present invention is directed to methods and devices for monitoring electric power systems, and more particularly, to a power monitor and analyzer (PMA) system that provides electric power quality and event analysis for electric power systems.BACKGROUND

[0002] Electric power systems are used to provide electrical power necessary to operate various types of equipment. As an example, in the field of subsea oil and gas production, electric power systems are used to provide electrical power to operate subsea devices, such as pumps and compressors, among other types of equipment. Power monitoring systems are used to monitor the operations of electric power systems based on detected voltage, current, and / or other sensor measurements taken from the power system. Conventional power monitoring systems act as a diagnostic tool for monitoring the operation of rotating electric power equipment that operates at a fundamental frequency (e.g., 50 or 60 Hz). Although the power monitoring systems can collect and display higher frequency data from the sensor signals, the systems are limited in bandwidth and cannot make many, if any, real-time calculations based on the high frequency portions of sensor data. As such, existing power monitoring systems do not provide continuous, high frequency monitoring of their electric power systems. Instead, the systems rely on programmable triggers, which are limited in function, for taking occasional or intermittent samples of the data for further analysis. Furthermore, power monitoring systems usually require the interpretation of these high frequency data samples by qualified personnel, which can take time and yield inconsistent results depending on who is reviewing the data.

[0003] The issues with existing power monitoring systems are compounded when they are used to monitor power supplies that are non-sinusoidal, such as adjustable speed drives (ASDs) operating above fundamental frequency. Particularly in fields like subsea exploration, where an ASD may be separated from the device it is powering by kilometers of cabling, both regularly occurring noise and unusual noise in the electrical signals (which may be indicative of an issue) can become hard to distinguish from the normal operation of the ASD.

[0004] As power electronic-based power supplies become more common across industries, there is a growing need for electric power monitoring systems that can provide continuous multifunction measurements of operations involving power supplied by power electronic sources such as ASDs.SUMMARY

[0005] In accordance with an aspects of the present disclosure, a method includes: delivering electrical power from an electrical power system to a device for powering the device; receiving, at transient recorder equipment, current measurements and voltage measurements from sensors located in the electrical power system; triggering, via the transient recorder equipment, a digital data recording of the current measurements and the voltage measurements taken over a period of time; communicating the digital data recording to a control system communicatively coupled to the transient recorder equipment; comparing, via a pattern recognition / analysis component of the control system, the digital data recording to an expected time-based pattern of current and voltage; and outputting an alarm or alert based on the digital data recording deviating from the expected time-based pattern.

[0006] In accordance with another aspect of the present disclosure, a system includes: an electrical power system configured to deliver electrical power to a device for powering the device; at least one current sensor and at least one voltage sensor, each sensor located in the electrical power system; transient recorder equipment communicatively coupled to the at least one current sensor and the at least one voltage sensor; and a control system communicatively coupled to the transient recorder equipment, wherein the transient recorder equipment includes multiple components configured to: receive current measurements from the at least one current sensor and voltage measurements from the at least one voltage sensor; trigger a digital data recording of the current measurements and the voltage measurements taken over a period of time; and communicate the digital data recording to the control system, and wherein the control system is configured to: compare the digital data recording to an expected time-based pattern of current and voltage; and output an alarm or alert based on the digital data recording deviating from the expected time-based pattern.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The drawings illustrate only example embodiments and are therefore not to be considered limiting in scope, as the example embodiments may admit to other equally effective embodiments. The elements and features shown in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the example embodiments. Additionally, certain dimensions or positions may be exaggerated to help visually convey such principles.

[0008] FIG. 1 is a schematic block diagram illustrating an example system including: an electrical power system used to power a subsea device; and a power monitor and analyzer (PMA) system, in accordance with an embodiment of the present techniques.

[0009] FIG. 2 is a detailed schematic diagram illustrating an example system including: an electrical power system used to power a subsea device; and a PMA system, in accordance with an embodiment of the present techniques.

[0010] FIG. 3 is a schematic block diagram illustrating an example PMA system, in accordance with an embodiment of the present techniques.

[0011] FIG. 4 is a process flow diagram illustrating a method for monitoring an electrical power system and monitoring events in the electrical power system, in accordance with an embodiment of the present disclosure.DETAILED DESCRIPTION OF THE DRAWINGS

[0012] The example embodiments discussed herein are directed to systems, apparatus, and methods related to monitoring and analyzing sensor data indicative of the operation of an electrical power system. Such electrical power systems may include conventional rotational power systems that operate sinusoidally at fundamental frequency (50 or 60 Hz) or power electronic-based power systems that can operate at different frequencies, such as adjustable speed drives (ASDs). The electrical power systems may be those used to operate one or more subsea devices, such as pumps or compressors used during operations of subsea exploration, development, and / or production of a subterranean formation. For example, the electrical power systems may be used to power one or more subsea devices used during drilling, completion, or production operations involving one or more subsea wells. The subsea devices may include one or more of subsea boosting equipment (e.g., pumps, compressors), all-electric subsea controls (e.g., valves, actuators, etc.), a subsea battery system, or a remote surface facility (e.g., semisubmersible platform, etc.). The electrical power systems may include one or more of a power drive system, a subsea power transmission system, or a subsea power distribution system. In some embodiments, the electrical power is delivered from the electrical power system to the device via an insulated cable having a length greater than 5 km.

[0013] The disclosed systems and methods may aid in the monitoring and analysis of subsea electric power circuits, especially those driven by ASDs and long (e.g., greater than 5 km) transmission cables. Such a system may provide insight into the conditions in facilities subsea and aid in the root cause analysis of any electrical failures. However, the system may be applied to other parts of the power system that are not subsea.

[0014] While the disclosed power monitor and analyzer (PMA) system is shown and described in the context of its connection to an electric power system providing power to subsea equipment, a person having ordinary skill in the art will recognize that the PMA system may be used with other electric power systems as well, such as those used for powering equipment above sea level including offshore and onshore installations and others.

