Method and system for distributing partial discharge sensors in high-voltage switchgear

Abstract

The present invention discloses a method and system for distributing partial discharge sensors in a high-voltage switchgear. The method comprises determining, for each partial discharge source, a location for the partial discharge sensor to be installed on the switchgear; evaluating the spatial radiation amplitude at each location to be installed based on the spatial electromagnetic field generated by the partial discharge source; selecting several locations to be installed with larger spatial radiation amplitudes as locations to be optimized, distributing partial discharge sensors therein, and normalizing the signal amplitudes of each channel of the partial discharge sensors to obtain a normalized measurement value for each channel of each partial discharge sensor; calculating an average normalized measurement value of each partial discharge sensor based on the normalized measurement values ​​of different channels of each partial discharge sensor, and selecting several locations with larger average normalized measurement values ​​as optimized placement locations; utilizing the optimized placement locations of the partial discharge sensors to more accurately detect and locate the partial discharge source in the switchgear.

Description

Technical Field

[0001] The present invention relates to the technical field of switch cabinets, and in particular to a method and system for distributing partial discharge sensors in high-voltage switch cabinets. Background Art

[0002] High-voltage switchgear is a complete set of equipment, primarily switches, assembled from primary and secondary equipment according to a specific circuit scheme. It is a crucial component of power transmission and distribution systems, primarily controlling and distributing high-voltage power signals. High-voltage switchgear operates under high voltage and high field strength conditions, and is subject to environmental influences such as condensation and dust, which can cause localized insulation degradation, leading to uneven electric field distribution. When the electric field strength reaches the breakdown field strength at that location, partial discharge (PD) occurs. Partial discharge monitoring of high-voltage switchgear is particularly important, not only effectively evaluating insulation condition but also enabling early detection of insulation problems.

[0003] However, due to the weak signal strength of partial discharge (PD), on-site detection is difficult. Therefore, selecting appropriate sensor locations is crucial for improving detection accuracy and effectiveness. Existing PD sensor placement is often determined based on experience and expert judgment, lacking scientific quantitative analysis and optimization methods. This approach is susceptible to subjective interference, making it difficult to ensure the scientific and reliable placement of sensors.

[0004] Currently, research is underway on switchgear temperature, electromagnetic distribution, and electrodynamic conditions. These factors, including their impact on temperature and stress, are analyzed to guide the optimal placement of various sensors. This approach to PD sensor placement is more advanced and convenient. However, these methods often blindly prioritize sensor placement, often installing them in easily accessible locations. However, due to the relatively complex internal structure of the switchgear, the detection performance of sensors in these locations may not be ideal. This irrational placement strategy also leads to high deployment costs. Furthermore, PD characteristics vary across different equipment, operating conditions, and fault modes, leading to significant variations in PD sensor placement performance across different equipment. Switchgear from different manufacturers and models has significant size variations and internal structures. The complex internal structure of switchgear also leads to significant attenuation of PD signals as they propagate between different compartments within the switchgear. Improper placement may result in undetectable PD signals. Therefore, customized placement is necessary for each device. Current PD sensor placement methods, however, fail to optimize individual placement for each device, resulting in significant variability in placement performance. Therefore, a universal sensor placement method is unavailable.

[0005] In related technology, patent application publication number CN104950233A proposes a method for locating and reconstructing partial discharge (PD) sources in switchgear based on the inverse field source problem. This method uses a time-varying electric dipole radiation model to construct and solve a FDTD (Digital Directional Dimension) (FDTD) computational model for the switchgear. This method can locate discharges occurring in the trolley compartment or busbar compartment, but its accuracy depends on the sensor placement. When the sensor is installed outside the cable compartment, the signal generated by partial discharges in the trolley compartment or busbar compartment may not propagate to the sensor, allowing for location. The article "Simulation Study on the Propagation Characteristics of Transient Ground Voltage Caused by Partial Discharge in Switchgear," High Voltage Technology, Wang Youyuan et al., examines the generation mechanism of transient ground voltage in detail based on fundamental electromagnetic principles. The article simulates and analyzes the relationship between the transient ground voltage amplitude and the excitation source pulse width, excitation source pulse amplitude, and the distance between the measuring device and the excitation source. This method provides a reference for the selection of sensor location layout scheme from a mechanism level. However, in actual operation, the complex internal structure of the switch cabinet will significantly interfere with the signal propagation phenomenon. Therefore, it is necessary to use experimental trial methods to obtain the optimal sensor layout position.

