An open-type integrated current measurement and traveling wave distance measurement sensor for a ring main unit

Abstract

This invention discloses an openable integrated current measurement and traveling wave ranging sensor for ring main units, relating to the field of sensor technology. It includes a housing, a current measurement component, and a traveling wave ranging component; the housing comprises a first main body and a second main body. By coaxially integrating the current measurement component and the traveling wave ranging component into the same housing, high-precision power frequency current measurement and wideband fault transient traveling wave capture are achieved. This solves the problems of single-function sensors and inconsistent electromagnetic coupling caused by separate installations. Simultaneously, it achieves a highly compact structure, addressing the technical problem of limited space in ring main units leading to difficulties in configuring multiple devices. Furthermore, the housing adopts an openable / closed structure design, allowing the current measurement and traveling wave ranging sensor to be directly mounted on the operating busbar without interrupting power or disconnecting the busbar under test, enabling live installation and maintenance.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to an open-type integrated current measurement and traveling wave ranging sensor for ring main units. Background Technology

[0002] With the continuous advancement of intelligent power distribution network construction, ring main units (RNBs), as key node equipment in the distribution network, play a crucial role in ensuring power supply reliability through real-time monitoring of their operating status and rapid fault location. Currently, current measurement and traveling wave ranging functions in RNBs are typically implemented using independently installed sensors. Power frequency interference and high-frequency electromagnetic interference are easily coupled into the signal loop, affecting measurement accuracy and the accuracy of traveling wave front timing calibration. Secondly, due to the limited internal space of RNBs, separate installation is not only difficult during the installation process but also results in overcrowding of the internal space of the RNB after installation. Summary of the Invention

[0003] The purpose of this invention is to provide an open-type integrated current measurement and traveling wave ranging sensor for ring main units to solve the above-mentioned technical problems.

[0004] Specifically, the present invention provides the following technical solution: an openable integrated current measurement and traveling wave ranging sensor for ring main units, comprising a housing, a current measurement component, and a traveling wave ranging component; wherein, the housing comprises a first main body and a second main body; the first main body is rotatably openable and rotatably closed relative to the second main body; the first main body is rotatably closed relative to the second main body to form a circumferentially closed first cavity and a second cavity; the first cavity is sleeved on the outside of the second cavity; the current measurement component and the traveling wave ranging component are disposed in the first cavity; the second cavity is axially through for the busbar under test to pass through; the current measurement component is used to sense the power frequency current signal in the busbar under test to achieve accurate measurement of the power frequency current of the busbar under test; the traveling wave ranging component is used to simultaneously sense the power frequency current signal and the fault transient traveling wave signal in the busbar under test, and after integral filtering and separation, provides a high-precision time-stamp signal for the traveling wave ranging algorithm.

[0005] As a preferred embodiment of the openable integrated current measurement and traveling wave ranging sensor for ring main units described in this invention, wherein: the first body and the second body both include an outer wall plate, an inner wall plate, and a bottom wall plate connected between the outer wall plate and the inner wall plate; wherein, the first cavity is formed between the outer wall plate, the inner wall plate, and the bottom wall plate, and the second cavity is formed by the inner wall plate.

[0006] As a preferred embodiment of the open-type integrated current measurement and traveling wave ranging sensor for ring main units described in this invention, the current measurement component includes an electromagnet core, a secondary winding coil, and a signal conversion module; wherein the electromagnet core includes a movable section and a fixed section; the movable section and the fixed section are respectively embedded in the first body and the second body, and the movable section and the fixed section are connected to form a complete electromagnetic path; the secondary winding coil is wound on the outer surface of the electromagnet core to form an electromagnetic induction area; the signal conversion module is electrically connected to the lead wire of the secondary winding coil.

[0007] As a preferred embodiment of the open-type integrated current measurement and traveling wave ranging sensor for ring main units described in this invention, the signal conversion module includes a current-to-voltage converter and a signal amplification circuit; wherein, the current-to-voltage converter is used to convert the weak current signal output by the induction winding module into a voltage signal; the signal amplification circuit is used to amplify, filter, and standardize the voltage signal obtained by the current-to-voltage converter to output a stable 0V to 5V standard voltage signal; the signal conversion module has a built-in overvoltage protection circuit to prevent secondary side overvoltage from damaging the equipment.

