A method for online monitoring and positioning of partial discharge of large generators

Abstract

The present invention relates to an online monitoring and positioning method for partial discharge of a large generator, comprising the steps of: using computational programming to implement matrix iteration calculations and developing a corresponding software interface; using the time delay of four pulse sequence signals at the same time point to determine the location of the discharge source, displaying and comparing the pulse time difference on the same interface, the shorter the time for the pulse sequence signal to reach the corresponding sensor, the more likely the discharge source is located in the block where the sensor that sends the pulse sequence signal is located. The beneficial effects of the present invention are: providing an online monitoring system for partial discharge of a large generator, the system is provided with four sensors and a data concentration processor for evaluating the overall insulation condition of the generator, and is also provided with a transition module and a controller; used to predict the degree of cracking and positioning of internal insulation components in advance, saving a lot of maintenance time for operation and maintenance personnel.

Description

Technical Field

[0001] The invention belongs to the technical field of insulation monitoring of large generators, and in particular relates to an online monitoring and positioning method for partial discharge of a generator based on a broadband built-in sensor. Background Art

[0002] Generators play a vital role in the operation of power grids. They are responsible for the conversion of other energy sources into electric energy and are the starting point of electric energy transmission. Therefore, whether the generator operates normally plays a vital role in the entire process of power grid transmission. The insulation monitoring research of generators is an important part of maintaining the operation of generators. Among them, the partial discharge parameter is the only direct parameter to measure the insulation state of the generator. Especially for the stator coils of large generators of 6kV and above, partial discharge may occur inside and on the surface of the insulation during operation. Moreover, as the voltage level increases, the more serious the partial discharge, the greater the destructiveness. According to statistics, about 50% of motor damage accidents are caused by insulation damage of the motor stator winding, and most of the insulation damage of the stator winding is caused by long-term partial discharge inside. Therefore, online monitoring of partial discharge of generators is of great significance for the stable operation of generators and early prediction of accidents.

[0003] At present, the online monitoring of partial discharge of generators is mainly carried out by external sensors, including:

[0004] First, two capacitive VHF sensors are connected in parallel on each phase of the generator output bus, namely the near-end sensor and the far-end sensor. The frequency band is generally tens of megahertz to hundreds of megahertz, and the direction of the discharge source is determined by pulse delay. This method can determine whether the discharge source comes from inside the generator, which is suitable for online monitoring. However, it does not have the function of locating the internal discharge source of the generator. In addition, the sensors are connected in parallel on the output bus, which requires high reliability of the sensors. If the internal coupling capacitor is short-circuited, it will directly affect the operation of the generator, resulting in sudden power outages.

[0005] Second, install HFCT sensors at the neutral point of the generator. The frequency band is from hundreds of kilohertz to tens of megahertz. It mainly couples the high-frequency pulse current signal of the neutral point to achieve the purpose of monitoring the partial discharge of the generator. The advantage of this method is that the sensor is a through-core mutual inductance structure, and has no electrical connection with the generator, so it will not cause any impact on the generator. Its biggest disadvantage is that it is easily affected by electromagnetic interference outside the generator. In addition, when there is a small discharge source, it cannot be detected by the system due to severe signal attenuation.

[0006] Third, ultrasonic sensors are placed close to the generator casing. The frequency band is from tens of kilohertz to hundreds of kilohertz. They mainly couple the local discharge ultrasonic waves on the generator surface. They are highly safe and suitable for inspection. Multiple sensors can be used to locate the local discharge source. However, during testing, the generator's own vibration waves are strong, which often drown out the local discharge signal, causing the system to misjudge and fail to locate. It is also not suitable for long-term online monitoring.

[0007] Fourth, microstrip lines are installed in the slots of the generator, with frequencies ranging from tens of megahertz to hundreds of megahertz, to couple surface electromagnetic waves. Although this method is inside the generator, the pulse signal of the discharge source has fewer surface electromagnetic wave components. In addition, the location of the sensor has a great influence on the coupling effect of the signal.

