CN107677939A - A kind of localization method of electric power GIS Partial Discharge Sources - Google Patents

Abstract

The invention relates to a method for locating a partial discharge source in a power GIS, comprising the following steps: ①Using a UHF patrol instrument to perform general inspection on the GIS, and initially determining the approximate area of the discharge source according to the detected waveform characteristics and signal strength; ② Use ultra-high frequency positioning method for time difference positioning, determine the smaller discharge area of the discharge source, and further narrow the scope of the area where the discharge source is located; ③Use the ultrasonic positioning method to determine the specific location of the discharge point in the discharge area. The invention combines UHF detection technology and ultrasonic detection technology to jointly locate the discharge source, can quickly and accurately locate the discharge point in the GIS, facilitates early related processing, thereby reducing or avoiding the development of equipment failures, and improving the operation of the GIS reliability.

Description

A Location Method of Partial Discharge Source in Power GIS

technical field

The invention relates to the field of electric power, in particular to a method for locating partial discharge sources of electric power GIS.

Background technique

Sulfur hexafluoride (SF ₆ ) has been widely used in Gas Insulated Switchgear (GIS) at various voltage levels in power systems because of its stable physical and chemical properties, excellent electrical insulation and arc extinguishing properties. Although the reliability of GIS is better than that of open electrical equipment, it will still fail during operation. GIS may cause different degrees of partial discharge due to latent insulation defects in the manufacturing, installation process or long-term operation. Long-term partial discharge will degrade the insulation, resulting in final insulation breakdown and surface flashover and other faults.

The safe operation of GIS is crucial to the stability of the entire power system. Once a fault occurs, it will inevitably cause a power outage in some areas or even the entire area under its jurisdiction. Therefore, it is necessary to discover and deal with GIS defects and hidden dangers as soon as possible through various technical means, reduce or avoid the development of equipment failures, and improve the operational reliability of GIS.

From the perspective of the types of defects that cause failures, insulation defects mainly include: free conductive particles, metal tips, insulator defects and floating potentials. These defects often excite high-frequency electromagnetic waves with a frequency range up to gigahertz. Due to the complex structure and signal attenuation characteristics, there are still many difficulties in quickly and accurately locating the discharge point in GIS.

Contents of the invention

In order to solve the above technical problems, the present invention provides a method for locating the partial discharge source of electric power GIS, which can quickly and accurately locate the discharge point in the GIS, and is convenient for early related processing, thereby reducing or avoiding the development of equipment failure and improving GIS operational reliability.

Above-mentioned technical problem of the present invention is mainly to be solved by following technical scheme: the localization method of power GIS partial discharge source of the present invention, comprises the steps:

①Use the UHF inspection instrument to conduct general survey on GIS, and preliminarily determine the approximate area of the discharge source according to the detected waveform characteristics and signal strength;

② UHF positioning method is used for time difference positioning to determine the smaller discharge area of the discharge source;

③ Determine the specific position of the discharge point in the discharge area by using ultrasonic positioning method.

The invention combines UHF detection technology and ultrasonic detection technology to jointly locate the discharge source, can quickly and accurately locate the discharge point in the GIS, facilitates early related processing, thereby reducing or avoiding the development of equipment failures, and improving the operation of the GIS reliability.

As preferably, the UHF positioning method is as follows: two UHF sensors for monitoring UHF signals are set in the GIS, and a high-speed oscilloscope is used to monitor the UHF signals detected by the two UHF sensors. The waveforms are recorded synchronously, and the smaller discharge area of the discharge source is determined by calculation using the time difference between the two recorded waveforms. Further narrow down the area where the discharge source is located.

As a preference, the specific calculation method of the discharge area is:

Wherein, L is the distance between the two UHF sensors, x is the distance from the discharge source to one of the UHF sensors, and the two UHF sensors monitored by the high-speed oscilloscope are obtained. The time difference of UHF signal waveform is Δt, c is the equivalent propagation velocity of electromagnetic wave in GIS, and the value of c is 3×10 ⁸ m/s.