[0008] As a preferred embodiment of the open-type integrated current measurement and traveling wave ranging sensor for ring main units described in this invention, the traveling wave ranging component includes a hollow core frame, a Rogowski coil, and an integral conditioning circuit; wherein the hollow core frame and the electromagnet core are coaxially arranged and jointly housed within the first cavity; the hollow core frame includes a first part and a second part, which are connected and closed; the Rogowski coil is uniformly wound on the outer surface of the hollow core frame; and the integral conditioning circuit is electrically connected to the output terminal of the Rogowski coil.

[0009] As a preferred embodiment of the open-type integrated current measurement and traveling wave ranging sensor for ring main units described in this invention, the integral conditioning circuit includes an active integrator and a bandpass filter; wherein, the active integrator is used to integrate and restore the differential current signal output by the Rogowski coil to obtain the true power frequency current waveform; the bandpass filter is used to separate the power frequency signal and the high-frequency traveling wave signal from the integrated signal, and retain the steep edge characteristics of the high-frequency traveling wave, providing a high-precision time-stamp signal for the traveling wave ranging algorithm.

[0010] As a preferred embodiment of the open-type integrated current measurement and traveling wave ranging sensor for ring main units described in this invention, the output signals of the current measurement component and the traveling wave ranging component are transmitted to the RTU, microprocessor protection device, and traveling wave ranging host of the ring main unit respectively via multi-core shielded twisted pair cable; the multi-core shielded twisted pair cable includes a measurement-level output pair, a traveling wave ranging power frequency output pair, and a traveling wave ranging high frequency output pair; the measurement-level output pair is used to transmit the 0-5V analog voltage signal output by the current measurement component; the traveling wave ranging power frequency output pair is used to transmit the restored power frequency current signal output by the traveling wave ranging component; the traveling wave ranging high frequency output pair is used to transmit the high frequency traveling wave signal output by the traveling wave ranging component.

[0011] As a preferred embodiment of the open-type integrated current measurement and traveling wave ranging sensor for ring main units described in this invention, the outer casing is equipped with terminals for connecting the measurement stage output pairs, the traveling wave ranging power frequency output pairs, the traveling wave ranging high frequency output pairs, and the grounding wire.

[0012] As a preferred embodiment of the openable integrated current measurement and traveling wave ranging sensor for ring main units described in this invention, the space between the outer shell, the current measurement component, and the traveling wave ranging component is filled with insulating material to provide insulation protection and vibration resistance.

[0013] As a preferred embodiment of the open-type integrated current measurement and traveling wave ranging sensor for ring main units described in this invention, it further includes a shielding component for preventing external electromagnetic interference and ensuring stable signal transmission. The shielding component includes a magnetic circuit shielding layer, a housing shielding layer, and a twisted-pair shielding layer. The magnetic circuit shielding layer includes a permalloy strip covering the outside of the electromagnet core and the secondary winding coil. The housing shielding layer includes a conductive copper mesh layer covering the inner surface of the outer wall panel. The first main body and the second main body are electrically connected to form a complete annular shielding cavity. The twisted-pair shielding layer includes aluminum foil covering the outside of the measurement stage output line pair, the traveling wave ranging power frequency output line pair, and the traveling wave ranging high frequency output line pair.

[0014] The beneficial effects of this invention are as follows: By coaxially integrating the current measurement component and the traveling wave ranging component into the same housing, high-precision power frequency current measurement and wide-band fault transient traveling wave capture are achieved, solving the problems of single sensor function and inconsistent electromagnetic coupling caused by separate installation. At the same time, it achieves a highly compact structure, solving the technical problem of difficulty in configuring multiple devices due to the limited space in the current ring main unit. Secondly, the housing adopts an openable and closable structure design, which allows the current measurement and traveling wave ranging sensors to be directly installed on the bus under test without interrupting power or disconnecting the bus under test, enabling live installation and maintenance. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the current measurement and traveling wave ranging sensor according to one embodiment of the present invention; Figure 2 This is a schematic diagram of the assembly of the current measuring component and the housing in one embodiment of the present invention; Figure 3 This is a schematic diagram of the assembly of the traveling wave ranging component and the outer shell in one embodiment of the present invention; Figure 4 This is a schematic diagram of the outer shell structure according to one embodiment of the present invention; Figure 5 This is a side sectional view of the outer casing according to an embodiment of the present invention; Figure 6 This is a side view of the outer casing according to an embodiment of the present invention.