[0015] The use of the terms "about", “approximately”, and similar terms applies to all numeric values, whether or not explicitly indicated. These terms generally refer to a range of numbers that one of ordinary skill in the art would consider as a reasonable amount of deviation to the recited numeric values (i.e., having the equivalent function or result). For example, this term may be construed as including a deviation of ±10 percent of the given numeric value provided such a deviation does not alter the end function or result of the value. Therefore, a value of about 1% may be construed to be a range from 0.9% to 1.1%. Furthermore, a range may be construed to include the start and the end of the range. For example, a range of 10% to 20% (i.e., range of 10%-20%) includes 10% and also includes 20%, and includes percentages in between 10% and 20%, unless explicitly stated otherwise herein. Similarly, a range of between 10% and 20% (i.e., range between 10% - 20%) includes 10% and also includes 20%, and includes percentages in between 10% and 20%, unless explicitly stated otherwise herein.

[0016] It is understood that when combinations, subsets, groups, etc. of elements are disclosed (e.g., combinations of components in a composition, or combinations of steps in a method), that while specific reference of each of the various individual and collective combinations and permutations of these elements may not be explicitly disclosed, each is specifically contemplated and described herein. By way of example, if an item is described herein as including a component of type A, a component of type B, a component of type C, or any combination thereof, it is understood that this phrase describes all of the various individual and collective combinations and permutations of these components. For example, in some embodiments, the item described by this phrase could include only a component of type A. In some embodiments, the item described by this phrase could include only a component of type B. In some embodiments, the item described by this phrase could include only a component of type C. In some embodiments, the item described by this phrase could include a component of type A and a component of type B. In some embodiments, the item described by this phrase could include a component of type A and a component of type C. In some embodiments, the item described by this phrase could include a component of type B and a component of type C. In some embodiments, the item described by this phrase could include a component of type A, a component of type B, and a component of type C. In some embodiments, the item described by this phrase could include two or more componentsof type A (e.g., Al and A2). In some embodiments, the item described by this phrase could include two or more components of type B (e.g., Bl and B2). In some embodiments, the item described by this phrase could include two or more components of type C (e.g., Cl and C2). In some embodiments, the item described by this phrase could include two or more of a first component (e.g., two or more components of type A (Al and A2)), optionally one or more of a second component (e.g., optionally one or more components of type B), and optionally one or more of a third component (e.g., optionally one or more components of type C). In some embodiments, the item described by this phrase could include two or more of a first component (e.g., two or more components of type B (B 1 and B2)), optionally one or more of a second component (e.g., optionally one or more components of type A), and optionally one or more of a third component (e.g., optionally one or more components of type C). In some embodiments, the item described by this phrase could include two or more of a first component (e.g., two or more components of type C (Cl and C2)), optionally one or more of a second component (e.g., optionally one or more components of type A), and optionally one or more of a third component (e.g., optionally one or more components of type B).

[0017] If a component of a figure is described but not expressly shown or labeled in that figure, the label used for a corresponding component in another figure may be inferred to that component. Conversely, if a component in a figure is labeled but not described, the description for such component may be substantially the same as the description for the corresponding component in another figure. For any figure shown and described herein, one or more of the components may be omitted, added, repeated, and / or substituted. Accordingly, embodiments shown in a particular figure should not be considered limited to the specific arrangements of components shown in such figure.

[0018] Further, a statement that a particular embodiment (e.g., as shown in a figure herein) does not have a particular feature or component does not mean, unless expressly stated, that such embodiment is not capable of having such feature or component. For example, for purposes of present or future claims herein, a feature or component that is described as not being included in an example embodiment shown in one or more particular drawings is capable of being included in one or more claims that correspond to such one or more particular drawings herein.

[0019] Terms such as “first”, “second”, “primary,” “secondary,” “above”, “below”, “inner”, “outer”, “distal”, “proximal”, “end”, “top”, “bottom”, “upper”, “lower”, “side”, “left”, “right”, “front”, “rear”, and “within”, when present, are used merely to distinguish one component (or part of a component or state of a component) from another. This list of terms is not exclusive. Such terms are not meant to denote a preference or a particular orientation, and they are not meant tolimit embodiments of earth penetrating tools. In the following detailed description of the example embodiments, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0020] FIG. 1 is a block diagram illustrating an example system 100 including an electrical power system 102 used to power a subsea device 104 and a PMA system 106 for monitoring the electrical power system 102. Although only one electrical power system 102 and one subsea device 104 are shown, the PMA system 106 may be used to monitor multiple electrical power systems 102 each being used to operate a different subsea device 104. As illustrated, a portion of the electrical power system 102 may be located at a surface location 108, while the device 104 being operated via power output by the power system 102 is located subsea. Power is transmitted from the surface portion of the power system 102 to the subsea device 104 via a cable 110 (which is part of the power system 102). The cable 110 may be part of a subsea umbilical. In other embodiments, the electrical power system 102 may be located entirely subsea, closer to the device 104 it is operating. As illustrated, the PMA system 106 may be located above the surface of the water.

[0021] In one example, the power system 102 may be supplied by or include traditional power generation (e.g., rotating equipment), where the output is sinusoidal at a fundamental frequency. In another example, the power system 102 may be supplied by or include power electronic equipment such as adjustable speed drives (ASDs), where the output may be non-sinusoidal and of varying frequency.

[0022] The PMA system 106 generally includes at least two components: transient recorder equipment 112 and a separate control system 114 including additional system software. As illustrated, the transient recorder equipment 112 may be located at the surface location 108 of the installation, near a surface portion of the electrical power system 102. The control system 114 may be located at a different location remote from the installation. For example, the control system 114 may be located at an onshore facility. The control system 114 may be communicatively coupled to the transient recorder equipment 112 (e.g., via a wired connection). In other embodiments, the control system 114 may be located at the installation along with the transient recorder equipment 112. In such embodiments, the transient recorder equipment 112 and the control system 114 may be communicatively coupled via a wired connection and / or the systems may be packaged together.

