Multi-source discharge identification method for GIS partial discharge

Abstract

The invention discloses a multi-source discharge identification method for GIS partial discharge, and the method comprises the steps: firstly, preliminarily judging whether partial discharge occurs through a partial discharge pulse current test of a basin-type insulator, then determining whether a fault occurs again through a photoelectric joint detection test, and identifying a discharge type; a fourth-order Moore fractal antenna is used as a receiving antenna model, the apparent discharge capacity of GIS partial discharge is obtained by combining the antenna receiving and transmitting correlation theory, and finally the discharge position is recognized. According to the method, the pulse current is used as the starting signal of the fault, and then the photoelectric signal is used for secondarily determining whether the fault occurs, so that the diagnosis accuracy is high, and the comprehensive error of GIS discharge point positioning is small.

Description

Technical Field

[0001] The invention belongs to the field of electric power technology, and relates to an electrical technology measurement collection and prediction method, in particular to a GIS diagnosis technology, and specifically to a multi-source discharge identification method for GIS local discharge. Background Art

[0002] The safe and stable operation of the power system is one of the foundations for ensuring the normal operation of modern society. However, in practical applications, electrical equipment often has some faults due to various reasons, such as equipment failure and system paralysis. Among them, partial discharge is a common fault phenomenon in the operation of power equipment. The main reason for its occurrence is defects in the power equipment or external environmental influences. Partial discharge will affect the normal operation of power equipment, and in severe cases may even cause the paralysis of the entire power system. Therefore, real-time monitoring of the partial discharge state of power equipment and timely detection and handling of faults are of great significance to ensure the stable operation of the power system. Gas Insulated Switchgear (GIS) has been widely used in power systems due to its small size, easy installation and high integration. Partial discharge is an important sign and manifestation of GIS insulation degradation, and it is also the key cause of further insulation degradation. The partial discharge signal contains rich insulation status information. Online monitoring of partial discharge can effectively monitor the occurrence and severity of insulation defects. Different types of partial discharges reflect different degradation mechanisms and will cause different degrees of damage to electrical equipment. Therefore, correct diagnosis of partial discharge defects is of great guiding significance for evaluating the internal insulation status of equipment and avoiding the development of insulation degradation.

[0003] After searching the prior art, it was found that Chinese patent application CN117849551A "A method, system, device and medium for locating partial discharge of GIS equipment" builds a digital twin model of GIS equipment, sets a simulated partial discharge power supply in the digital twin model, and builds a partial discharge database based on the discharge of the partial discharge power supply. By comparing the characteristic parameters with the partial discharge database, the interference of external signal sources on the positioning of partial discharge points is reduced, and the accuracy of the positioning of partial discharge points is improved. However, this method only involves the positioning of partial discharge, and does not mention the discharge measurement method and the discharge type identification method.

[0004] Chinese patent application CN117590178A "A device and method for detecting partial discharge of metal particles in GIS" collects multiple current signals through a signal acquisition device to determine whether there is a partial discharge fault caused by metal particles inside the GIS. However, the diagnostic method is limited by the number of partial discharge sources, and the diagnostic accuracy is low in the case of multi-source partial discharge. Summary of the invention

[0005] The technical problem to be solved by the present invention is: in view of the lack of comprehensive detection of GIS partial discharge in the prior art and the limitation of the number of partial discharge sources, a multi-source discharge identification method for GIS partial discharge is provided to comprehensively detect and identify partial discharge of GIS, including discharge type, discharge amount and discharge point positioning, so as to timely discover its internal insulation defects and ensure the safe operation of the equipment.

[0006] The technical solution of the present invention is: a multi-source discharge identification method for GIS local discharge, which uses pulse current as a fault starting signal, measures pulse current and interference pulse current through local discharge pulse current test of basin insulator, and preliminarily determines whether local discharge occurs; then uses photoelectric signal to calculate the average light pulse amplitude, identifies the discharge type through a photoelectric combined detection test method, and obtains the apparent discharge amount of GIS local discharge, and finally locates the breakdown discharge point based on acoustic imaging technology.