[0017] In the diagram: 1. Outer shell; 11. First main body; 12. Second main body; 13. First cavity; 14. Second cavity; 15. Outer wall panel; 16. Inner wall panel; 17. Bottom wall panel; 18. Cable clip; 2. Current measuring assembly; 21. Electromagnetic core; 211. Moving section; 212. Fixed section; 22. Secondary winding coil; 23. Low-temperature drift non-inductive metal film resistor; 3. Traveling wave ranging assembly; 31. Hollow core frame; 311. First part; 312. Second part; 32. Rogowski coil; 4. Docking guide mechanism; 41. Positioning protrusion; 42. Guide groove; 5. Circuit board; 6. Terminal block; 7. Insulating material; 8. Locking mechanism; 81. Steel strip; 82. Locking buckle; 83. Locking tongue; 9. Multi-core shielded twisted pair cable. Detailed Implementation

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0019] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0020] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0021] Furthermore, the present invention will be described in detail with reference to the schematic diagrams. When describing the embodiments of the present invention in detail, for ease of explanation, the cross-sectional views of the device structure will be partially enlarged without adhering to the general scale. Moreover, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention.

[0022] Reference Figures 1-6 In this embodiment, an open-type integrated current measurement and traveling wave ranging sensor for ring main units is proposed. The purpose is to integrate the traditionally independent power frequency current measurement function and fault traveling wave ranging function into a single open-type sensor. That is, by coaxially arranging the current measurement component 2 based on the low power coil (LPCT) principle and the traveling wave ranging component 3 based on the Rogowski coil 32 principle in the same open-type housing 1, high-precision power frequency current measurement and wide-bandwidth fault transient traveling wave capture are realized simultaneously. This solves the technical problems of the current sensors having single functions and the difficulty of configuring multiple devices due to the small space of the ring main unit. Moreover, the current measurement and traveling wave ranging sensor can be directly installed on the bus under test without interrupting power or disconnecting the bus under test, realizing live installation and maintenance.

[0023] Reference Figures 1-6 In this embodiment, the current measurement and traveling wave ranging sensor includes a housing 1, a current measurement component 2, and a traveling wave ranging component 3.

[0024] Furthermore, refer to Figure 2 In this embodiment, the outer shell 1 includes a first body 11 and a second body 12. The first body 11 is rotatably openable and rotatably closed relative to the second body 12.

[0025] Specifically, the first body 11 rotates and closes relative to the second body 12 to form a circumferentially closed first cavity 13 and second cavity 14. The first cavity 13 and second cavity 14 are arranged in a nested configuration, as shown below. Figure 3 and Figure 5 The first cavity 13 is sleeved on the outside of the second cavity 14. In this embodiment, the first body 11 can rotate more than 90° relative to the second body 12 to open the second cavity 14, so as to achieve a seamless connection with the busbar under test. That is, the current measurement and traveling wave ranging sensor can be mounted on the busbar under test without cutting off the busbar under test.

[0026] Specifically, the first cavity 13 is equipped with the current measuring component 2 and the traveling wave ranging component 3. The second cavity 14 extends axially to allow the busbar to be measured to pass through.

[0027] Specifically, refer to Figure 5 The first body 11 and the second body 12 each include an outer wall panel 15, an inner wall panel 16, and a bottom wall panel 17 connected between the outer wall panel 15 and the inner wall panel 16. The first cavity 13 is formed between the outer wall panel 15, the inner wall panel 16, and the bottom wall panel 17, and the second cavity 14 is formed by the inner wall panel 16.

[0028] Specifically, the inner wall plate 16 is provided with a cable clip 18 on one side corresponding to the second cavity 14 for fixing the busbar to be tested.

[0029] Specifically, the outer shell 1 is injection molded from ABS flame-retardant plastic, which has excellent mechanical strength, high flame retardancy and high insulation.

[0030] Furthermore, refer to Figure 2 In this embodiment, the current measurement component 2 operates based on the low-power coil (LPCT) principle and is used to sense the power frequency current signal in the bus under test in order to achieve accurate measurement of the power frequency current of the bus under test. It includes an electromagnet core 21, a secondary winding coil 22, and a signal conversion module.

[0031] Specifically, the electromagnet core 21 has a segmented structure, including a movable segment 211 and a fixed segment 212. The movable segment 211 and the fixed segment 212 are respectively embedded in the first body 11 and the second body 12.