[0023] The system 100 may further include one or more authorized systems 117 located remote from the PMA system 106. The authorized systems 117 may include authorized systems external to the PMA system 106 that are configured to provide further analysis and / or to output analysisresults, alerts / alarms, statuses, and / or other information from the PMA system 106 to one or more authorized users. As shown, the authorized systems 117 may be located remote from the installation having the transient recorder equipment 112 and remote from the control system 114 as well. The authorized systems 117 may be communicatively coupled to one or both of the transient recorder equipment 112 and the control system 114. In other embodiments, one or more authorized systems 117 may be located near the control system 114. In such embodiments, the authorized systems 117 and the control system 114 may be communicatively coupled via a wired connection and / or the systems may be packaged together. In still other embodiments, the authorized systems 117 may be located at the installation as well as the transient recorder equipment 112 and / or the control system 114.

[0024] Multiple sensors 118 are located throughout the electrical power system 102. These sensors 118 may include passive sensors, active sensors, or a combination thereof. The sensors 118 may include current, voltage, temperature, vibration, active power, reactive power, acceleration, motion, impedance, and / or other types of sensors. The sensors 118 may include one or more components that output data indicative of a status of the power system 102, such as a frequency at which the drive is operating. As illustrated, the sensors 118 may be communicatively coupled to the transient recorder equipment 112, e.g., via multiple channels.

[0025] The transient recorder equipment 112 may include one or more processors 120 and at least one memory 122. The memory 122 may be a non-transitory computer-readable medium storing instructions that, when executed by the one or more processors 120, cause the transient recorder equipment 112 to perform one or more methods or steps in accordance with present embodiments. The transient recorder equipment 112 may comprise hardware, firmware, software, or a combination thereof, as shown in FIG. 3.

[0026] The control system 114 may include one or more processors 124 and at least one memory 126. The memory 126 may be a non-transitory computer-readable medium storing instructions that, when executed by the one or more processors 124, cause the control system 114 to perform one or more methods or steps in accordance with present embodiments. The control system 114 may comprise software, as shown in FIG. 3.

[0027] In embodiments where the transient recorder equipment 112 and the control system 114 are integrated into one component, the processors 120 / 124 may be separate or integrated components within the PMA system 106, and the memories 122 / 126 may be separate or integrated components within the PMA system 106.

[0028] The PMA system 106 described herein provides continuous monitoring of waveform variables and uses pattern recognition and analysis to monitor the conditions of the electrical powersystem 102. The PMA system 106 may provide autonomous decision making regarding when to provide warnings or alarms. The PMA system 106 may be configured to alert personnel of abnormal transient conditions that could result in equipment degradation and eventual failure of the power system 102. The PMA system 106 may help in analyzing power system events and diagnosing the root cause of transients in the data that could otherwise affect performance of the transmission and distribution facilities.

[0029] The PMA system 106 reads currents and voltages at one or more points in the power system 102 and converts them to digital form. The PMA system 106 then calculates parameters and derives waveforms based on these inputs in a timeline synchronized with the raw data. The disclosed PMA system 106 may provide calculations that account for a higher frequency bandwidth and larger frequency variations than existing power monitoring systems. In addition, certain parameters may be calculated in real time or near-real time to provide internal triggering of highspeed recordings for further analysis. The functions used in these calculations may be included in hardware, firmware, or software depending on the real time need for a given calculation. Calculated time-based variables may include circuit impedance, harmonic content, symmetrical components, and intra-phase comparison of these values.

[0030] Non-sinusoidal waveforms, especially those produced by ASDs, are complex and have high frequency components that require fast sampling rates. The disclosed PMA system 106 may incorporate pattern recognition and machine learning to discern what are normal versus abnormal patterns in the waveforms. The information may then be used to provide warnings and alarms and to troubleshoot faults. Non-electrical parameters (e.g., temperature or motion) may also be included for correlation with the other detected or calculated parameters within the PMA system 106. Based on these analyses, the PMA system 106 may be able to predict issues with the power system 102 before they lead to failures within the power system 102. The PMA system 106 may output alerts or warnings that prompt a user to perform maintenance or repairs on the power system 102 and then, upon completion of the maintenance or repairs, determine whether the issues indicated by the previous data analysis were resolved. The PMA system 106 may be used to determine what patterns indicate a fault in the system or progression of the system toward a fault. In particular, the PMA system 106 may compare patterns produced in the sensor data or internally calculated variables over time while the subsea device 104 (e.g., a pump) runs at the same speed. The PMA system 106 may regularly track the patterns in the sensor data and other variables over a predetermined length of time (e.g., one year) to determine a baseline, expected pattern for the power system 102.

[0031] FIG. 2 illustrates an electrical diagram of an example system 200 including the electrical power system 102 used to power the subsea device 104 and the PMA system 106 for monitoring the electrical power system 102. As shown in FIG. 2, the electrical power system 102 may include a switchgear 202 with feeder breaker, a filter 204 (e.g., harmonic filter), a step-up transformer 206, a topside umbilical termination 208, a subsea power umbilical 210, a subsea umbilical termination 212, and a step-down transformer 214 leading to the subsea load (i.e., subsea device 104). The electrical power may be provided via traditional rotating element(s) or power electronics (e.g., an adjustable speed drive (ASD)). The switchgear 202 controls the output of electrical power from such power generation equipment toward the filter 204, which filters the alternating current (AC) output toward the transformer 206 and beyond. The transformer 206 steps up the AC voltage to the topside umbilical termination 208. A subsea umbilical 210 (having transmission cable 110) is coupled between the topside umbilical termination 208 and the subsea umbilical termination 212 and is configured to transmit AC to power the subsea load (i.e., subsea device 104). Between the subsea umbilical termination 212 and the subsea device 104 is a subsea step-down transformer 214 to reduce the AC voltage to a level acceptable for the subsea device 104. The subsea device 104 may be a motor driven load, such as a pump or compressor. It should be noted that different elements or combinations of elements may be used in the electrical power system 102 / transmission equipment in other embodiments.