[0007] Further, the following steps are included:

[0008] Step a: Establish a test measurement device for partial discharge pulse current of GIS pot insulators and test impedance The output signal is amplified and filtered, i = 1, 2, ..., P, P is the number of pot-type insulators, and the partial discharge pulse current on the ground wire of each insulating component is detected. The pulse current amplitude on the ground wire of each insulating component is synchronously measured using an oscilloscope. and interference pulse current

[0009] Step b: Compare the pulse current amplitudes and interference pulse current like If no partial discharge occurs in the insulator under test, the process returns to step a; otherwise, the process goes to step c;

[0010] Step c: Identify the GIS discharge type through the GIS partial discharge photoelectric joint detection test:

[0011] Conduct GIS partial discharge photoelectric joint detection test and calculate the average optical pulse amplitude

[0012]

[0013] Where Y m is the amplitude of the mth pulse; A is the total number of discharge pulses in M ​​sampling periods;

[0014] like Then the GIS insulation defect type is determined to be particle discharge;

[0015] like Then the GIS insulation defect type is determined to be pinpoint discharge;

[0016] like Then the GIS insulation defect type is determined to be surface discharge;

[0017] like Then the GIS insulation defect type is determined to be suspended discharge;

[0018] Step d: Use Moore fractal antenna to detect GIS partial discharge UHF signal, select the fourth-order Moore fractal antenna as the receiving antenna calculation model, obtain the UHF signal energy w received by the relationship coefficient K, and calculate the apparent discharge amount Q;

[0019] Step e: Use the acoustic imaging sensor based on the sensor array to collect acoustic wave information to locate the GIS discharge point.

[0020] Furthermore, in step d, the calculation method of the apparent discharge amount Q is:

[0021]

[0022] Where R L is the equivalent impedance of the discharge source, Δt represents the sampling time of each point, and n is the number of samples.

[0023] Furthermore, in step e, the GIS discharge point positioning method includes the following steps:

[0024] Step e1: The acoustic sensor array for detecting vibration signals has a total of Z array elements, and the sound signal received by the jth microphone is:

[0025] M j (t) = x j s(t-Δt j )+h j (t)s(t)+b j (t) Formula (3)

[0026] In the formula, Δt j is the time delay from the sound source to the jth microphone position, x j s(t-Δt j ) is the vibration signal from the sound source directly to the microphone, h j (t)s(t) is the reverberation signal, b j (t) is the noise signal;

[0027] Step e2: Calculate the output of the delay-sum beamforming:

[0028]

[0029] Where Δt0 is the propagation delay of the sound to the reference position;

[0030] Step e3: Calculate the controllable response power:

[0031]

[0032] where Y(ω) is the output Fourier transform of the delayed-sum beamforming output y(t), is the complex conjugate of Y(ω);

[0033] Step e4: The controllable response power S is the propagation delay Δt j function, N Δt j Substitute into formula (5) to obtain each possible sound source position vector:

[0034] S(r)=S(r1,r2,r3…r N ) Formula (6)

[0035] Step e5: Determine S(r j ) and the set value S set If S(r j ) is greater than S set , then the jth microphone is the GIS discharge point.

[0036] The present invention first uses pulse current as the fault start signal, then uses the photoelectric signal to confirm whether the fault occurs, identifies the discharge type through the photoelectric combined detection test method, calculates the apparent discharge amount of GIS partial discharge, and finally identifies the discharge location to achieve comprehensive identification and detection of GIS partial discharge. The method of the present invention has the following advantages:

[0037] 1. The method of the present invention first uses pulse current as the starting signal of the fault, and then uses the photoelectric signal to confirm whether the fault occurs, which is free from interference from other factors and has a high diagnostic accuracy.