[0032] Specifically, the movable segment 211 and the fixed segment 212 are docked to form a complete electromagnetic path. The docking surfaces of the movable segment 211 and the fixed segment 212 are precision ground to a surface roughness Ra≤0.8μm and are equipped with a docking guide mechanism 4 to ensure that the closing gap after docking is ≤0.1mm, effectively reducing the magnetic resistance of the magnetic circuit.

[0033] Specifically, the docking guide mechanism 4 includes a positioning protrusion 41 disposed on the docking surface of the movable segment 211 and / or the fixed segment 212, and a guide groove 42 disposed on the docking surface of the fixed segment 212 and / or the movable segment 211.

[0034] Specifically, the electromagnet core 21 is made of iron-based amorphous alloy material, which has both low hysteresis loss (specific loss ≤ 0.2 W / kg @ 50 Hz, 1.0 T) and high saturation magnetic flux density (Bs ≥ 1.56 T) characteristics, ensuring that it can still work stably under transient short-circuit current and does not experience magnetic saturation.

[0035] Specifically, the secondary winding coil 22 is wound on the outer surface of the electromagnet core 21 to form an electromagnetic induction zone, and outputs a current signal to monitor and acquire the power frequency current signal of the bus under test.

[0036] Specifically, the secondary winding coil 22 is wound with high conductivity copper wire, preferably with high conductivity enameled copper wire with a diameter of 0.15mm (conductivity ≥100% IACS). It is precisely wound using automated winding equipment, and the number of coil turns and winding tension are strictly controlled to ensure the resistance consistency of the secondary winding coil 22 (deviation ≤±1%).

[0037] Specifically, the number of turns of the secondary winding coil 22 is configured according to the rated current ratio requirement. In this embodiment, the number of turns of the phase sequence winding is 1200 turns and the number of turns of the zero sequence winding is 200 turns.

[0038] Specifically, a low-temperature drift non-inductive metal film resistor 23 is connected in parallel across the two ends of the secondary winding coil 22. The low-temperature drift non-inductive metal film resistor 23 has a temperature drift coefficient ≤5ppm / ℃ and a resistance accuracy of ±0.1%, ensuring stable output signal and unchanged error range over a wide temperature range of -40℃ to +70℃.

[0039] Specifically, the signal conversion module is electrically connected to the lead wire of the secondary winding coil 22, and includes a current-to-voltage converter and a signal amplification circuit.

[0040] Specifically, the current-to-voltage converter is used to convert the weak current signal (typically in the mA range) output by the induction winding module into a voltage signal. The signal amplification circuit is used to amplify, filter, and standardize the voltage signal obtained by the current-to-voltage converter to output a stable 0V to 5V standard voltage signal, which can then be directly adapted to secondary equipment such as ring main unit (RTU) and microprocessor-based protection devices.

[0041] Specifically, the signal conversion module has a built-in overvoltage protection circuit to prevent secondary-side overvoltage from damaging the equipment.

[0042] Furthermore, refer to Figure 3 In this embodiment, the traveling wave ranging component 3 operates based on the principle of Rogowski coil 32. It is used to simultaneously sense the power frequency current signal and the fault transient traveling wave signal in the bus under test. After being separated by integral filtering, it provides a high-precision time-stamp signal for the traveling wave ranging algorithm, thereby realizing the accurate location of the fault point of the distribution network line. It includes a hollow core frame 31, Rogowski coil 32 and integral conditioning circuit.

[0043] Specifically, the hollow core frame 31 and the electromagnet core 21 are coaxially arranged and jointly housed within the first cavity 13, ensuring that the traveling wave ranging component 3 and the current measuring component 2 maintain consistent electromagnetic coupling with the busbar under test. Similarly, the hollow core frame 31 has a segmented structure, including a first part 311 and a second part 312, which are connected and closed.

[0044] Specifically, the Rogowski coil 32 is uniformly wound on the outer surface of the hollow core frame 31, and its frequency response range covers high-frequency signals from power frequency (50Hz) to MHz level, which can accurately capture the fault transient traveling wave signal of the circuit under test and simultaneously sense the power frequency current signal.