[0032] As illustrated, the electrical power system 102 may include four sensors 118A-D used to measure properties of the electrical power system 102. The sensors 118A-D may include two voltage sensors 118 A and 118D and two current sensors 118B and 118C. One set of voltage / current sensors 118A and 118B is located between the filter 204 and the step-up transformer 206, and the other set of voltage / current sensors 118C and 118D is located between the transformer 206 and the topside umbilical termination 208. The PMA system 106 may be communicatively coupled to and receive sensor signals from the sensors 118A-D, as shown. Other number, types, locations, and arrangements of sensors 118 may be present in the electrical power system 102 and communicatively coupled to the PMA system 106 in other embodiments.

[0033] The PMA system 106 may receive other inputs as well. For example, the PMA system 106 may receive a clock sync signal 216 and one or more system status signals 218 (both described below with reference to FIG. 3). The PMA system 106 may also be configured to receive one or more external trigger signals, such as a local event trigger signal 220 and / or a remote trigger signals 222. The local and remote triggers may activate high speed sampling within the PMA system 106. An example of a remote trigger signal 222 may be a controller that triggers high speed recordingduring an upset condition. The PMA system 106, as shown, may output data or control signals to a local server or power management system 224.

[0034] A detailed description of the PMA system 106 will now be provided. FIG. 3 is a block diagram illustrating an example of the PMA system 106. Different parts and functions of the PMA system 106 will be described below with reference to headings that each correspond to one or more blocks shown in FIG. 3. It should be noted that the illustrated embodiment is only one example of an arrangement of components that may be present in the disclosed PMA system 106 and other example arrangements may be possible. For example, certain blocks shown in FIG. 3 may be optional in the disclosed PMA system 106. The functions of multiple blocks shown in FIG. 3 may be combined into a single component in the PMA system 106 without departing from the scope of the present disclosure. Other components not shown in the blocks of FIG. 3 may be part of the PMA system 106 without departing from the scope of the present disclosure.

[0035] Transient Recorder Equipment - Hardware / Firmware / Software

[0036] As discussed above, the transient recorder equipment 112 may include hardware, firmware, and / or software. The transient recorder equipment 112 may be located at the installation near the electrical power system being monitored. The transient recorder equipment 112 includes channels 300 through which signals from various sensors may be input to the transient recorder equipment 112. As illustrated, the transient recorder equipment 112 may include several components including, but not limited to, a high sampling rate input processing component 302, an internal variable computations component 304, a pattern analysis pre-processing / processing component 306, recorder trigger logic 308, an alarm / alert processing component 310, a data recorder 312, a high speed data recorder 314, data buffers / processing component 316, and a communications processing component 318.

[0037] Voltage Sensors and Current Sensors

[0038] The voltage sensors 118 (e.g., 118A and 118D of FIG. 2) are incorporated into the electrical power system (102 of FIG. 1) and are each configured to sense a voltage in the power system and to communicate a signal representative of the sensed voltage to the transient recorder equipment 112. The voltage sensors 118 may include traditional transformers as well as other types of sensors to be selected according to the characteristics of the electrical power system. The voltage sensors 118 are configured within the electrical power system to detect three phase voltage within the power system. The data output from the voltage sensors may be analog or digital.

[0039] The current sensors 118 (e.g., 118B and 118C of FIG. 2) are incorporated into the electrical power system as well and are each configured to sense a current in the power system and to communicate a signal representative of the sensed current to the transient recorder equipment112. The current sensors 118 may include traditional transformers as well as other types of sensors to be selected according to the characteristics of the electrical power system. The current sensors 118 are configured within the electrical power system to detect three phase current within the power system. The data output from the current sensors may be analog or digital.

[0040] The following description of analog channels (e.g., channels 300) within the transient recorder equipment 112 applies to embodiments in which the voltage / current sensors 118 output analog sensor data. The sampling frequency of analog channels in the transient recorder equipment 112 may be configurable with a minimum rate of 30 kHz. The measurements of the analog channels may have an accuracy of within 0.5% or better. The amplitude resolution of the analog channels may be at a minimum in line with the performance of a 16-bit analog-to-digital converter. Higher sampling rates, accuracy, and amplitude resolution may be used by the transient recorder equipment 112 to provide data for comparative analysis where necessary to discern system inherent switching frequency from abnormal conditions in the current / voltage waveforms. The transient recorder equipment 112 may be capable of using several types of current and voltage sensors 118 selected to provide an accurate representation of the signals with minimal effect from saturation or resonance.

[0041] System Status Information

[0042] The transient recorder equipment 112 may also receive one or more system status signals 218 carrying system status information. The system status information can be any equipment or electrical system condition used by the transient recorder equipment 112. The system status information may be provided by one or more additional sensors (e.g., 118 of FIG. 1) located in the electrical power system for detecting various aspects of the status of the power system. The system status information may represent any information regarding what is happening in the electrical system outside of the current and voltage sensor measurements. For example, if a breaker is opened somewhere in the power system, this change may affect the power source or load characteristics as seen by an ASD. It is desirable to collect this system status information, because the status information could be used to help explain away unexpected changes in the electrical patterns.

[0043] Clock Sync Signal

[0044] The transient recorder equipment 112 may include an internal clock (not shown) to time tag all signals and each event record determined by the PMA system 106. This internal clock will be externally synchronized to the clock sync signal 216. External time synchronization methods may include: global positioning system (GPS) synchronization with an internal receiver; GPS synchronization with an external central clock; or synchronization to personal computer (PC) time.

[0045] High Sampling Rate Input Processing

[0046] The high sampling rate input processing component 302 provides the initial processing (e.g., from analog to digital) of sensor signals 118, system status signals 218, and the clock sync signal 216 before sending data to the data recorder 312, high speed data recorder 314, and / or recorder trigger logic 308. The high sampling rate input processing component 302 may receive signals from the voltage sensors 118 and current sensors 118, system status signals 218, and clock sync signal 216 and output digital data to the internal variable computations component 304, the alarm / alert processing component 310, the recorder trigger logic component 308, the data recorder 312, the high speed data recorder 314, and the pattern analysis pre-processing / processing component 306.