[0008] In summary, except that the ultrasonic sensor method is not suitable for online monitoring, none of the several online monitoring methods have the function of locating the discharge source; therefore, it is particularly important to propose an online monitoring and locating method for partial discharge of large generators. Summary of the invention

[0009] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for online monitoring and positioning of partial discharge of a large generator.

[0010] The large-scale generator partial discharge online monitoring system comprises: four sensors, a generator body, a generator rotor, an upper cover, a base, a water wheel, a signal line, a transition module, a radio frequency cable, an analysis module, a data line, a central processing module, a data line and a display module; the four sensors are respectively sensor A, sensor B, sensor C and sensor D; the left and right sides of the upper cover of the generator body are respectively installed with sensor A and sensor D; the left and right sides of the base of the generator are respectively installed with sensor B and sensor C; the generator rotor is located inside the generator body, the water wheel is located below the generator body, and the water wheel is connected to the generator rotor; four signal lines are respectively connected to sensor A, sensor B, sensor C and sensor D, the four signal lines are connected to the transition module, the transition module is then connected to the analysis module through the radio frequency cable, the analysis module is then connected to the central processing module through the data line, and the central processing module is connected to the display module through the data line.

[0011] Preferably, the analysis module contains signal frequency selection, detection and amplification processing circuits; the sensor as a whole is a planar structure tightly attached to the insulating plate, and the insulating plate is respectively fixed on the upper cover and base of the generator. The output signal line of the sensor is routed along the ground potential of the generator casing, and is led out from the reserved outlet hole and connected to the transition module.

[0012] Preferably, the transition module contains a wideband matching circuit, which uses a gradient line and a non-inductive resistor and a capacitor connected in parallel.

[0013] Preferably, sensor A, sensor B, sensor C and sensor D are all pre-built into the generator; sensor A, sensor B, sensor C and sensor D are all unidirectional planar antenna sensors.

[0014] Preferably, the operating frequency band of sensor A, sensor B, sensor C and sensor D is 100 MHz to 3 GHz, and the standing wave ratio within the frequency band is less than 2.

[0015] The online monitoring method of the large-scale generator partial discharge online monitoring system specifically comprises the following steps:

[0016] Step 1: Use sensors (sensor A, sensor B, sensor C, sensor D) to couple the partial discharge signal in the generator internal space, and convert it into four-way broadband partial discharge signals (electromagnetic wave signals), and then connect them to the transition module through the UHF coaxial line. The controller controls the gain and bandwidth to make the signal achieve the best signal-to-noise ratio;

[0017] Step 2: After signal matching, signal filtering and signal amplification, the four-channel broadband partial discharge signals are divided into two channels, and then the two channels are connected to the analysis module:

[0018] After frequency selection, detection and amplification, a low-frequency envelope signal is obtained from one signal. Then, after the low-frequency envelope signal is digitized, the pulse identification of partial discharge is performed. If it is confirmed that the discharge is generated by the internal discharge source of the generator, the partial discharge signal quantity is divided, the real-time parameters of the partial discharge are calculated, and various spectra of the partial discharge parameters are formed. The various spectra and real-time quantities of the partial discharge parameters are sent to the data concentration processor for analysis, and then stored in the database and displayed. The data concentration processor controls the signal in the conditioning process through the controller according to the data characteristics of the final result after analysis.

[0019] Another signal forms a pulse sequence and enters the pulse sequence synchronization logic module for synchronous high-frequency acquisition, which can be used for interference source type identification or discharge source location algorithm; the data concentration processor issues a control command to determine whether to start synchronous acquisition of the pulse sequence: if the control command is yes, the discharge source location algorithm is started, the computer software calculates the discharge source position coordinate information, and the discharge source position coordinate information is fed back to the data concentration processor; if the control command is no, the interference source identification logic is entered.

