Primary equipment abnormity monitoring method based on broadband transient voltage and current

Abstract

The invention relates to the technical field of primary equipment abnormity monitoring in a power transmission line, and discloses a parallel primary equipment abnormity monitoring method based on broadband transient voltage and current, and the method comprises the steps: configuring a broadband transient voltage measurement device capable of measuring transient voltage in a line where primary equipment is located; a non-contact broadband current measuring device used for measuring the grounding current waveform of the primary equipment is arranged on a grounding wire of the primary equipment; equivalently converting the primary equipment into a T-shaped broadband equivalent model; calculating a theoretical primary side grounding current according to the primary side transient voltage of the T-type broadband equivalent model; and comparing the theoretical primary side grounding current with the actual primary side grounding current of the T-type broadband equivalent model detected by the non-contact broadband current measurement device, and judging whether the primary equipment is abnormal or not according to a comparison result. The operation condition of the primary equipment can be monitored in real time.

Description

Technical Field

[0001] The present invention relates to the technical field of primary equipment abnormality monitoring in a power transmission line, and in particular to a primary equipment abnormality monitoring method based on broadband transient voltage and current. Background Art

[0002] At present, a large number of primary equipment in the power system, except for core equipment such as transformers, are equipped with expensive online monitoring devices. A large number of primary equipment, such as reactors, capacitors, and mutual inductors, are not equipped with corresponding online monitoring devices. If a local fault or defect occurs inside the equipment, it is difficult to detect and deal with it in time. As it develops, it may cause accidents in power operation. It is too costly to widely use online monitoring devices for core equipment for all primary equipment. Therefore, how to design a widespread and low-cost abnormal monitoring method for primary equipment is an issue that needs to be considered urgently. Summary of the invention

[0003] The present invention is based on the measurement technology of broadband transient voltage and current waveforms, and provides a primary equipment abnormality monitoring method based on broadband transient voltage and current, which can realize online abnormality perception of widely parallel primary equipment.

[0004] The present invention is achieved through the following technical solutions:

[0005] A method for monitoring primary equipment abnormality based on broadband transient voltage and current, comprising:

[0006] A broadband transient voltage measuring device capable of measuring transient voltage is configured on the high-voltage side line where the primary equipment is located;

[0007] A non-contact wide-band current measuring device for measuring a ground current waveform of the primary device is provided on the grounding wire of the primary device;

[0008] Converting the primary equipment into a T-type broadband equivalent model;

[0009] Calculating the theoretical primary side grounding current of the T-type broadband equivalent model according to the primary side transient voltage of the T-type broadband equivalent model measured by the broadband transient voltage measuring device;

[0010] The theoretical primary side grounding current is compared with the actual primary side grounding current of the T-type broadband equivalent model detected by the non-contact broadband current measuring device, and whether the primary device is abnormal is determined according to the comparison result.

[0011] As an optimization, the broadband transient voltage measuring device and the non-contact broadband current measuring device are both electrically connected to a computer.

[0012] As an optimization, the primary device is connected between a primary high-voltage line and the ground; if there are multiple primary devices, the multiple primary devices are arranged in parallel, and the wide-band transient voltage measuring device is arranged on a common primary high-voltage line where the multiple primary devices are arranged in parallel.

[0013] As an optimization, the non-contact broadband current measuring device is arranged in a one-to-one correspondence with the primary equipment.

[0014] As an optimization, the specific process of converting the primary equipment into a T-type broadband equivalent model is as follows:

[0015] A1. Let the end of the primary device connected to the line be the primary end, and the end connected to the ground be the grounding end. The area between the primary end and the ground is port one, and the area between the grounding end and the ground is port two.

[0016] A2. Measure the scattering parameters S of the port 1 and the port 2 in the set frequency band by using a network analyzer. 11 , S 12 , S 21 and S 22 ; Among them, S 11 is the reflection parameter of port 1, S 12 is the transfer parameter from port 1 to port 2, S 22 is the reflection parameter of port 2, S 21 is the transfer parameter from port 2 to port 1;

[0017] A3, the scattering parameter S 11 , S 12 , S 21 and S 22 Converted into two-port impedance parameter Z 11 , Z 12 , Z 21 and Z 22 ;

[0018] A4. The dual-port impedance parameter Z 11 , Z 12 , Z 21 and Z 22 Converted into three single-port impedance parameters Z A , Z B , Z C , three single-port modules form a T-shaped structure;

[0019] A5. Impedance parameters Z based on three single-port modules A , Z B , Z C Correspondingly, equivalent circuits of the three single-port modules are constructed to obtain a T-type broadband equivalent model of the primary device.