[0047] Internal Variable Computations

[0048] The internal variable computations component 304 may perform calculations on the sensor data and other input data received at the high sampling rate input processing component 302. These are calculations that will be performed in the transient recorder equipment 112, in real time or near-real time. The PMA system 106 may perform other calculations as well in the control system 114. However, these other calculations performed by the control system 114 would happen after a time delay, upon triggering from the transient recorder equipment 112, as part of a schedule, or on demand from an operator or system.

[0049] The internal variables may be any variables that can be extracted from waveforms of the current and sensor measurements. The internal variables calculated in the internal variable computation component 304 may include, for example, impedance. In certain embodiments, other values may be calculated in the internal variable computation component 304 as well, such as active power, reactive power, and frequency, among others. In some embodiments, the internal variable computations may include calculating the harmonics of one or more of the sensor signals or calculated values. In summary, the internal variable computations may include impedance in any form, harmonics on any values, rate of change of any variable, and any other variables so deemed necessary for functionality of the PMA system 106.

[0050] The internal variable computations component 304 may output data to the alarm / alert processing component 310, the recorder trigger logic component 308, the data recorder 312, the high speed data recorder 314, and the pattern analysis pre-processing / processing component 306.

[0051] Pattern Analysis Pre-processing / Processing

[0052] In the PMA system 106 certain functions, such as pattern analysis, may be split between the transient recorder equipment 112 and external system software 301 (e.g., in the control system 114). Some parts of the pattern of a variable (e.g., impedance, angle, etc.) may be pre-processedin the transient recorder equipment 112 to reduce the size of the data being communicated to the external software 301 for further processing and analysis. The pattern analysis pre- processing / processing component 306 may receive inputs from the high sampling rate input processing component 302 and / or the internal variable computations component 304, and output processed or pre-processed data patterns to the data buffers / processing component 316.

[0053] Recorder Trigger Logic

[0054] The recorder trigger logic 308 may be used to cause the transient recorder equipment 112 to gather a record (e.g., a “snapshot”) of data received from the various sensors 118 and the calculated variables. This snapshot of data is collected by the data recorder 312 and / or the high speed data recorder 314. Each snapshot may include data corresponding to as few as a fraction of a cycle of the electrical power data and as many cycles as necessary to gather sufficient information (e.g., ten, fifty, or one hundred cycles and so on). Upon triggering by the recorder trigger logic 308, the snapshots are collected and communicated from the transient recorder equipment 112 to the external system software 301 for further processing. As described further below, the recorder trigger logic 308 may trigger the collection and communication of data records based on any one of several possible conditions: when an issue is detected in the raw current / voltage data, when the system status changes, when something unusual happens in the internally calculated variables, and / or at regular intervals.

[0055] Arecording may be triggered based on measured signals (i.e., raw current / voltage data). For example, the recording may be triggered in response to a magnitude of the current or the voltage falling below or rising above a pre-set threshold. As another example, the recording may be triggered in response to the rate of change of the current or the voltage falling below or rising above a pre-set threshold. As another example, the recording may be triggered in response to detection of some other notable event from the raw current / voltage signals, temperature signals, active power, reactive power, motion, vibration, or other sensor signals.

[0056] A recording may be triggered based on external signals (i.e., system status changes). The system status information triggers (based on system status signal 218) may be provided via communications such as Generic Object Oriented Substation Event (GOOSE) or via hardwired contacts.

[0057] A recording may be triggered based on internal signals (i.e., internally calculated variables from the internal variable computations component 304). The internal signal refers to any calculated variable, relation between calculated variables, relation between measured values, or relation between measured values and calculated variables.

[0058] A recording may be triggered based on set timing triggering (i.e., regular intervals). This refers to the triggers happening on a set timing such as a time of day, a number of times per day, every second, minute, or hour, or another timed interval. The time interval could be configurable based on the application.

[0059] The recorder trigger logic 308 may output signals to the data recorder 312, the high speed data recorder 314, and the alarm / alert processing component 310.

[0060] Alarm / Alert Processing

[0061] The alarm / alert processing component 310 may output, based on information received from the high sampling rate input processing component 302, the internal variable computations component 304, or the recorder trigger logic 308, an alarm or alert. The alarm or alert may be output to a user interface (e.g., part of the authorized system(s) 117) for notifying a user of the detected event or triggered data recordation. In some embodiments, the alarm / alert processing component 310 may embed details of the event as part of the alarm / alert. For example, in a subsea operation, if the sensor data indicates a fault in the cabling, then the alarm / alert processing component 310 may embed fault type and location, as determined by internal calculations based on the impedance, as part of the alarm / alert.

[0062] The system software 301 may also include an alarm / alert processing component 322 that functions similarly to the alarm / alert processing component 310 of the transient recording equipment 112. This alarm / alert processing component 322 may receive data from data buffers / processing component 324 and a pattern recognition and analysis component 326 in the system software 301.

[0063] Data Recorder and High Speed Data Recorder

[0064] The data recorder 312 and high speed data recorder 314 may each provide recordings of sensor signals (from 302) and calculated internal variables (from 304) when triggered by the trigger logic component 308. Using the data recorder 312 and / or the high speed data recorder 314, the PMA system 106 may record signals (e.g., event information) in digital form including protection equipment status, switching device status, and other such signals used for analysis of simultaneous signals. The signals may be via contacts (such as normally open and normally closed) and via communications such as IEC61850 / GOOSE. The PMA system 106 may record all signals simultaneously, stamped to the same time reference. The PMA system 106 may handle system frequencies from 0 Hz to multiple above the fundamental frequencies (e.g., 50 Hz, 60 Hz, etc.), with different frequency ranges being managed by the data recorder and the high speed data recorder. For example, the PMA system 106 may handle system frequencies from 0 Hz to 2 MHz, from 0 Hz to 150 kHz, or from 0 Hz to 6 kHz.