[0020] Preferably, in step 2, the controller controls the signal in the following specific ways: filter band selection control, amplification gain control, frequency selection control, detection control and low-frequency amplification gain control.

[0021] The positioning algorithm of this large-scale generator partial discharge online monitoring system includes the following steps:

[0022] Step 1, use computational programming to implement matrix iteration calculation, and develop the corresponding software interface; divide the generator space into four blocks, upper left, upper right, lower left and lower right, and each block inside the generator contains a sensor; if the signal measured by the sensor is determined to be a partial discharge generated by the discharge source inside the generator, start the spatial positioning algorithm; the data centralized processing controller starts the synchronous acquisition command; four channels synchronously acquire four-way pulse sequence signals at a sampling rate of 1GM / s;

[0023] Step 2: Use the time delay of four pulse sequence signals at the same time point to determine the location of the discharge source. Display and compare the pulse time difference on the same interface. The shorter the time it takes for the pulse sequence signal to reach the corresponding sensor, the discharge source is located in the block where the sensor that sends the pulse sequence signal is located. Use the least squares calculation method and matrix iteration to calculate the spatial coordinate position of the discharge source.

[0024] Preferably, step 2 specifically comprises the following steps:

[0025] Step 2.1. Establish a three-dimensional model according to the actual size of the generator body and configure the position coordinate information of the four sensors: treat the generator as a cube model with coordinates, determine the cube coordinates according to the actual size of the generator, and mark the three-dimensional coordinates of the cube, where the source coordinates are Q (x, y, z), and the four sensor coordinates are: upper left sensor Q1 (x1, y1, z1), upper right sensor Q2 (x2, y2, z2), lower left sensor Q3 (x3, y3, z3), and lower right sensor Q4 (x4, y4, z4);

[0026] Step 2.2, the transmission rate of the discharge electromagnetic wave inside the generator is v; suppose the propagation time of the electromagnetic wave generated by the discharge source to the four sensors is t1, t2, t3, t4 respectively; then the distance equations from the discharge source Q to the sensor Q1, sensor Q2, sensor Q3 and sensor Q4 are:

[0027]

[0028] In the above formula, f1(x,y,z,t) is the distance from the discharge source Q to the sensor Q1, f2(x,y,z,t) is the distance from the discharge source Q to the sensor Q2, f3(x,y,z,t) is the distance from the discharge source Q to the sensor Q3, and f4(x,y,z,t) is the distance from the discharge source Q to the sensor Q4; v is the transmission rate of the discharge electromagnetic wave inside the generator;

[0029] Step 2.3: Let Δt 12Δt is the time difference between the electromagnetic wave generated by the discharge source reaching the upper right sensor Q2 (x2, y2, z2) and the upper left sensor Q1 (x1, y1, z1); 13 Δt is the time difference between the electromagnetic wave generated by the discharge source reaching the lower left sensor Q3 (x3, y3, z3) and the upper left sensor Q1 (x1, y1, z1); 14 is the time difference between the electromagnetic wave generated by the discharge source reaching the lower right sensor Q4 (x4, y4, z4) and the upper left sensor Q1 (x1, y1, z1), then

[0030]

[0031] In the above formula, t2, t3, and t4 are the propagation times of the electromagnetic waves generated by the discharge source to the upper right sensor Q2 (x2, y2, z2), the lower left sensor Q3 (x3, y3, z3), and the lower right sensor Q4 (x4, y4, z4), respectively; where Δt 12 , Δt 13 , Δt 14 Synchronously collect the calculated parameters for the online monitoring system;

[0032] Introducing vector representation, let:

[0033]

[0034] Then, equations (1), (3), (4) and (5) are transformed into:

[0035] f(x,y,z,t)=0 (6)

[0036] Step 2.4: Use the iterative formula (7) to iterate the formula (6) through computer software to obtain the approximate value of the position coordinate Q (x, y, z) parameter as the spatial coordinate position of the discharge source:

[0037]

[0038] In the above formula (7):

[0039]

[0040] Transform equation (8) and equation (9) into:

[0041]

[0042] Among them [A T K A K ] * For [A T K A K ] is the adjoint matrix of .