[0020] As an optimization, the two-port impedance parameter Z 11 , Z 12 , Z 21 and Z 22 The specific formula is:

[0021]

[0022] in, Among them, Z o is the characteristic impedance, take 50Ω;

[0023] Impedance parameters Z of three one-port modules A , Z B , Z C The specific formula is:

[0024] Z A =Z 11 -Z 12 ;

[0025]

[0026] Z C =Z 22 -Z 12 .

[0027] As an optimization, the impedance parameters Z of the three single-port modules are respectively A , Z B , Z C The specific process of constructing the equivalent circuits of the three single-port modules is as follows:

[0028] A5.1. The impedance parameters Z of the three single-port modules are A , Z B , Z C Mathematical fitting is performed within the measurement bandwidth to fit into rational expressions of residue and pole types: Where * represents complex conjugate, P ri and ri represent the ith real pole and residue respectively, P ci , P ci *、r ci and r ci * represents the i-th pair of complex conjugate poles and residues, h is a constant term, and s is the Laplace operator;

[0029] A5.2. Equivalently convert the constant term, real pole, and complex conjugate pole into a constant branch G, a real pole branch GC, and a conjugate pole branch circuit GCLR;

[0030] A5.3. Connect the constant branch G, the real pole branch GC and the conjugate pole branch circuit GCLR corresponding to the impedance parameters of each single-port module in series to finally obtain a T-type broadband equivalent model.

[0031] As an optimization, the constant branch G includes a resistor, and the resistance on the constant branch G is G0, G0=1 / h;

[0032] The real pole branch GC includes a resistor and a capacitor connected in parallel. Let the capacitor in the real pole branch GC be C i , the resistance is G i ,

[0033] The conjugate pole branch circuit GCLR is composed of a series branch consisting of a resistor and an inductor in series and a parallel branch consisting of a resistor and a capacitor in parallel. The capacitance in the parallel branch is The resistance is Let the inductance in the series branch be The resistance is

[0034] As an optimization, a specific method for calculating the theoretical primary side grounding current of the T-type broadband equivalent model according to the primary side transient voltage of the T-type broadband equivalent model measured by the broadband transient voltage measuring device includes:

[0035] The T-type broadband equivalent model is set in the simulation software, and the number and size of the capacitors, resistors, and inductors in the T-type broadband equivalent model are set. Then, the primary side transient voltage is input into the simulation software to obtain the theoretical primary side grounding current of the T-type broadband equivalent model.

[0036] As an optimization, a specific method for calculating the theoretical primary side grounding current of the T-type broadband equivalent model according to the primary side transient voltage of the T-type broadband equivalent model measured by the broadband transient voltage measuring device includes:

[0037] Each capacitor and inductor in the T-type broadband equivalent model is equivalently converted into an inductor equivalent model and a capacitor equivalent model consisting of a parallel conductance and an ideal current source, so that the T-type broadband equivalent model is composed of a resistor, a conductance and an ideal current source;

[0038] Calculate the conductance g in the inductor equivalent model and the capacitor equivalent model respectively. L , g c , g L is the first conductance value in the inductor equivalent model, g cis the second conductance value in the capacitor equivalent model, L and C are the inductance value in the inductance equivalent model and the capacitance value in the capacitance equivalent model, respectively, and △t is the calculation step time;

[0039] Calculate the ideal current source I in the inductor equivalent model and the capacitor equivalent model respectively. 电流源 , I′ 电流源 The size of I 电流源 , I′ 电流源 are the ideal current sources in the inductor equivalent model and the capacitor equivalent model respectively, Among them, i k-1 、u k-1 are the current values ​​of the previous calculation step in the inductor equivalent model, i′ k-1 , u′ k-1 are respectively the current values ​​of the last calculation step in the capacitor equivalent model;

[0040] The equations corresponding to the circuit matrix formed by the resistance, conductance and ideal current source in the T-type broadband equivalent model are listed, and the primary-side transient voltage as the input voltage of the T-type broadband equivalent model is regarded as a known quantity, and the theoretical primary-side grounding current at the output end of the T-type broadband equivalent model is calculated.