[0006] Therefore, developing a method for optimizing the placement of partial discharge sensors in high-voltage switchgear has important significance and application value. Summary of the Invention

[0007] The technical problem to be solved by the present invention is how to optimize the layout positions of partial discharge sensors.

[0008] The present invention solves the above technical problems through the following technical means:

[0009] The present invention proposes a method for distributing partial discharge sensors in a high-voltage switch cabinet, the method comprising:

[0010] For each partial discharge source, determine the location where the partial discharge sensor is to be installed on the switchgear;

[0011] Using the local discharge source as a dipole, and evaluating the spatial radiation amplitude at each to-be-installed position based on the spatial electromagnetic field generated by the local discharge source;

[0012] Selecting several locations to be installed with larger spatial radiation amplitudes as locations to be optimized and arranging partial discharge sensors therein, and normalizing the signal amplitudes of each channel of the partial discharge sensors to obtain normalized measurement values ​​of each channel of each partial discharge sensor;

[0013] Based on the normalized measurement values ​​of different channels of each partial discharge sensor, an average normalized measurement value of each partial discharge sensor is calculated, and several positions with larger average normalized measurement values ​​are selected as optimized layout positions, wherein each of the partial discharge sensors is arranged at each position to be optimized corresponding to each of the partial discharge sources.

[0014] Furthermore, the spatial electromagnetic field generated by the local discharge source is publicly expressed as:

[0015]

[0016] Where: E θ is the spatial electric field generated by the partial discharge power source; H Φ is the spatial magnetic field generated by the partial discharge power source; θ is the radiation angle; r is the distance between the installation location and the partial discharge source; j is the imaginary unit; w is the angular frequency; I is the current; L is the dipole spacing; e -jkr is the phase factor.

[0017] Furthermore, the partial discharge sensor is a three-in-one partial discharge sensor.

[0018] Furthermore, when the three-in-one partial discharge sensor is arranged at the position to be optimized, the UHF antenna and the ultrasonic sensor are arranged facing the space inside the cabinet, and the TEV antenna is attached to the cabinet body.

[0019] Furthermore, the local discharge source includes a tip discharge source, a metal discharge source and a suspended discharge source;

[0020] The locations where the partial discharge sources are arranged include a busbar room, a cable room and a trolley room.

[0021] In addition, the present invention also proposes a high-voltage switchgear partial discharge sensor distribution system, the system comprising:

[0022] A module for determining a location to be installed, for determining a location to be installed of a partial discharge sensor on the switchgear for each partial discharge source;

[0023] a spatial radiation amplitude evaluation module, configured to evaluate the spatial radiation amplitude at each to-be-installed position based on the spatial electromagnetic field generated by the partial discharge source, using the partial discharge source as a dipole;

[0024] An installation and measurement module is used to select several locations to be installed with large spatial radiation amplitudes as locations to be optimized and arrange partial discharge sensors, and normalize the signal amplitudes of each channel of the partial discharge sensor to obtain a normalized measurement value of each channel of each partial discharge sensor;

[0025] A placement optimization module is configured to calculate an average normalized measurement value of each partial discharge sensor based on the normalized measurement values ​​of different channels of each partial discharge sensor, and select several locations with larger average normalized measurement values ​​as optimized placement locations, wherein each of the partial discharge sensors is arranged at each location to be optimized corresponding to each of the partial discharge sources.