[0045] Specifically, the integral conditioning circuit is electrically connected to the output of the Rogowski coil 32 and includes an active integrator and a bandpass filter. The active integrator is constructed using a high-precision operational amplifier, such as the AD8429 amplifier, to integrate and restore the differential current signal output from the Rogowski coil 32, obtaining the true power frequency current waveform. The bandpass filter employs a multi-stage active filter structure to separate the power frequency signal (passband: 45Hz-55Hz) and the high-frequency traveling wave signal (passband: 10kHz-1MHz) from the integrated signal, while preserving the steep edge characteristics of the high-frequency traveling wave, providing a high-precision time-stamp signal for the traveling wave ranging algorithm.

[0046] Furthermore, refer to Figure 5 In this embodiment, the signal conversion module and the integral conditioning circuit are integrated on the circuit board 5, which is disposed inside the first cavity 13.

[0047] Furthermore, refer to Figure 4 In this embodiment, the output signals of the current measurement component 2 and the traveling wave ranging component 3 are transmitted to the RTU, microcomputer protection device and traveling wave ranging host of the ring network cabinet respectively through the multi-core shielded twisted pair cable 9.

[0048] Specifically, the multi-core shielded twisted pair cable 9 includes a measurement-level output pair, a traveling wave ranging power frequency output pair, and a traveling wave ranging high frequency output pair. The measurement-level output pair is used to transmit the 0-5V analog voltage signal output by the current measurement component 2; the traveling wave ranging power frequency output pair is used to transmit the restored power frequency current signal output by the traveling wave ranging component 3; and the traveling wave ranging high frequency output pair is used to transmit the high-frequency traveling wave signal output by the traveling wave ranging component 3.

[0049] Specifically, the outer casing 1 is equipped with terminals 6 for connecting the measurement stage output pairs, the traveling wave ranging power frequency output pairs, the traveling wave ranging high frequency output pairs, and the grounding wire.

[0050] Furthermore, refer to Figure 1 In this embodiment, the first cavity 13 is filled with insulating material 7 to provide insulation protection (power frequency withstand voltage ≥42kV / min) and vibration protection.

[0051] Specifically, the insulating material 7 is filled between the outer casing 1 and the current measuring component 2 and the traveling wave ranging component 3 using a vacuum potting process. The insulating material 7 is made of epoxy resin, preferably bisphenol A type epoxy resin, with a vacuum degree ≤100Pa and a curing temperature of 80℃ / 4h + 120℃ / 2h.

[0052] Furthermore, refer to Figure 4 In this embodiment, the first body 11 is connected to the second body 12 through a locking mechanism 8.

[0053] Specifically, the locking mechanism 8 includes a steel band 81, a latch 82, and a locking tongue 83. The outer surface of the outer wall panel 15 is provided with a groove, into which the steel band 81 is embedded. The latch 82 and the locking tongue 83 are respectively located at the two movable ends of the steel band 81, and the latch 82 and the locking tongue 83 can lock together.

[0054] Furthermore, in this embodiment, the current measurement and traveling wave ranging sensor also includes a shielding component to prevent external electromagnetic interference and ensure stable signal transmission, including a magnetic circuit shielding layer, a housing shielding layer, and a twisted pair shielding layer.

[0055] Specifically, the magnetic circuit shielding layer is made of permalloy strip covering the outside of the electromagnet core 21 and the secondary winding coil 22; the shell shielding layer includes a conductive copper mesh layer covering the inner surface of the outer wall plate 15, and the first main body 11 and the second main body 12 are electrically connected to form a complete annular shielding cavity; the twisted pair shielding layer is made of aluminum foil covering the outside of the measurement stage output pair, the traveling wave ranging power frequency output pair and the traveling wave ranging high frequency output pair.

[0056] In summary, the current measurement and traveling wave ranging sensor described in this embodiment, through the outer shell 1 including the first body 11 and the second body 12, enables the current measurement and traveling wave ranging sensor to be directly mounted on the bus under test without interrupting power or disconnecting the bus under test, thus achieving live installation and maintenance.