[0065] Data Buffers / Processing

[0066] The data buffers / processing component 316 may buffer recorded snapshot data to be sent from the transient recorder equipment 112 to the system software 301. The data buffers / processing component 316 may receive data from the data recorder 312, the high speed data recorder 314, and the pattern analysis pre-processing / processing component 306. A similar data buffers / processing component 324 may be present in the system software 301. That data buffers / processing component 324 may output data to the logic / equation / sequence builder and analyzer 328, the alarm / alert processing component 322, and the pattern recognition and analysis component 326 in the system software 301.

[0067] System Software

[0068] As discussed above, the control system (114 of FIG. 1) may include the system software 301. The control system having the system software 301 may be located remote from the installation and thus remote from the transient recorder equipment 112. The system software 301 is communicatively coupled to the transient recorder equipment 112 via their respective communications processing components 318 and 330. As illustrated, the system software 301 may include several components including, but not limited to, a pattern recognition and analysis component 326, a machine learning component 332, logic / equation / sequence builder and analyzer 328, a troubleshooting assistant 334, an alarm / alert processing component 322, data buffers / processing component 324, and the communications processing component 330. Certain of these components such as, for example, the machine learning component 332, troubleshooting assistant 334, and / or logic / equation / sequence builder and analyzer 328 may be optional.

[0069] Pattern Recognition and Analysis

[0070] The pattern recognition and analysis component 326 in the system software 301 may be capable of analyzing and comparing waveform patterns and their calculated variables through the full operating range. The pattern recognition and analysis component 326 may receive the records (i.e., snapshots) of sensor data and / or other calculated variables from the transient recorder equipment 112 and output signals to the alarm / alert processing component 322 to provide alerts when anomalies are found in the patterns of the data. In some embodiments, the pattern recognition and analysis component 326 may work integrally with a machine learning component 332. For example, the pattern recognition and analysis component 326 may send time-based signals of sensor data, calculated variables, and / or other calculated parameters to the machine learning component 332 operating in a learning mode to obtain a “fingerprint” of normal waveform performance characteristics of the data. The system software 301 may include user selectable parameters and ranges to trigger an alarm when the present operating waveform deviates from this“fingerprint” waveform by these settings. In general, the pattern recognition and analysis component 326 may determine whether a record received from the transient recorder equipment 112 represents a correct pattern (one that conforms to the expected fingerprint) or an incorrect pattern (one that deviates from the expected fingerprint). In some embodiments, the pattern recognition and analysis component 326 may also track patterns in the harmonics or other parameters over time and determine if the patterns experience changes that are trending in a given direction over time.

[0071] It should be noted that the pattern analysis available through one or both of the transient recorder equipment 112 (via the pattern analysis pre-processing / processing component 306) and system software 114 (via the pattern recognition and analysis component 326) may provide the following functionality. The pattern analysis may be based on a pattern in the voltage signals, current signals, or a calculation based on the two (e.g., impedance). Other calculations besides impedance may include phase angle(s) between the different current signals or voltage signals, or other electrical characteristics. The pattern analysis may include learning a pulsing pattern of any of these sensors signals and / or calculated parameters for a given point of operation of the electrical power system (such as speed / frequency and load), and then comparing the pulse patterns overtime. Still other calculations may include harmonic decompositions of the various waveforms. The pattern analysis may include monitoring how the harmonics from these decompositions change over time, particularly the later harmonics. By regularly monitoring the harmonics in the sensor signals or other calculations over time, the machine learning component 332 and / or troubleshooting component 334 may learn that changes in a given direction of one or more characteristics can predict an upcoming fault or other failure in the electrical power system.

[0072] Machine Learning

[0073] The machine learning component 332 may be communicatively coupled to or formed integral with the pattern recognition and analysis component 326. The machine learning component 332 may determine a fingerprint against which later records of parameters received from the transient recorder equipment 112 will be compared. The learning parameters used for the machine learning / artificial intelligence (Al) may include the sensor data, calculated variables received from the transient recorder equipment 112, and any comparisons of the sensor data / calculated variables. The waveform and calculated variables comparisons can be programmed by an operator and / or selected autonomously by the Al in the machine learning component 332.

[0074] Logic / Equation / Sequence Builder and Analyzer

[0075] The logic / equation / sequence builder and analyzer 328 may act as a formula editor to make further mathematical calculations within records received from the transient recorderequipment 112. Available functions within the logic / equation / sequence builder 328 may include, among others, harmonic spectrum computations, Fast Fourier Transform (FFT) algorithms, algebraic algorithms, trigonometric algorithms, logarithmic algorithms, derivative algorithms, and integration algorithms. Results of the further calculations may be added to the record as additional signals for pattern analysis by the pattern recognition and analysis component 326.

[0076] Troubleshooting Assistant

[0077] The troubleshooting assistant 334 may be communicatively coupled to or formed integral with the pattern recognition and analysis component 326. The troubleshooting assistant 334 may provide electrical system or equipment troubleshooting such as fault analysis, fault location, type of fault, pattern alerts / alarms, and / or a list of possible causes and actions based on the analysis provided by the pattern recognition and analysis component 326.

[0078] Other Equipment or System Data

[0079] Other equipment or system data 336 (e.g., collected by sensors other than the voltage and current sensors 118) may be received at specific channels in the PMA system 116. The other equipment or system data 336 may include mechanical or environmental information such as vibration, temperature, pressure, level, motion data, or other information that may be used in the pattern analyses (in components 306 and 326) of the PMA system 106.

[0080] Authorized Systems

[0081] The authorized systems 117 were described at length above with reference to FIG. 1.

[0082] Other Transient Recorder Equipment

[0083] In some embodiments, the PMA system 106 may include system software 301 that can read and process data from multiple transient recorders (having the same or similar structure / function of transient recorder equipment 112). For example, as shown in FIG. 3, the PMA system 106 may include other transient recorder equipment 338 used to record, monitor, and process sensor signals received from another electrical power system. Each drive may have its own transient recorder equipment (e.g., 112, 338) communicatively coupled to the same control system 114 with the system software 301.