[0041] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0042] The present invention designs a widespread and low-cost method for abnormal monitoring of primary equipment, which can monitor the operation of the primary equipment in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0044] Figure 1 A schematic diagram of the hardware configuration structure for implementing a primary equipment abnormality monitoring method based on broadband transient voltage and current of the present invention;

[0045] Figure 2 It is a schematic diagram of dual ports of a primary device;

[0046] Figure 3 It is a structural diagram of the initial T-type equivalent broadband model;

[0047] Figure 4 It is the structural diagram of the constant branch;

[0048] Figure 5 It is a structural diagram of the real pole branch;

[0049] Figure 6 Schematic diagram of the structure of the conjugate pole branch;

[0050] Figure 7 It is a structural schematic diagram of a T-type broadband equivalent model of a primary device;

[0051] Figure 8 It is a structural diagram of the equivalent model of inductance or capacitance. DETAILED DESCRIPTION

[0052] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0053] This embodiment 1 provides a primary equipment abnormality monitoring method based on broadband transient voltage and current, including:

[0054] A wide-band transient voltage measuring device capable of accurately measuring transient voltage is configured on the high-voltage side line where the primary device is located; in some embodiments, if there are multiple primary devices, the multiple primary devices are arranged in parallel, and the wide-band transient voltage measuring device is arranged on the common line where the multiple primary devices are arranged in parallel.

[0055] Wideband transient voltage measurement itself is a device of many types. The present invention is not limited to the use of any type, as long as it can achieve "accurate measurement of wideband transient voltage waveform of high-voltage line" power supply.

[0056] This is the first step. For the line or bus where the parallel equipment (hereinafter referred to as "primary equipment") that needs to realize online abnormality perception is located, a broadband transient voltage measuring device is configured. The device should meet two requirements: 1. The broadband transient voltage measuring device should be able to accurately measure the standard lightning impulse voltage waveform (transient voltage); 2. The broadband transient voltage measuring device and one or more primary equipment should be on the same bus or line under rated conditions. Therefore, when a transient voltage occurs on the line or bus, it can trigger the broadband transient voltage measuring device to measure the transient voltage waveform acting on the primary end of the primary equipment.

[0057] A non-contact broadband current measuring device for measuring the ground current waveform of the primary device is provided on the ground line of the primary device; in some embodiments, the non-contact broadband current measuring device is provided in a one-to-one correspondence with the primary device.

[0058] This is the second step, to install a non-contact broadband current measuring device on the grounding wire of each primary device. The device can be a Rogowski coil or a Hall coil, which can accurately measure the grounding current waveform of the primary device. Figure 1 As shown, in the parallel primary equipment on the line or bus equipped with a broadband transient voltage measuring device, it is necessary to equip its (primary equipment) grounding wire with a non-contact broadband current measuring device if the abnormality detection method proposed in the present invention is applied. For example, a broadband current measuring device is installed on the grounding wire of the parallel capacitor to realize online monitoring of the parallel capacitor, and another example is to install a broadband current measuring device on the grounding wire of the bushing end screen to realize online monitoring of the bushing.

[0059] In some embodiments, the broadband transient voltage measuring device and the non-contact broadband current measuring device are both electrically connected to a computer.

[0060] The output digital signal of the broadband transient voltage measuring device on the line or bus and the output digital signal of the broadband current measuring device on the primary equipment grounding wire are both connected to the computer. At the same time, the broadband current measuring device on the primary equipment grounding wire is synchronously triggered by the broadband transient voltage measuring device on the line or bus. At this point, the hardware preparation is completed.