[0057] Secondly, by setting up a current measurement component 2, including an electromagnet core 21, a secondary winding coil 22 and a signal conversion module, which works based on the low-power coil principle, it senses the power frequency current signal in the busbar under test and has a measurement accuracy of 0.5 class, so as to achieve accurate measurement of the power frequency current of the busbar under test. The electromagnet core 21 has a segmented structure. A docking guide mechanism 4 ensures precise docking of the segmented electromagnet core 21, guaranteeing a closed gap within 0.1mm, thereby effectively reducing magnetic circuit resistance. The electromagnet core 21 is made of iron-based amorphous alloy material, possessing both low hysteresis loss and high saturation magnetic flux density, ensuring stable operation without magnetic saturation under transient short-circuit current. A low-temperature drift non-inductive metal film resistor 23 is connected in parallel across the secondary winding coil 22, ensuring stable output signal over a wide temperature range from -40°C to 70°C. The signal conversion module includes a current-to-voltage converter, a signal amplification circuit, and an overvoltage protection circuit. It converts, amplifies, filters, and standardizes the weak induced current signal, ultimately outputting a stable 0V to 5V standard analog voltage signal, along with overvoltage protection, adapting to remote terminal units and microprocessor-based protection devices in ring main units.

[0058] Secondly, a traveling wave ranging component 3 is configured, including a hollow core frame 31, a Rogowski coil 32, and an integral conditioning circuit. The hollow core frame 31 is coaxially arranged with the electromagnet core 21 and housed within the first cavity 13, ensuring consistent electromagnetic coupling with the primary busbar under test. The Rogowski coil 32 operates based on its principle, with a frequency response range covering power frequency to megahertz-level high-frequency signals. This allows for precise capture of transient traveling wave signals during faults while simultaneously sensing power frequency current signals. Furthermore, the differential current signal output by the Rogowski coil 32 is processed by the integral conditioning circuit. This includes integrating and restoring the differential signal using an active integrator constructed from a high-precision operational amplifier to obtain the true power frequency current waveform, and performing frequency domain separation via a bandpass filter, separating the power frequency signal from the high-frequency traveling wave signal. The high-frequency traveling wave signal retains its steep edge characteristics, providing a high-precision time-stamp signal for the traveling wave ranging algorithm, thereby achieving accurate location of fault points in the distribution network.

[0059] Secondly, by setting up shielding components, including a magnetic circuit shielding layer, a housing shielding layer, and a twisted pair shielding layer, external electromagnetic interference is protected and isolated, thereby effectively ensuring stable signal transmission.

[0060] Finally, it is worth noting that the current measurement and traveling wave ranging sensor described in this embodiment integrates the current measurement component 2 and the traveling wave ranging component 3 coaxially within the same openable housing 1, solving the problems of large space occupation, complex installation, and inconsistent electromagnetic coupling associated with traditional separate installations. Simultaneously, it ensures that the time-marked signal of the traveling wave ranging and the phase reference of the current measurement are physically homologous, eliminating phase difference correction errors common in separate installations and improving ranging accuracy. Furthermore, the traveling wave ranging component 3 provides redundancy for the current measurement component 2. If the current measurement component 2 fails, the traveling wave ranging component 3, operating based on the Rogowski coil 32 principle, can still provide current information with a certain degree of accuracy. Conversely, if the traveling wave ranging component 3 malfunctions, the current measurement component 2, operating based on the LPCT principle, ensures the maintenance of basic current measurement functionality.

[0061] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An open-type integrated current measurement and traveling wave ranging sensor for ring main units, characterized in that, It includes a housing (1), a current measurement component (2), and a traveling wave ranging component (3); wherein, The outer shell (1) includes a first body (11) and a second body (12); the first body (11) is rotatably openable and rotatably closed relative to the second body (12); the first body (11) is rotatably closed relative to the second body (12) to dock and form a circumferentially closed first cavity (13) and second cavity (14). The first cavity (13) is sleeved on the outside of the second cavity (14); the first cavity (13) is provided with the current measuring component (2) and the traveling wave ranging component (3); the second cavity (14) is axially through for the busbar to be measured to pass through; The current measurement component (2) is used to sense the power frequency current signal in the busbar under test in order to achieve accurate measurement of the power frequency current of the busbar under test. The traveling wave ranging component (3) is used to simultaneously sense the power frequency current signal and the fault transient traveling wave signal in the bus under test, and after being separated by integral filtering, it provides a high-precision time stamp signal for the traveling wave ranging algorithm.

2. The current measurement and traveling wave ranging sensor as described in claim 1, characterized in that, Both the first body (11) and the second body (12) include an outer wall panel (15), an inner wall panel (16), and a bottom wall panel (17) connecting the outer wall panel (15) and the inner wall panel (16); wherein, The first cavity (13) is formed between the outer wall plate (15), the inner wall plate (16) and the bottom wall plate (17), and the second cavity (14) is formed by the inner wall plate (16).