[0043] The beneficial effects of the present invention are as follows: the present invention provides an online monitoring system for partial discharge of a large generator, which is provided with four sensors and a data concentration processor for evaluating the overall insulation condition of the generator, and is also provided with a transition module and a controller; it is used to predict the degree of cracking and positioning of internal insulating components in advance, saving a lot of maintenance time for operation and maintenance personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is the structure diagram of the generator partial discharge online monitoring system;

[0045] Figure 2 It is a flow chart of the on-line monitoring method of partial discharge of generator;

[0046] Figure 3 This is a model diagram of local discharge source location for block-type generators;

[0047] Figure 4 To synchronously collect the time domain pulse diagram of four signals;

[0048] Figure 5 The coordinate diagram of the four sensors for the internal discharge source distance of the generator;

[0049] Figure 6 (a) is a three-dimensional graph of the test results of one signal from the upper left sensor for 50 power frequency cycles; (b) is a Q-Φ graph of the test results of one signal from the upper left sensor for 50 power frequency cycles; (c) is an N-Φ graph of the test results of one signal from the upper left sensor for 50 power frequency cycles; (d) is an NQ graph of the test results of one signal from the upper left sensor for 50 power frequency cycles.

[0050] Explanation of the reference numerals: sensor A1, sensor B2, sensor C3, sensor D4, generator body 5, generator rotor 6, generator cover 7, base 8, water wheel 9, signal line 10, transition module 11, radio frequency cable 12, analysis module 13, first data line 14, central processing module 15, second data line 16, display module 17. DETAILED DESCRIPTION

[0051] The present invention is further described below in conjunction with embodiments. The description of the following embodiments is only used to help understand the present invention. It should be noted that for ordinary persons in the art, without departing from the principle of the present invention, the present invention can also be modified in some ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0052] In order to increase the accuracy of on-site testing, improve the anti-interference ability of the system, and realize the positioning function of the discharge source in the online monitoring system, the present invention proposes a local discharge monitoring and positioning method for generators based on built-in broadband sensors, so as to evaluate the overall insulation condition of the generator, predict the degree of cracking of internal insulation components in advance and locate them, so as to prevent the occurrence of shutdown accidents caused by insulation breakdown of the generator; the present invention also has a discharge source spatial positioning function; the present invention first obtains the discharge spectrum of the local discharge parameters of the generator according to the signal characteristics of the built-in broadband sensor through special signal processing and digital post-statistical analysis, and then starts the discharge source positioning function to perform preliminary and precise positioning of the discharge source inside the generator. The preliminary positioning is to apply the time arrival method of four sensor signals to determine the internal coordinate module of the generator to which the discharge source belongs; the precise positioning is to use the matrix iteration method to realize the approximate calculation of the spatial coordinates of the discharge source, thereby realizing the precise positioning of the discharge source, saving a lot of maintenance time for operation and maintenance personnel.

[0053] The broadband sensor of the present invention is specially made for realizing the online monitoring method, and the sensor is pre-built into the generator; each generator is equipped with 4 sensors, which are respectively located at the left and right positions of the upper cover, the left and right positions of the base of the generator, and can simultaneously receive the local discharge signal inside the generator, and is a unidirectional planar antenna sensor that can couple electromagnetic waves in space; the sensor response frequency band is 100MHz to 3GHz, and the standing wave ratio in the frequency band is less than 2. The average equivalent height in the frequency band detected by the GTM chamber is 11mm, which fully meets the needs of partial discharge signal testing. The sensor is in a planar structure as a whole and is closely attached to the insulating plate, and the insulating plate is respectively fixed on the upper cover and the base of the generator. The output signal line is routed along the ground potential of the generator shell, and is led out from the reserved outlet hole and connected to the transition module next to the generator. Since the generator is a fully enclosed structure, it can effectively shield external ultra-high frequency and UHF electromagnetic wave signals represented by wireless communication. The sensor itself can also effectively shield various radio interferences below 100MHz. Since the background noise is very small, the overall signal-to-noise ratio of the system is very high. Under laboratory conditions, when the distance to the discharge source is less than 1 meter and there is no partition in between, the minimum sensitivity of the system can reach 0.5pC, and the technical indicators fully meet the test needs.