[0038] 2. The method of the present invention detects the local discharge pulse current on the ground wire of each insulating component, identifies and distinguishes local discharge and interference according to the mutual relationship of the pulse current amplitudes of each insulating component, can effectively eliminate the influence of interference, and can also improve the signal-to-noise ratio and sensitivity of local discharge measurement, and can more sensitively detect tiny local discharge and occasional local discharge of insulating components.

[0039] 3. The method of the present invention utilizes controllable response power to locate GIS breakdown, which has higher positioning accuracy and better noise resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] like Figure 1 As shown, the present invention proposes a multi-source discharge identification method for GIS partial discharge, using pulse current as the starting signal of the fault, and measuring the pulse current and interference pulse current through the partial discharge pulse current test of the basin insulator to preliminarily determine whether partial discharge occurs; then the average optical pulse amplitude is calculated using the photoelectric signal, and the discharge type is identified through the photoelectric combined detection test method, and the apparent discharge amount of GIS partial discharge is obtained, and finally the breakdown discharge point is located based on the acoustic imaging technology. Specifically, it includes the following steps.

[0043] Step a: Establish a mutual reference test measurement device for partial discharge pulse current of GIS pot insulators, which is used to use pulse current as the starting signal of fault and pulse current detection, and to detect the impedance The output signal is amplified and filtered, i = 1, 2, ..., n, n is the number of pot-type insulators, and the partial discharge pulse current on the ground wire of each insulating component is detected. The pulse current amplitude on the ground wire of each insulating component is synchronously measured using an oscilloscope. and interference pulse current

[0044] Step b: Compare the pulse current amplitudes and interference pulse current like It proves that no partial discharge occurs in the insulator under test, and then returns to step a; otherwise, proceed to step c.

[0045] Step c: Identify the GIS discharge type through the GIS partial discharge photoelectric joint detection test.

[0046] Conduct GIS partial discharge photoelectric joint detection test and calculate the average optical pulse amplitude I:

[0047]

[0048] Where Y m is the amplitude of the mth pulse; A is the total number of discharge pulses in M ​​sampling periods;

[0049] like Then the GIS insulation defect type is determined to be particle discharge;

[0050] like Then the GIS insulation defect type is determined to be pinpoint discharge;

[0051] like Then the GIS insulation defect type is determined to be surface discharge;

[0052] like The GIS insulation defect type is determined to be suspended discharge.

[0053] Step d: Use Moore fractal antenna to detect GIS partial discharge UHF signal, select the fourth-order Moore fractal antenna as the receiving antenna calculation model, obtain the UHF signal energy w received by the relationship coefficient K, and calculate the apparent discharge amount Q.

[0054] The calculation method of apparent discharge capacity Q is:

[0055]

[0056] Where R L is the equivalent impedance of the discharge source, Δt represents the sampling time of each point, and n is the number of samples.

[0057] Step e: Use an acoustic imager based on a sensor array to collect acoustic wave information to locate the GIS discharge point.

[0058] The GIS discharge point positioning method includes the following steps:

[0059] Step e1: Locate the GIS discharge point. The acoustic sensor array used to detect the vibration signal has a total of Z array elements. The sound signal received by the jth microphone is:

[0060] M j (t) = x j s(t-Δt j )+h j (t)s(t)+b j (t) Formula (3)

[0061] In the formula, Δt j is the time delay from the sound source to the jth microphone position, x j s(t-Δt j ) is the vibration signal of the sound source directly reaching the jth microphone, h j (t)s(t) is the reverberation signal at the jth microphone, b j (t) is the noise signal of the jth microphone.

[0062] Step e2: Calculate the output of the delay-sum beamforming:

[0063]

[0064] Where Δt0 is the propagation delay of the sound to the reference position.