[0026] Furthermore, the formula for the spatial electromagnetic field generated by the local discharge source is expressed as:

[0027]

[0028] Where: E θ is the spatial electric field generated by the partial discharge power source; H Φ is the spatial magnetic field generated by the partial discharge power source; θ is the radiation angle; r is the distance between the installation location and the partial discharge source; j is the imaginary unit; w is the angular frequency; I is the current; L is the dipole spacing; e -jkr is the phase factor.

[0029] Furthermore, the partial discharge sensor is a three-in-one partial discharge sensor.

[0030] Furthermore, when the three-in-one partial discharge sensor is arranged at the position to be optimized, the UHF antenna and the ultrasonic sensor are arranged facing the space inside the cabinet, and the TEV antenna is attached to the cabinet body.

[0031] Furthermore, the local discharge source includes a tip discharge source, a metal discharge source and a suspended discharge source;

[0032] The locations where the partial discharge sources are arranged include a busbar room, a cable room and a trolley room.

[0033] The advantages of the present invention are:

[0034] (1) Since the partial discharge in the high-voltage switchgear is very weak, it is difficult to capture the discharge signal when the sensor layout position is not ideal. The present invention regards the partial discharge source as a dipole and optimizes the layout position of the partial discharge sensor according to the spatial electromagnetic field generated by the partial discharge source. This can more accurately detect and locate the partial discharge source in the switchgear, improve the monitoring effect and accuracy, and is of great significance for ensuring the safe operation of power equipment and extending the equipment life.

[0035] (2) Since the data collected by the three-in-one sensor includes three channels: UHF, TEV and ultrasonic monitoring, and the signals of each channel have different dimensions, the present invention uses a normalization method to process the signal, so that the absolute value of the physical system value becomes a relative value relationship, eliminating the dimensional influence between indicators to achieve data standardization processing, thereby solving the comparability problem between data indicators.

[0036] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a flow chart of a method for distributing partial discharge sensors in a high-voltage switchgear cabinet, as proposed in an embodiment of the present invention;

[0038] Figure 2 is the spatial radiation pattern of the electric dipole in an embodiment of the present invention;

[0039] Figure 3 This is a structural diagram of a three-in-one partial discharge sensor for time domain waveform measurement according to an embodiment of the present invention;

[0040] Figure 4 Schematic diagram of the tip discharge position in an embodiment of the present invention, (a) is the tip discharge position 1, (b) is the tip discharge position 2, and (c) is the tip discharge position 3;

[0041] Figure 5 This is the time domain waveform at the tip discharge position 1 in the embodiment of the present invention;

[0042] Figure 6 This is the time domain waveform at the tip discharge position 2 in the embodiment of the present invention;

[0043] Figure 7 This is the time domain waveform at the tip discharge position 3 in the embodiment of the present invention;

[0044] Figure 8 This is a structural diagram of a partial discharge sensor distribution system for a high-voltage switchgear proposed in an embodiment of the present invention. DETAILED DESCRIPTION

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0046] like Figure 1 As shown, a method for distributing partial discharge sensors in a high-voltage switch cabinet is proposed in a first embodiment of the present invention. The method includes the following steps:

[0047] S10. For each partial discharge source, determining a location on the switchgear where the partial discharge sensor is to be installed;

[0048] S20, using the local discharge source as a dipole, and evaluating the spatial radiation amplitude at each to-be-installed position based on the spatial electromagnetic field generated by the local discharge source;

[0049] It should be noted that this embodiment considers the partial discharge signal generated by the partial discharge source as a transient electromagnetic process to establish a pulse discharge model. Based on electromagnetic field theory and propagation characteristics, the electromagnetic radiation field in space is established, and the measurement signal at the location where each sensor is to be installed is evaluated. By setting different excitation source positions, the sensitivity and coverage of the sensor are simulated and analyzed.

[0050] S30, selecting several locations to be installed with larger spatial radiation amplitudes as locations to be optimized and arranging partial discharge sensors therein, and normalizing the signal amplitudes of each channel of the partial discharge sensors to obtain normalized measurement values ​​of each channel of each partial discharge sensor;

[0051] It should be noted that the spatial radiation amplitudes at the locations to be installed can be sorted from large to small, and the locations to be installed corresponding to the first several spatial radiation amplitudes can be selected as the locations to be optimized according to the sorting results, and partial discharge sensors can be arranged at the locations to be optimized.