[0061] Converting the primary equipment into a T-type broadband equivalent model;

[0062] Calculating the theoretical primary side grounding current of the T-type broadband equivalent model according to the primary side transient voltage of the T-type broadband equivalent model measured by the broadband transient voltage measuring device;

[0063] This is the third step, which is to establish a "wideband model of primary input voltage-ground current" (i.e., T-type broadband equivalent model) of the primary equipment in a healthy state, and to establish the calculation method of the model.

[0064] In some embodiments, the specific process of converting the primary device into a T-type broadband equivalent model is as follows:

[0065] A1. Let the end of the primary device connected to the line be the primary end, and the end connected to the ground be the grounding end. The area between the primary end and the ground is port one, and the area between the grounding end and the ground is port two.

[0066] A2. Measure the scattering parameters S of the port 1 and the port 2 within the set frequency band by means of a network analyzer. 11 , S 12 , S 21 and S 22 ;

[0067] One method that can be used in the present invention is to establish a broadband model based on a network analyzer. Specifically, the primary and ground leads of a primary device in a healthy state are untied, such as Figure 2 As shown in the figure, the area between the primary terminal and the ground is taken as port 1, and the area between the ground terminal and the ground is taken as port 2. The scattering parameters S of the two ports of the primary device within the set frequency band are measured using a network analyzer. 11 , S 12 ,S 21 and S 22 . S 11 is the reflection parameter of port 1, S 12 is the transfer parameter from port 1 to port 2, S 22 is the reflection parameter of port 2, S 21 is the transfer parameter from port 2 to port 1. After the measurement is completed, the wiring of the primary device should be restored. A3. 11 , S 12 , S 21 and S 22 Converted into two-port impedance parameter Z 11 , Z 12 , Z 21 and Z 22 ;

[0068] After the measurement is completed and the two-port scattering parameters are obtained, they are converted into two-port impedance parameters (Z parameters, including Z 11 , Z 12 , Z 21 and Z 22 ).

[0069]

[0070] A4. The dual-port impedance parameter Z 11 , Z 12 , Z 21 and Z 22 Converted into three single-port impedance parameters Z A , Z B , Z C , three single-port modules form a T-shaped structure; among them, Z o is the characteristic impedance, take 50Ω;

[0071] The two-port impedance parameters are then converted into three single-port impedance parameters through the following calculations. The impedance parameters of the three single-port models represent the three single-port modules Z A ,Z B and Z C like Figure 3 A T-type connection is shown, which is the initial equivalent broadband model of the primary equipment.

[0072] Z A =Z 11 -Z 12 ;

[0073]

[0074] Z C =Z 22 -Z 12 ; (9)

[0075] A5. Impedance parameters Z based on three single-port modules A , Z B , Z C Correspondingly, equivalent circuits of the three single-port modules are constructed to obtain a T-type broadband equivalent model of the primary device.

[0076] In some embodiments, the specific process of A5 is:

[0077] A5.1. The impedance parameters Z of the three single-port modules are A , Z B , Z C Mathematical fitting is performed within the measurement bandwidth to fit into rational expressions of residue and pole types:

[0078] Where * represents complex conjugate, P ri and ri represent the ith real pole and residue respectively, P ci , P ci *、r ci and r ci * represents the i-th pair of complex conjugate poles and residues, h is a constant term, and s is the Laplace operator;

[0079] Z A , Z B , Z C It is discrete data within the frequency band, and the above mathematical formula is fitted. The curve drawn by this formula in the coordinate system can fit the discrete data points of ZA, ZB and ZC distributed in the frequency band.

[0080] This step is to construct an equivalent circuit for the three one-port modules.

[0081] First, the impedance parameters of the three single-port modules are mathematically fitted within the measurement bandwidth to fit into rational expressions in the form of residues and poles. One method that can be used is to use the vector matching method to fit the rational expression shown in equation (10).

[0082] A5.2. Equivalently convert the constant term, real pole, and complex conjugate pole into a constant branch G, a real pole branch GC, and a conjugate pole branch circuit GCLR;

[0083] For the constant term h, it is equivalent to Figure 4 The G0 resistance branch shown, that is, the constant branch G includes a resistor. The resistance on the constant branch G is G0, referred to as G branch, and the resistance value is 1 / h.