[0084] Communications Processing

[0085] The communications processing components 318 and 330 provide communication interfaces for sending communications between one or more pieces of transient recorder equipment 112, 338 and the system software 301, between the transient recorder equipment 112, 338 and the authorized systems 117, and / or between the system software 301 and the authorized systems 117. In addition, the PMA system 106 may be capable of integration via communications processingcomponents 318, 330 to other electrical protection and control devices (e.g., switchgear 202 of FIG. 2) for exchange of data needed for analysis.

[0086] In the PMA system 106, data import and export facilities may use Common format for Transient Data Exchange for power systems (COMTRADE) format in accordance with IEC 60255- 24, allowing comparison and analysis on a common platform. The PMA system 106 may facilitate additional data formats including Comma Separated Values (CSV) format and IEEE Std 1159.3 Power Quality Data Interchange Format (PQDIF). Other communication formats may be used as well.

[0087] FIG. 4 is a process flow diagram illustrating a method 400 for monitoring an electrical power system (including events in the electrical power system), in accordance with an embodiment of the present disclosure. It should be noted that the method 400 shown in FIG. 4 is merely an example and other embodiments may include additional steps not shown, have one or more illustrated steps removed, or have certain illustrated steps performed in different orders than shown, without departing from the scope of the present disclosure. Certain steps may be performed by a PMA system (e.g., by transient recorder equipment and / or a control system communicatively coupled to the transient recorder equipment).

[0088] At block 402, the method 400 includes delivering electrical power from an electrical power system to a device for powering the device. The device may be a subsea device, as shown and discussed with respect to FIGS. 1 and 2. At block 404, the method 400 includes receiving, e.g., at transient recorder equipment, current measurements and voltage measurements from sensors located in the electrical power system. At block 406, the method 400 may include calculating, e.g., via the transient recorder equipment, one or more variables based on the received current measurements and / or voltage measurements. The variable(s) may be calculated in real time or near-real time. The one or more calculated variables may include an impedance, a rate of change of current, a rate of change of voltage, a rate of change of impedance, a harmonic decomposition of current, a harmonic decomposition of voltage, a harmonic decomposition of impedance, or any combination thereof. The calculated variable(s) may each be time-synced to the current and voltage measurements. At block 408, the method 400 may include receiving, e.g., at the transient recorder equipment, signals regarding a status of the electrical power system and / or other sensor measurements.

[0089] At block 410, the method 400 includes triggering, e.g., via the transient recorder equipment, a digital data recording of at least the current measurements and the voltage measurements taken over a period of time. The digital data recording may also include the calculated variables from block 406, the received system status signals from block 408, and / orother data. The recording may be performed by one or both of: a first data recorder operating in a first frequency range and a second data recorder operating in a second frequency range greater than the first frequency range. In certain embodiments, the digital data recording may be triggered based on the current measurements and / or the voltage measurements (block 404). In certain embodiments, the digital data recording may be triggered based on one or more calculated variables (block 406). In certain embodiments, the digital data recording may be triggered based on a signal indicating system status of the electrical power system received at the transient recorder equipment (block 408). In certain embodiments, the digital data recording may be triggered based on a preset trigger timing. At block 412, the method 400 includes communicating the digital data recording to the control system communicatively coupled to the transient recorder equipment. Although not specifically shown in FIG. 4, it should be noted that the transient recorder equipment may also output an alarm or alert based on the current measurements, based on the voltage measurements, and / or upon triggering the digital recording. Blocks 404-412 may be repeated throughout operation of the electrical power system as it delivers operating power to the device.

[0090] At block 414, the method 400 may include performing computations on the data from the digital data recording via a logic / equation / sequence builder and analyzer in the control system, and inputting results of the computations on the data into the digital data recording. At block 416, the method 400 may include generating an expected time-based pattern of current and voltage (and / or calculated variables, system status values, etc.) via a machine learning component in the control system. Inputs to the machine learning component may include prior digital data recordings that were received at the control system. At block 418, the method 400 includes comparing, via a pattern recognition / analysis component of the control system, the digital data recording to an expected time-based pattern of at least current and voltage, and possibly also calculated variables (such as those calculated at block 406), system status information (e.g., such as those received at block 408), or other parameters. The expected time-based pattern may be generated by the machine learning component in block 416, or may be programmed into the control system by a user. At block 420, the method 400 includes outputting an alarm or alert based on the digital data recording deviating from the expected time-based pattern (YES to block 418). If there is no deviation or less than a threshold deviation at block 418 (NO), the process may return to evaluating the next digital data recording that is communicated to the control system. The method 400 may include analyzing an output from the pattern recognition and analysis component to monitor, analyze, and / or troubleshoot the electrical power system. For example, at block 422, the method 400 may include analyzing an output from the pattern recognition and analysis component to troubleshoot the electrical power system via a troubleshooting assistant.

[0091] In general, the disclosed PMA system may exhibit the following functionality. The system may provide continuous recordings of selected analog values (e.g., current and voltage). The system may provide real-time monitoring of the sensor signals and / or calculations based on the sensor signals. The system may apply mathematical functions to recorded and derived analog values. The system may provide digital fault recording. The system may provide impedancebased fault location using dynamic base impedance. The system may provide disturbance recording, event recording, and sequence of events recording. The system may provide power quality monitoring. The system may include waveform pattern comparison and analysis. The system may include time varying harmonic spectrum comparison and analysis, time varying root mean square (RMS) values comparison and analysis, and / or time varying symmetrical component analysis.

[0092] Some example illustrative embodiments will now be listed:

[0093] Embodiment 1 : A system, including: an electrical power system configured to deliver electrical power to a device for powering the device; at least one current sensor and at least one voltage sensor, each sensor located in the electrical power system; transient recorder equipment communicatively coupled to the at least one current sensor and the at least one voltage sensor; and a control system communicatively coupled to the transient recorder equipment, wherein the transient recorder equipment includes multiple components configured to: receive current measurements from the at least one current sensor and voltage measurements from the at least one voltage sensor; trigger a digital data recording of the current measurements and the voltage measurements taken over a period of time; and communicate the digital data recording to the control system, and wherein the control system is configured to: compare the digital data recording to an expected time-based pattern of current and voltage; and output an alarm or alert based on the digital data recording deviating from the expected time-based pattern.