[0052] Specifically, this embodiment selects the positions to be installed corresponding to the first 7 spatial radiation amplitudes. Those skilled in the art can select a specific number of positions to be installed according to actual conditions, and this embodiment does not make any specific limitation.

[0053] It should be noted that since the signals of each channel of the partial discharge sensor have different dimensions, it is necessary to use a normalization method to process the signals so that the absolute values ​​of the physical system values ​​become a certain relative value relationship, eliminate the dimensional influence between indicators to achieve data standardization processing, and thus solve the comparability problem between data indicators.

[0054] S40. Calculate an average normalized measurement value of each partial discharge sensor based on the normalized measurement values ​​of different channels of each partial discharge sensor, and select several locations with larger average normalized measurement values ​​as optimized location locations, wherein each partial discharge sensor is arranged at each location to be optimized corresponding to each partial discharge source.

[0055] It should be noted that this embodiment regards the PD source as a dipole. Based on the spatial electromagnetic field generated by the PD source, the location of the PD sensor is optimized. This can more accurately detect and locate the PD source in the switchgear, improve the monitoring effect and accuracy, and is of great significance for ensuring the safe operation of power equipment and extending the equipment life.

[0056] In one embodiment, the spatial electromagnetic field generated by the local discharge source is expressed as:

[0057]

[0058] Where: E θ is the spatial electric field generated by the partial discharge power source; H Φ is the spatial magnetic field generated by the partial discharge power source; θ is the radiation angle; r is the distance between the installation location and the partial discharge source; j is the imaginary unit; w is the current frequency; I is the current; L is the dipole distance; e -jkr is the phase factor

[0059] Specifically, by considering the PD source as a dipole, the spatial electromagnetic field generated by the PD point source is derived based on the dipole radiation field formula. The electromagnetic far-field calculation formula of the current element in the spherical coordinate system is:

[0060]

[0061]

[0062] Where: Z0 is the spatial wave impedance; r is the distance between the observation point and the current source; dl is the length of the current element; H Φ It is the spatial magnetic field generated by the partial discharge power supply.

[0063] The angle θ and the distance r both change with the z position, and can be approximated in the far field, namely:

[0064]

[0065] sinθ(z)≈sinθ0

[0066]

[0067] Where r0 and θ0 are the reference distance and reference angle

[0068] Cancel phase factor So we have:

[0069]

[0070] Where I0 is the current.

[0071] In spherical coordinates, it is expressed in component form as:

[0072]

[0073]

[0074] In the far field, and The higher-order terms can be ignored, so the above formula can be simplified to the partial discharge space electromagnetic radiation, as shown below:

[0075]

[0076] In one embodiment, the partial discharge sensor is a three-in-one partial discharge sensor.

[0077] Furthermore, the three-in-one partial discharge sensor includes three channels: UHF, TEV and ultrasonic monitoring. When the three-in-one partial discharge sensor is arranged at the position to be optimized, the UHF antenna and ultrasonic sensor are arranged facing the space inside the cabinet, and the TEV antenna is attached to the cabinet body.

[0078] By arranging the UHF antenna and ultrasonic wave facing the space inside the cabinet, the UHF and ultrasonic signals can be effectively detected. The TEV antenna is attached to the cabinet to effectively detect the ground wave signal.

[0079] In one embodiment, the local discharge source includes a tip discharge source, a metal discharge source, and a suspended discharge source;

[0080] The locations where the partial discharge sources are arranged include a busbar room, a cable room and a trolley room.

[0081] This embodiment simulates tip discharge, metal discharge, and suspended discharge in the busbar compartment, cable compartment, and trolley compartment of a laboratory switchgear, and records the amplitude of each sensor signal. Those skilled in the art may also install different types of partial discharge sources in other locations of the switchgear according to actual circumstances, and this embodiment does not specifically limit this.