[0054] Due to the wide bandwidth and high sensitivity of the signal output by the broadband sensor, the transition module connected to the sensor is required to be very different from the conventional processing method, such as Figure 2As shown, first, it contains a wide-band matching circuit, which is realized by a gradient line plus a non-inductive resistor and a capacitor in parallel; secondly, filtering and amplification also take into account the influence of the wide band, and the controller controls the gain and bandwidth to make the signal reach the best signal-to-noise ratio; secondly, two signals are output simultaneously: one is to the pulse sequence synchronization logic module for synchronous high-frequency acquisition, which can be used for interference source type discrimination or discharge source location algorithm; the other is collected after signal frequency selection, detection and amplification, and can finally be used for quantitative analysis of partial discharge, calculate the real-time parameters of partial discharge, and form various statistical spectra; finally, the data centralized processing controller further processes various types of data, stores them in the database and displays them, and controls other modules through the controller.

[0055] As an example, Figure 1 As shown in the figure, an experimental platform simulating a large generator was built in the laboratory. Figure 1 Fix and connect sensor A1, sensor B2, sensor C3, sensor D4 and generator partial discharge online monitoring system according to the requirements, and establish the following on-line monitoring system based on the actual size of the generator body on the computer software: Figure 3 The three-dimensional model is shown, and the coordinate values ​​of each sensor are marked, such as Figure 5 As shown, the upper left sensor is Q1 (1.5, 13.5, 26.3); the upper right sensor is Q2 (25.2, 17.2, 26.3); the lower left sensor is Q3 (1.8, 13.6, 1.7); the lower right sensor is Q4 (24.3, 16.1, 1.7), unit (m); in the setting of the computer software, the simulated discharge source model is placed in the upper left module of the generator; the discharge source coordinate point is Q (3.2, 10.2, 23.7) unit (m).

[0056] Start the generator partial discharge online monitoring system, enter the test interface after self-checking, apply a certain voltage to the discharge source model to enable it to discharge stably, and use Figure 2 In the generator partial discharge online monitoring process, the signal source is coupled to four sensors, and after signal conditioning and acquisition, it enters the data concentration processor. After accumulating 50 power frequency cycles of test data, the following is formed: Figure 6 The discharge spectrum shown in Figure 6 (a) to Figure 6 (d) It can clearly show the amount of local discharge tested and the characteristics of the discharge spectrum under the condition of predicted defects; the discharge spectrum is consistent with the internal discharge characteristics of the generator and is determined to be internal discharge of the generator.

[0057] Then start the positioning function of the online monitoring system, such as Figure 4As shown in the figure, the pulse time point coupled to the upper left sensor is obviously ahead of the pulse signals of the other three sensors, so it is preliminarily determined that the discharge source is inside the upper left module of the generator, and then the precise positioning of the discharge source is started. After iterative calculation of the internal positioning algorithm, the final coordinate point approximation is Q (3.15, 9.8, 22.8) units (m), and the error rate with the accurate coordinate position is: x coordinate 1.6%, y coordinate 3.9%, z coordinate 3.8%; it fully meets the positioning requirements.

[0058] It can be seen that the on-line monitoring method for partial discharge of generators based on built-in broadband sensors in this embodiment can accurately test the insulation defects inside the generator, and accurately locate the discharge source through the internal positioning algorithm, with an overall positioning error rate of less than 4%, saving the time for operation and maintenance personnel to find the discharge source and reducing the maintenance cycle. This is of great significance for the normal operation of the generator and the prevention of major breakdown accidents.