3. The current measurement and traveling wave ranging sensor as described in claim 2, characterized in that, The current measurement component (2) includes an electromagnet core (21), a secondary winding coil (22), and a signal conversion module; wherein, The electromagnet core (21) includes a movable section (211) and a fixed section (212); the movable section (211) and the fixed section (212) are respectively embedded in the first body (11) and the second body (12), and the movable section (211) and the fixed section (212) are connected to form a complete electromagnetic path; The secondary winding coil (22) is wound on the outer surface of the electromagnet core (21) to form an electromagnetic induction zone; The signal conversion module is electrically connected to the lead wire of the secondary winding coil (22).

4. The current measurement and traveling wave ranging sensor as described in claim 3, characterized in that, The signal conversion module includes a current-to-voltage converter and a signal amplification circuit; wherein... The current-to-voltage converter is used to convert the weak current signal output by the induction winding module into a voltage signal; The signal amplification circuit is used to amplify, filter and standardize the voltage signal obtained by the current-to-voltage converter to output a stable 0V to 5V standard voltage signal. The signal conversion module has a built-in overvoltage protection circuit to prevent secondary side overvoltage from damaging the equipment.

5. The current measurement and traveling wave ranging sensor as described in claim 3, characterized in that, The traveling wave ranging component (3) includes a hollow core frame (31), a Rogowski coil (32), and an integral conditioning circuit; wherein, The hollow skeleton (31) and the electromagnet core (21) are arranged coaxially and are placed together in the first cavity (13); The hollow skeleton (31) includes a first part (311) and a second part (312), which are joined and closed. The Rogowski coil (32) is uniformly wound on the outer surface of the hollow skeleton (31); The integral conditioning circuit is electrically connected to the output terminal of the Rogowski coil (32).

6. The current measurement and traveling wave ranging sensor as described in claim 5, characterized in that, The integral conditioning circuit includes an active integrator and a bandpass filter; wherein... The active integrator is used to integrate and restore the differential current signal output by the Rogowski coil (32) to obtain the real power frequency current waveform; The bandpass filter is used to separate the power frequency signal and the high-frequency traveling wave signal from the integrated signal, and retains the steep edge characteristics of the high-frequency traveling wave, providing a high-precision time-stamp signal for the traveling wave ranging algorithm.

7. The current measurement and traveling wave ranging sensor as described in claim 1, characterized in that, The output signals of the current measurement component (2) and the traveling wave ranging component (3) are transmitted to the RTU, microcomputer protection device and traveling wave ranging host of the ring network cabinet respectively through multi-core shielded twisted pair cable (9); The multi-core shielded twisted pair (9) includes a measurement-level output pair, a traveling wave ranging power frequency output pair, and a traveling wave ranging high frequency output pair; The measurement stage output line pair is used to transmit the 0-5V analog voltage signal output by the current measurement component (2); the traveling wave ranging power frequency output line pair is used to transmit the restored power frequency current signal output by the traveling wave ranging component (3); the traveling wave ranging high frequency output line pair is used to transmit the high frequency traveling wave signal output by the traveling wave ranging component (3).

8. The current measurement and traveling wave ranging sensor as described in claim 7, characterized in that, The outer casing (1) is equipped with terminals (6) for connecting the measurement stage output pairs, the traveling wave ranging power frequency output pairs, the traveling wave ranging high frequency output pairs, and the grounding wire.

9. The current measurement and traveling wave ranging sensor as described in claim 1, characterized in that, The space between the outer casing (1), the current measuring component (2), and the traveling wave ranging component (3) is filled with insulating material (7) to provide insulation protection and vibration protection.

10. The current measurement and traveling wave ranging sensor as described in claim 3, characterized in that, It also includes shielding components to prevent external electromagnetic interference and ensure stable signal transmission. The shielding assembly includes a magnetic circuit shielding layer, a housing shielding layer, and a twisted-pair shielding layer; wherein... The magnetic circuit shielding layer includes a permalloy strip covering the outside of the electromagnet core (21) and the secondary winding coil (22); the shell shielding layer includes a conductive copper mesh layer covering the inner surface of the outer wall plate (15); the first body (11) and the second body (12) are connected to achieve electrical connection to form a complete annular shielding cavity; the twisted pair shielding layer includes aluminum foil covering the outside of the measurement stage output line pair, the traveling wave ranging power frequency output line pair and the traveling wave ranging high frequency output line pair.

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