[0082] Specifically, this embodiment uses the partial discharge space electromagnetic radiation formula to calculate the distribution of the electromagnetic field generated by the partial discharge source in space. Figure 2 As shown in the figure, according to the simulation results, UHF, TEV and ultrasonic monitoring three-in-one sensors are arranged at the seven locations with the largest spatial radiation amplitude in the switch cabinet. The connection method of the three-in-one sensor is as follows: Figure 3 shown.

[0083] Simulate tip discharge in the laboratory switch cabinet busbar room, cable room, and trolley room, record the signal amplitude of each sensor, compare the signal strength of each channel, and process the test data. Figure 4 As shown, when the tip discharge occurs at position 1, position 2 and position 3 respectively, the signal time domain waveform is as follows Figure 5 、 Figure 6 and Figure 7 As shown in the figure, channel A measures TEV signals, channel B measures UHF signals, channel C measures ultrasonic signals, and channel D measures pulsed current signals. Because the three-in-one sensor collects data from three channels, including UHF, TEV, and ultrasonic monitoring, and the signals in each channel have different dimensions, a normalization method is required to process the signals. The normalization results are shown in Table 1.

[0084] Table 1

[0085]

[0086] Calculate the average of the normalized values ​​of different channels of the same sensor at different discharge positions, and find 2 to 3 positions with larger average normalized values. Specifically, find the maximum normalized average values ​​of the three positions, which are position 2: 0.6536, position 6: 0.6633, and position 7: 0.5805. This screens out the best positions for sensor placement as positions 2, 6, and 7.

[0087] like Figure 8 As shown, the second embodiment of the present invention further provides a high-voltage switch cabinet partial discharge sensor distribution system, the system comprising:

[0088] The module 10 for determining the position to be installed is used to determine the position to be installed of the partial discharge sensor on the switch cabinet for each partial discharge source;

[0089] a spatial radiation amplitude evaluation module 20 for evaluating the spatial radiation amplitude at each to-be-installed position based on the spatial electromagnetic field generated by the local discharge source, using the local discharge source as a dipole;

[0090] The installation and measurement module 30 is used to select several locations to be installed with large spatial radiation amplitudes as locations to be optimized and arrange partial discharge sensors therein, and normalize the signal amplitudes of each channel of the partial discharge sensors to obtain normalized measurement values ​​of each channel of each partial discharge sensor;

[0091] The placement optimization module 40 is configured to calculate an average normalized measurement value of each partial discharge sensor based on the normalized measurement values ​​of different channels of each partial discharge sensor, and select several locations with larger average normalized measurement values ​​as optimized placement locations, wherein each partial discharge sensor is arranged at each location to be optimized corresponding to each partial discharge source.

[0092] In one embodiment, the spatial electromagnetic field generated by the local discharge source is expressed as:

[0093]

[0094] Where: E θ is the spatial electric field generated by the partial discharge power source; H Φ is the spatial magnetic field generated by the partial discharge power source; θ is the radiation angle; r is the distance between the installation location and the partial discharge source; j is the imaginary unit; w is the angular frequency; I is the current; L is the dipole spacing; e -jkr Phase factor.

[0095] In one embodiment, the partial discharge sensor is a three-in-one partial discharge sensor.

[0096] In one embodiment, when the three-in-one partial discharge sensor is arranged at the position to be optimized, the UHF antenna and the ultrasonic sensor are arranged facing the space inside the cabinet, and the TEV antenna is attached to the cabinet body.

[0097] In one embodiment, the local discharge source includes a tip discharge source, a metal discharge source, and a suspended discharge source;

[0098] The locations where the partial discharge sources are arranged include a busbar room, a cable room and a trolley room.

[0099] It should be noted that other embodiments or implementation methods of the high-voltage switchgear partial discharge sensor distribution system of the present invention can refer to the above-mentioned method embodiments, which will not be repeated here.