Claims

1. A large-scale generator partial discharge online monitoring system, characterized in that: include: Four sensors, a generator body (5), a generator rotor (6), an upper cover (7), a base (8), a water wheel (9), a signal line (10), a transition module (11), a radio frequency cable (12), an analysis module (13), a first data line (14), a central processing module (15), a second data line (16) and a display module (17); the four sensors are sensor A (1), sensor B (2), sensor C (3) and sensor D (4); the upper cover (7) of the generator body (5) is respectively installed with sensor A (1) and sensor D (4); the base (8) of the generator is respectively installed with sensor B (2) and sensor C (3); the generator rotor (6) is located inside the generator body (5); the water wheel (9) is located below the generator body (5); the water wheel (9) is connected to the generator rotor (6); the four signal lines (10) are respectively connected to sensor A (1), sensor B (2), sensor C (3) and sensor D (4); The invention relates to a sensor A (1), a sensor B (2), a sensor C (3) and a sensor D (4), four signal lines (10) connected to a transition module (11), the transition module (11) is then connected to an analysis module (13) through a radio frequency cable (12), the analysis module (13) is then connected to a central processing module (15) through a first data line (14), and the central processing module (15) is connected to a display module (17) through a second data line (16); the analysis module (13) contains a signal frequency selection, detection and amplification processing circuit; the sensor as a whole is in a planar structure and is closely attached to an insulating plate, the insulating plate is respectively fixed on an upper cover (7) and a base (8) of the generator, the output signal line of the sensor is routed along the ground potential of the generator shell, and is led out from a reserved outlet hole and connected to the transition module (11); the transition module (11) contains a wideband matching circuit, and the wideband matching circuit adopts a gradient line and a non-inductive resistor and a capacitor connected in parallel.

2. According to claim 1, the large generator partial discharge online monitoring system is characterized by: Sensor A (1), sensor B (2), sensor C (3) and sensor D (4) are all pre-built into the generator; sensor A (1), sensor B (2), sensor C (3) and sensor D (4) are all unidirectional planar antenna sensors.

3. According to claim 1, the large generator partial discharge online monitoring system is characterized by: The operating frequency band of sensor A (1), sensor B (2), sensor C (3) and sensor D (4) is 100 MHz to 3 GHz, and the standing wave ratio in the frequency band is less than 2.

4. An online monitoring method for the online monitoring system for partial discharge of a large generator as claimed in claim 1, characterized in that: The specific steps include: Step 1, using a sensor to couple the local discharge signal in the generator internal space, and converting it into four-channel broadband local discharge signals, which are then connected to the transition module (11) through a UHF coaxial line, and the controller controls the gain and bandwidth; Step 2: After signal matching, signal filtering and signal amplification, the four-channel broadband partial discharge signals are divided into two channels, and then the two channels are connected to the analysis module (13): After frequency selection, detection and amplification, a low-frequency envelope signal is obtained from one signal. Then, after the low-frequency envelope signal is digitized, the pulse of partial discharge is identified. If it is confirmed that the discharge is generated by the internal discharge source of the generator, the partial discharge signal quantity is divided, the real-time parameters of the partial discharge are calculated and the spectrum of the partial discharge parameters is formed. The spectrum and real-time quantity of the partial discharge parameters are sent to the data concentration processor for analysis, and then stored in the database and displayed. The data concentration processor controls the signal in the conditioning process through the controller according to the analyzed data characteristics. Another signal forms a pulse sequence and enters the pulse sequence synchronization logic; the data concentration processor issues a control command to determine whether to start synchronous acquisition of the pulse sequence: if the control command is yes, the discharge source positioning algorithm is started, the computer software calculates the discharge source position coordinate information, and the discharge source position coordinate information is fed back to the data concentration processor; If the control command is no, then enter the interference source judgment logic.