[0084] The number of complex poles and real poles is not fixed, and is determined in detail during the fitting process based on the results of the fitting. Generally, the more the number, the more accurate it is, but the subsequent calculation amount is greater, so the number is determined according to the actual situation during each fitting process.

[0085] For real term poles, this is equivalent to Figure 5 The resistor and capacitor are connected in parallel, referred to as the GC branch, and the component values ​​are calculated as shown in equations (11) and (12).

[0086] That is, the real pole branch GC includes a resistor and a capacitor connected in parallel. Let the capacitance in the real pole branch GC be C i , the resistance is G i ,

[0087] For the complex conjugate pole term, it can be synthesized into a Figure 6 G shown i C i L i R i The series-parallel form is referred to as the GCLR branch, and the component values ​​are calculated as shown in equations (13) to (16).

[0088] That is, the conjugate pole branch circuit GCLR is composed of a series branch consisting of a resistor and an inductor in series and a parallel branch consisting of a resistor and a capacitor in parallel. Let the capacitance in the parallel branch be The resistance is Let the inductance in the series branch be The resistance is

[0089] A5.3. Connect the constant branch G, the real pole branch GC and the conjugate pole branch circuit GCLR corresponding to the impedance parameters of each single-port module in series to finally obtain a T-type broadband equivalent model.

[0090] By connecting the above branches in series, the equivalent circuit of each single-port module can be formed. Figure 3 The T-type circuit shown in the figure is connected, and the entire T-type circuit is as follows Figure 7 As shown in the figure, the broadband equivalent model of the primary equipment is established.

[0091] The calculation method of the model is:

[0092] Figure 7 Middle,U in The transient voltage waveform of the primary terminal of the primary device measured by the broadband transient voltage measuring device, I g It is the ground current waveform responded on the ground wire of the primary equipment.

[0093] In some embodiments, the T-type broadband equivalent model is set in simulation software (any common tool that can perform electromagnetic calculations, such as MATLAB, Python, C language, etc.), and the number and size of capacitors, resistors, and inductors in the T-type broadband equivalent model are set. Then, the primary side transient voltage is input into the simulation software to obtain the theoretical primary side grounding current of the T-type broadband equivalent model.

[0094] According to U in The theoretical response ground current waveform can be calculated directly in the simulation software. Figure 7 The model shown is used to measure the U in As the excitation signal, the simulation software can be used to simulate and calculate the theoretical response waveform I g-理论 (Theoretical primary ground current).

[0095] In some embodiments, when simulation software is not available, the theoretical I can also be calculated by numerical calculation. g waveform. One possible method is to first Figure 7 In the model shown, each capacitor and inductor is Figure 8 Perform equivalent conversion.

[0096] In each step of the calculation, the inductor and the linear capacitor can be equivalent to a conductance and an ideal current source in parallel, that is, each capacitor and inductor in the T-type broadband equivalent model is equivalently converted into an inductance equivalent model and a capacitance equivalent model composed of a parallel conductance and an ideal current source, so that the T-type broadband equivalent model is composed of a resistor, a conductance and an ideal current source;

[0097] Calculate the conductance g in the inductor equivalent model and the capacitor equivalent model respectively. L , g c , g L is the first conductance value in the inductor equivalent model, g c is the second conductance value in the capacitor equivalent model, L and C are the inductance value in the inductance equivalent model and the capacitance value in the capacitance equivalent model, respectively, and △t is the calculation step time;

[0098] Calculate the ideal current source I in the inductor equivalent model and the capacitor equivalent model respectively. 电流源 , I′ 电流源 The size of I 电流源 , I′ 电流源 are the ideal current sources in the inductor equivalent model and the capacitor equivalent model respectively, Among them, i k-1 、u k-1 are the current values ​​of the last calculation step (the time between every two data sampling points) in the inductor equivalent model, i′ k-1 , u′ k-1 are respectively the current values ​​of the previous calculation step in the capacitor equivalent model; in the equivalent models of inductance and capacitance, the current value of the ideal current source is related to the previous step, and for the first step of calculation, the current value of the ideal current source is 0.