[0094] Embodiment 2: The system of Embodiment 1, wherein: the transient recorder equipment is configured to calculate one or more internal variables based on the received current measurements and / or voltage measurements, the triggered digital data recording is of the current measurements, the voltage measurements, and the calculated variables taken over the period of time, and the digital data recording is compared to an expected time-based pattern of current, voltage, and variables.

[0095] Embodiment 3: The system of Embodiment 1, wherein the control system is remote from and communicatively coupled to the transient recorder equipment.

[0096] Embodiment 4: The system of Embodiment 1, wherein the control system and the transient recorder equipment are integrated together at one location.

[0097] Embodiment 5 : The system of Embodiment 1 , wherein the transient recorder equipment includes hardware, firmware, and / or software, and the control system includes software.

[0098] Although embodiments described herein are made with reference to example embodiments, it should be appreciated by those skilled in the art that various modifications are well within the scope and spirit of this disclosure. Those skilled in the art will appreciate that the example embodiments described herein are not limited to any specifically discussed application and that the embodiments described herein are illustrative and not restrictive. From the description of the example embodiments, equivalents of the elements shown therein will suggest themselves to those skilled in the art, and ways of constructing other embodiments using the present disclosure will suggest themselves to practitioners of the art. Therefore, the scope of the example embodiments is not limited herein.

Claims

CLAIMSWhat is claimed is:

1. A method, compri sing : delivering electrical power from an electrical power system to a device for powering the device; receiving, at transient recorder equipment, current measurements and voltage measurements from sensors located in the electrical power system; triggering, via the transient recorder equipment, a digital data recording of the current measurements and the voltage measurements taken over a period of time; communicating the digital data recording to a control system communicatively coupled to the transient recorder equipment; comparing, via a pattern recognition / analysis component of the control system, the digital data recording to an expected time-based pattern of current and voltage; and outputting an alarm or alert based on the digital data recording deviating from the expected time-based pattern.

2. The method of claim 1, further comprising: calculating, via the transient recorder equipment, one or more variables based on the received current measurements and / or voltage measurements.

3. The method of claim 2, wherein: the triggered digital data recording is of the current measurements, the voltage measurements, and the calculated variables taken over the period of time, and the digital data recording is compared to an expected time-based pattern of current, voltage, and variables.

4. The method of claim 2, wherein the digital data recording is triggered based on the calculated variables.

5. The method of claim 2, further comprising time syncing the current measurements and the voltage measurements to the calculated variables.

6. The method of claim 2, wherein the one or more calculated variables include an impedance, a rate of change of current, a rate of change of voltage, a rate of change of impedance, a harmonic decomposition of current, a harmonic decomposition of voltage, a harmonic decomposition of impedance, or any combination thereof.

7. The method of claim 1, wherein the triggered digital data recording is of the current measurements, the voltage measurements, and one or both of: variables calculated internally based on the current measurements and / or the voltage measurements; received signals indicating a system status, a temperature, acceleration, motion, vibration, active power, and / or reactive power of the electrical power system.

8. The method of claim 1, further comprising obtaining the digital data recording using one or both of: a first data recorder operating in a first frequency range; and a second data recorder operating in a second frequency range greater than the first frequency range.

9. The method of claim 1, wherein the digital data recording is triggered based on the current measurements and / or the voltage measurements.

10. The method of claim 1, wherein the digital data recording is triggered based on a signal indicating system status, temperature, acceleration, motion, vibration, active power, and / or reactive power of the electrical power system received at the transient recorder equipment.

11. The method of claim 1, wherein the digital data recording is triggered based on a preset trigger timing.

12. The method of claim 1, further comprising outputting an alarm or alert from the transient recorder equipment based on the current measurements, based on the voltage measurements, and / or upon triggering the digital recording.

13. The method of claim 1, further comprising generating the expected time-based pattern of current and voltage via a machine learning component in the control system.

14. The method of claim 1, further comprising: performing computations on data from the digital data recording via a logic / equation / sequence builder and analyzer in the control system; and inputting results of the computations on the data into the digital data recording for analysis by the pattern recognition / analysis component.

15. The method of claim 1, further comprising analyzing an output from the pattern recognition and analysis component to monitor, analyze, and / or troubleshoot the electrical power system.

16. The method of claim 1, wherein the electrical power system is a subsea power drive system, subsea power transmission system, or subsea power distribution system.

17. The method of claim 1, wherein the electrical power is delivered from the electrical power system to the device via an insulated cable having a length greater than 5 km.

18. A system, comprising: an electrical power system configured to deliver electrical power to a device for powering the device; at least one current sensor and at least one voltage sensor, each sensor located in the electrical power system; transient recorder equipment communicatively coupled to the at least one current sensor and the at least one voltage sensor; and a control system communicatively coupled to the transient recorder equipment, wherein the transient recorder equipment comprises multiple components configured to: receive current measurements from the at least one current sensor and voltage measurements from the at least one voltage sensor; trigger a digital data recording of the current measurements and the voltage measurements taken over a period of time; and communicate the digital data recording to the control system, andwherein the control system is configured to: compare the digital data recording to an expected time-based pattern of current and voltage; and output an alarm or alert based on the digital data recording deviating from the expected time-based pattern.

19. The system of claim 1, wherein the device being powered is a subsea device operably coupled to the electrical power system via a subsea cable.

20. The system of claim 1, further comprising: a second electrical power system configured to deliver electrical power to a second device for powering the second device; and a second transient recorder equipment communicatively coupled to at least one current sensor and at least one voltage sensor located in the second electrical power system, wherein the control system is communicatively coupled to both the transient recorder equipment and the second transient recorder equipment.

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