5. The online monitoring method of the large generator partial discharge online monitoring system according to claim 4 is characterized in that: The specific way in which the controller controls the signal in step 2 is: filter band selection control, amplification gain control, frequency selection control, detection control and low-frequency amplification gain control.

6. A positioning algorithm for the online monitoring system for partial discharge of a large generator as claimed in claim 1, characterized in that: The steps include: Step 1, the generator space is evenly divided into four blocks: upper left, upper right, lower left and lower right. Each block inside the generator contains a sensor; if the signal measured by the sensor is determined to be a partial discharge generated by the discharge source inside the generator, the spatial positioning algorithm is started; the data centralized processing controller starts the synchronous acquisition command; four channels synchronously acquire four-way pulse sequence signals; Step 2: Determine the location of the discharge source using the time delay of the four pulse sequence signals at the same time point. The shorter the time it takes for the pulse sequence signal to reach the corresponding sensor, the more likely the discharge source is located in the block where the sensor that sends the pulse sequence signal is located. The spatial coordinates of the discharge source are calculated using the least squares calculation method and matrix iteration.

7. The positioning algorithm of the large generator partial discharge online monitoring system according to claim 6 is characterized in that: Step 2 specifically includes the following steps: Step 2.

1. Establish a three-dimensional model according to the actual size of the generator body and configure the position coordinate information of the four sensors: treat the generator as a cube model with coordinates, determine the cube coordinates according to the actual size of the generator, and mark the three-dimensional coordinates of the cube, where the source coordinates are Q (x, y, z), and the four sensor coordinates are: upper left sensor Q1 (x1, y1, z1), upper right sensor Q2 (x2, y2, z2), lower left sensor Q3 (x3, y3, z3), and lower right sensor Q4 (x4, y4, z4); Step 2.2, the transmission rate of the discharge electromagnetic wave inside the generator is v; suppose the propagation time of the electromagnetic wave generated by the discharge source to the four sensors is t1, t2, t3, t4 respectively; then the distance equations from the discharge source Q to the sensor Q1, sensor Q2, sensor Q3 and sensor Q4 are: In the above formula, f1(x, y, z, t) is the distance from the discharge source Q to the sensor Q1, f2(x, y, z, t) is the distance from the discharge source Q to the sensor Q2, f3(x, y, z, t) is the distance from the discharge source Q to the sensor Q3, and f4(x, y, z, t) is the distance from the discharge source Q to the sensor Q4; v is the transmission rate of the discharge electromagnetic wave inside the generator; Step 2.3: Let Δt 12 Δt is the time difference between the electromagnetic wave generated by the discharge source reaching the upper right sensor Q2 (x2, y2, z2) and the upper left sensor Q1 (x1, y1, z1); 13 Δt is the time difference between the electromagnetic wave generated by the discharge source reaching the lower left sensor Q3 (x3, y3, z3) and the upper left sensor Q1 (x1, y1, z1); 14 is the time difference between the electromagnetic wave generated by the discharge source reaching the lower right sensor Q4 (x4, y4, z4) and the upper left sensor Q1 (x1, y1, z1), then In the above formula, t2, t3, and t4 are the propagation times of the electromagnetic waves generated by the discharge source to the upper right sensor Q2 (x2, y2, z2), the lower left sensor Q3 (x3, y3, z3), and the lower right sensor Q4 (x4, y4, z4), respectively; where Δt 12 , Δt 13 , Δt 14 Synchronously collect the calculated parameters for the online monitoring system; Introducing vector representation, let: Then, equations (1), (3), (4) and (5) are transformed into: f(x, y, z, t) = 0 (6) Step 2.4: Use the iterative formula (7) to iterate the formula (6) one by one, and obtain the approximate value of the position coordinate Q (x, y, z) parameter as the spatial coordinate position of the discharge source: In the above formula (7): Transform equation (8) and equation (9) into: Among them [A T K A K ] * For [A T K A K ] is the adjoint matrix of .

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