[0099] The equations corresponding to the circuit matrix formed by the resistance, conductance and ideal current source in the T-type broadband equivalent model are listed, and the primary-side transient voltage as the input voltage of the T-type broadband equivalent model is regarded as a known quantity, and the theoretical primary-side grounding current at the output end of the T-type broadband equivalent model is calculated.

[0100] The theoretical primary side grounding current is compared with the actual primary side grounding current of the T-type broadband equivalent model detected by the non-contact broadband current measuring device, and whether the primary device is abnormal is determined according to the comparison result.

[0101] This is the fourth and final step, which is comparison. Every time the broadband transient voltage measuring device is triggered to measure the transient voltage waveform U in After that, the current measuring device at the secondary end of the primary device will give the actual response current waveform I g-测量 At the same time, simulation software or numerical calculation method is used on the computer according to U in Calculate the theoretical response waveform I g-理论 .

[0102] Will I g-测量 and I g-理论 Compare the two waveforms to judge the similarity of the waveforms. Any method that can quantitatively evaluate the similarity of the two curves can be used, and a warning threshold value is set. When the similarity is lower than the warning threshold value, it indicates that the primary equipment may be abnormal, and an early warning message is sent to the equipment operation and maintenance department.

[0103] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for monitoring primary equipment abnormality based on broadband transient voltage and current, characterized in that: include: A broadband transient voltage measuring device capable of measuring transient voltage is configured on the high-voltage side line where the primary equipment is located; A non-contact wide-band current measuring device for measuring a ground current waveform of the primary device is provided on the grounding wire of the primary device; Converting the primary equipment into a T-type broadband equivalent model; Calculating the theoretical primary side grounding current of the T-type broadband equivalent model according to the primary side transient voltage of the T-type broadband equivalent model measured by the broadband transient voltage measuring device; The theoretical primary side grounding current is compared with the actual primary side grounding current of the T-type broadband equivalent model detected by the non-contact broadband current measuring device, and whether the primary device is abnormal is determined according to the comparison result.

2. A method for monitoring primary equipment abnormality based on broadband transient voltage and current according to claim 1, characterized in that: The broadband transient voltage measuring device and the non-contact broadband current measuring device are both connected to a computer.

3. The method for monitoring primary equipment abnormality based on broadband transient voltage and current according to claim 1, characterized in that: The primary device is connected between a primary high-voltage line and the ground; if there are multiple primary devices, the multiple primary devices are arranged in parallel, and the broadband transient voltage measuring device is arranged on a common primary high-voltage line where the multiple primary devices are arranged in parallel.

4. The method for monitoring primary equipment abnormality based on broadband transient voltage and current according to claim 1, characterized in that: The non-contact broadband current measuring device is arranged in one-to-one correspondence with the primary equipment.

5. The method for monitoring primary equipment abnormality based on broadband transient voltage and current according to claim 1, characterized in that: The specific process of converting the primary equipment into a T-type broadband equivalent model is as follows: A1. Let the end of the primary device connected to the line be the primary end, and the end connected to the ground be the grounding end. The area between the primary end and the ground is port one, and the area between the grounding end and the ground is port two. A2. Measure the scattering parameters S of the port 1 and the port 2 in the set frequency band by using a network analyzer. 11 , S 12 , S 21 and S 22 ; Among them, S 11 is the reflection parameter of port 1, S 12 is the transfer parameter from port 1 to port 2, S 22 is the reflection parameter of port 2, S 21 is the transfer parameter from port 2 to port 1; A3, the scattering parameter S 11 , S 12 , S 21 and S 22 Converted into two-port impedance parameter Z 11 , Z 12 , Z 21 and Z 22 ; A4. The dual-port impedance parameter Z 11 , Z 12 , Z 21 and Z 22 Converted into three single-port impedance parameters Z A , Z B , Z C , three single-port modules form a T-shaped structure; A5. Impedance parameters Z based on three single-port modules A , Z B , Z C Correspondingly, equivalent circuits of the three single-port modules are constructed to obtain a T-type broadband equivalent model of the primary device.