[0100] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0101] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0102] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for distributing partial discharge sensors in a high-voltage switchgear, characterized in that: The method comprises: For each partial discharge source, determining a location on the switch cabinet where a partial discharge sensor is to be installed, wherein the partial discharge sensor is a three-in-one partial discharge sensor; The local discharge source is used as a dipole, and the spatial radiation amplitude at each to-be-installed position is evaluated based on the spatial electromagnetic field generated by the local discharge source, wherein the spatial electromagnetic field generated by the local discharge source is publicly expressed as: Where: E θ is the spatial electric field generated by the partial discharge power source; H Φ is the spatial magnetic field generated by the partial discharge power source; θ is the radiation angle; r is the distance between the installation location and the partial discharge source; j is the imaginary unit; w is the angular frequency; I is the current; L is the dipole spacing; e -jkr is the phase factor; Selecting several locations to be installed with larger spatial radiation amplitudes as locations to be optimized and arranging partial discharge sensors therein, and normalizing the signal amplitudes of each channel of the partial discharge sensors to obtain normalized measurement values ​​of each channel of each partial discharge sensor; Based on the normalized measurement values ​​of different channels of each partial discharge sensor, an average normalized measurement value of each partial discharge sensor is calculated, and several positions with larger average normalized measurement values ​​are selected as optimized layout positions, wherein each of the partial discharge sensors is arranged at each position to be optimized corresponding to each of the partial discharge sources.

2. The method for distributing partial discharge sensors in a high-voltage switch cabinet according to claim 1, wherein: When the three-in-one partial discharge sensor is arranged at the position to be optimized, the UHF antenna and the ultrasonic sensor are arranged facing the space inside the cabinet, and the TEV antenna is attached to the cabinet body.

3. The method for distributing partial discharge sensors in a high-voltage switch cabinet according to claim 1, wherein: The local discharge source includes a tip discharge source, a metal discharge source and a suspended discharge source; The locations where the partial discharge sources are arranged include a busbar room, a cable room and a trolley room.

4. A high-voltage switchgear partial discharge sensor distribution system, characterized in that: The system comprises: A module for determining a location to be installed, for determining a location to be installed of a partial discharge sensor on the switch cabinet for each partial discharge source, wherein the partial discharge sensor is a three-in-one partial discharge sensor; A spatial radiation amplitude assessment module is configured to assess the spatial radiation amplitude at each to-be-installed position based on the spatial electromagnetic field generated by the partial discharge source, using the partial discharge source as a dipole. The spatial electromagnetic field generated by the partial discharge source is expressed as follows: Where: E θ is the spatial electric field generated by the partial discharge power source; H Φ is the spatial magnetic field generated by the partial discharge power source; θ is the radiation angle; r is the distance between the installation location and the partial discharge source; j is the imaginary unit; w is the angular frequency; I is the current; L is the dipole spacing; e -jkr is the phase factor; An installation and measurement module is used to select several locations to be installed with large spatial radiation amplitudes as locations to be optimized and arrange partial discharge sensors, and normalize the signal amplitudes of each channel of the partial discharge sensor to obtain a normalized measurement value of each channel of each partial discharge sensor; A placement optimization module is configured to calculate an average normalized measurement value of each partial discharge sensor based on the normalized measurement values ​​of different channels of each partial discharge sensor, and select several locations with larger average normalized measurement values ​​as optimized placement locations, wherein each of the partial discharge sensors is arranged at each location to be optimized corresponding to each of the partial discharge sources.

5. The high-voltage switchgear partial discharge sensor distribution system according to claim 4, characterized in that: When the three-in-one partial discharge sensor is arranged at the position to be optimized, the UHF antenna and the ultrasonic sensor are arranged facing the space inside the cabinet, and the TEV antenna is attached to the cabinet body.

6. The high-voltage switchgear partial discharge sensor distribution system according to claim 4, characterized in that: The local discharge source includes a tip discharge source, a metal discharge source and a suspended discharge source; The locations where the partial discharge sources are arranged include a busbar room, a cable room and a trolley room.

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