[0065] Step e3: Calculate the controllable response power:

[0066]

[0067] where Y(ω) is the output Fourier transform of the delayed-sum beamforming output y(t), is the complex conjugate of Y(ω);

[0068] Step e4: The controllable response power S is the propagation delay Δt j function, N Δt j Substitute into formula (5) to obtain each possible sound source position vector:

[0069] S(r)=S(r1,r2,r3…r N ) Formula (6)

[0070] Step e5: Determine S(r j ) and the set value S set If S(r j ) is greater than S set , it is proved that the jth microphone is the GIS discharge point.

Claims

1. A multi-source discharge identification method for GIS partial discharge, characterized by: Using pulse current as the starting signal of the fault, the partial discharge pulse current test of the basin insulator is carried out to measure the pulse current and interference pulse current to preliminarily determine whether partial discharge occurs. Then, the average optical pulse amplitude is calculated using the photoelectric signal, and the discharge type is identified through the photoelectric combined detection test method. The apparent discharge amount of the GIS partial discharge is obtained, and finally the breakdown discharge point is located based on the acoustic imaging technology.

2. The multi-source discharge identification method of GIS partial discharge according to claim 1 is characterized by: The following steps are involved: Step a: Establish a test measurement device for partial discharge pulse current of GIS pot insulators and test impedance The output signal is amplified and filtered, i = 1, 2, ..., P, P is the number of pot-type insulators, and the partial discharge pulse current on the ground wire of each insulating component is detected. The pulse current amplitude on the ground wire of each insulating component is synchronously measured using an oscilloscope. and interference pulse current Step b: Compare the pulse current amplitudes and interference pulse current like If no partial discharge occurs in the insulator under test, the process returns to step a; otherwise, the process goes to step c; Step c: Identify the GIS discharge type through the GIS partial discharge photoelectric joint detection test: Conduct GIS partial discharge photoelectric joint detection test and calculate the average optical pulse amplitude Where Y m is the amplitude of the mth pulse; A is the total number of discharge pulses in M ​​sampling periods; like Then the GIS insulation defect type is determined to be particle discharge; like Then the GIS insulation defect type is determined to be pinpoint discharge; like Then the GIS insulation defect type is determined to be surface discharge; like Then the GIS insulation defect type is determined to be suspended discharge; Step d: Use Moore fractal antenna to detect GIS partial discharge UHF signal, select the fourth-order Moore fractal antenna as the receiving antenna calculation model, obtain the UHF signal energy w received by the relationship coefficient K, and calculate the apparent discharge amount Q; Step e: Use the acoustic imaging sensor based on the sensor array to collect acoustic wave information to locate the GIS discharge point.

3. The multi-source discharge identification method of GIS partial discharge according to claim 2 is characterized in that in step d, the calculation method of the apparent discharge amount Q is: Where R L is the equivalent impedance of the discharge source, Δt represents the sampling time of each point, and n is the number of samples.

4. The multi-source discharge identification method of GIS partial discharge according to claim 2 is characterized by: In step e, the GIS discharge point positioning method comprises the following steps: Step e1: The acoustic sensor array for detecting vibration signals has a total of Z array elements, and the sound signal received by the jth microphone is: M j x(t) = x j s(t - Δt j ) + h j (t)s(t) + b j (t), Equation (3) In the formula, Δt j is the time delay from the sound source to the jth microphone position, x j s(t-Δt j ) is the vibration signal from the sound source directly to the microphone, h j (t)s(t) is the reverberation signal, b j (t) is the noise signal; Step e2: Calculate the output of the delay-sum beamforming: Where Δt0 is the propagation delay of the sound to the reference position; Step e3: Calculate the controllable response power: where Y(ω) is the output Fourier transform of the delayed-sum beamforming output y(t), is the complex conjugate of Y(ω); Step e4: The controllable response power S is the propagation delay Δt j function, N Δt j Substitute into formula (5) to obtain each possible sound source position vector: S(r)=S(r1,r2,r3…r N ) Formula (6) Step e5: Determine S(r j ) and the set value S set If S(r j ) is greater than S set , then the jth microphone is the GIS discharge point.

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