6. A method for monitoring primary equipment abnormality based on broadband transient voltage and current according to claim 5, characterized in that: The two-port impedance parameter Z 11 , Z 12 , Z 21 and Z 22 The specific formula is: in, Among them, Z o is the characteristic impedance; Impedance parameters Z of three one-port modules A , Z B , Z C The specific formula is: WITH A =Z 11 -WITH 12 ; WITH C =Z 22 -WITH 12 。 7. A method for monitoring primary equipment abnormality based on broadband transient voltage and current according to claim 6, characterized in that: Based on the impedance parameters Z of the three single-port modules A , Z B , Z C The specific process of constructing the equivalent circuits of the three single-port modules is as follows: A5.

1. The impedance parameters Z of the three single-port modules are A , Z B , Z C Mathematical fitting is performed within the measurement bandwidth to fit into rational expressions of residue and pole types: Where * represents complex conjugate, P ri and ri represent the ith real pole and residue respectively, P ci , P ci *、r ci and r ci * represents the i-th pair of complex conjugate poles and residues, h is a constant term, and s is the Laplace operator; A5.

2. Equivalently convert the constant term, real pole, and complex conjugate pole into a constant branch G, a real pole branch GC, and a conjugate pole branch circuit GCLR; A5.

3. Connect the constant branch G, the real pole branch GC and the conjugate pole branch circuit GCLR corresponding to the impedance parameters of each single-port module in series to finally obtain a T-type broadband equivalent model.

8. A method for monitoring primary equipment abnormality based on broadband transient voltage and current according to claim 7, characterized in that: The constant branch G includes a resistor, and the resistance of the constant branch G is G0, G0=1 / h; The real pole branch GC includes a resistor and a capacitor connected in parallel. Let the capacitor in the real pole branch GC be C i , the resistance is G i , The conjugate pole branch circuit GCLR is composed of a series branch consisting of a resistor and an inductor in series and a parallel branch consisting of a resistor and a capacitor in parallel. The capacitance in the parallel branch is The resistance is Let the inductance in the series branch be The resistance is 9. The method for monitoring primary equipment abnormality based on broadband transient voltage and current according to claim 1, characterized in that: The specific method for calculating the theoretical primary side grounding current of the T-type broadband equivalent model according to the primary side transient voltage of the T-type broadband equivalent model measured by the broadband transient voltage measuring device includes: The T-type broadband equivalent model is set in the simulation software, and the number and size of the capacitors, resistors, and inductors in the T-type broadband equivalent model are set. Then, the primary side transient voltage is input into the simulation software to obtain the theoretical primary side grounding current of the T-type broadband equivalent model.

10. A method for monitoring primary equipment abnormality based on broadband transient voltage and current according to claim 8, characterized in that: The specific method for calculating the theoretical primary side grounding current of the T-type broadband equivalent model according to the primary side transient voltage of the T-type broadband equivalent model measured by the broadband transient voltage measuring device includes: Each capacitor and inductor in the T-type broadband equivalent model is equivalently converted into an inductor equivalent model and a capacitor equivalent model consisting of a parallel conductance and an ideal current source, so that the T-type broadband equivalent model is composed of a resistor, a conductance and an ideal current source; Calculate the conductance g in the inductor equivalent model and the capacitor equivalent model respectively. L , g c , g L is the first conductance value in the inductor equivalent model, g c is the second conductance value in the capacitor equivalent model, L and C are the inductance value in the inductance equivalent model and the capacitance value in the capacitance equivalent model, respectively, and △t is the calculation step time; Calculate the ideal current source I in the inductor equivalent model and the capacitor equivalent model respectively. 电流源 , I′ 电流源 The size of I 电流源 , I′ 电流源 are the ideal current sources in the inductor equivalent model and the capacitor equivalent model respectively, Among them, i k-1 、u k-1 are the current values ​​of the previous calculation step in the inductor equivalent model, i′ k-1 , u′ k-1 are respectively the current values ​​of the last calculation step in the capacitor equivalent model; The equations corresponding to the circuit matrix formed by the resistance, conductance and ideal current source in the T-type broadband equivalent model are listed, and the primary-side transient voltage as the input voltage of the T-type broadband equivalent model is regarded as a known quantity, and the theoretical primary-side grounding current at the output end of the T-type broadband equivalent model is calculated.

Images