The ultra-high frequency sensor realizes partial discharge fault detection, avoids the interference of corona discharge in the air, and has high detection efficiency.

As a preference, the ultrasonic positioning method is as follows: laying ultrasonic sensors in the discharge area obtained by the step ②, using the grid method to divide the air chamber housing with a relatively large ultrasonic signal, and for each mesh The grid is used to detect the strength of the discharge ultrasonic signal, and the point of the measured maximum discharge ultrasonic signal strength is positioned as the specific discharge point. The ultrasonic sensor is used for detection, which overcomes the influence of electromagnetic interference, the signal decays quickly, and the discharge point can be accurately located.

As a preference, the two UHF sensors are arranged at both ends of the GIS, the high frequency response characteristics of the two UHF sensors are the same, and the connection signal line between the high-speed oscilloscope and the two UHF sensors The length is also the same.

The beneficial effects of the present invention are: combined with ultra-high frequency detection technology and ultrasonic detection technology to jointly locate the discharge source, the discharge point in the GIS can be quickly and accurately located, and it is convenient for early related processing, thereby reducing or avoiding the development of equipment failure , Improve the operational reliability of GIS.

Description of drawings

Fig. 1 is a schematic diagram of the positional relationship between the UHF sensor and the discharge source in the GIS of the present invention.

Fig. 2 is a schematic diagram of grid division of the grid method in the present invention.

In the figure, 61. UHF sensor, 62. Discharge source, 63. Grid, 64. Isolating switch and grounding switch, 65. Rheology, 66. Pot type insulator, 67. Voltage change, 68. Lightning arrester.

detailed description

The technical solutions of the present invention will be further specifically described below through the embodiments and in conjunction with the accompanying drawings.

Embodiment: A method for locating a power GIS partial discharge source in this embodiment includes the following steps:

① Carry out general survey on GIS with UHF inspection instrument, conduct general survey on basin insulators and built-in UHF sensors in the detection interval or area in GIS, and preliminarily determine the discharge source according to the detected waveform characteristics and signal strength the general area of

② UHF positioning method is used for time difference positioning to determine the smaller discharge area of the discharge source. The UHF positioning method is: two UHF sensors are installed in the GIS to monitor The high-frequency sensors are set at both ends of the GIS. The high-frequency response characteristics of the two UHF sensors are the same. The two UHF sensors are respectively connected to high-speed oscilloscopes. The connecting signal lines between the high-speed oscilloscope and the two UHF sensors The lengths are the same, use a high-speed oscilloscope to record the waveforms of the UHF signals monitored by the two UHF sensors synchronously, and use the time difference between the two recorded waveforms, as shown in Figure 1, to determine the smaller discharge source by calculation Discharge area, the specific calculation method of discharge area is:

Wherein, L is the distance between the two UHF sensors 61, and x is the distance from the discharge source 62 to one of the UHF sensors. The time difference of the high-frequency signal waveform is Δt, c is the equivalent propagation velocity of electromagnetic waves in GIS, and the value of c is 3×10 ⁸ m/s;

③Use the ultrasonic positioning method to determine the specific position of the discharge point in the discharge area. The ultrasonic positioning method is: arrange ultrasonic sensors in the discharge area obtained through step ②, and use the grid method to mesh the air chamber shell with a relatively large ultrasonic signal. Grid division is also carried out on the other side, the upper side and the lower side of the housing. As shown in Figure 2, the middle part of the housing is the isolation switch and the grounding switch 64, and the left side of the housing is the pot insulator 66 and Rheology 65, pot insulator 66 and pressure transformer 67 on the upper side of the shell, pot insulator 66 and lightning arrester 68 on the lower side of the shell, fill in data at each grid 63, and discharge ultrasonic waves on each grid For signal strength detection, the specific location of the discharge point is determined by the graphical representation of the partial discharge ultrasonic signal strength in the grid, and the point where the measured discharge ultrasonic signal strength is maximum is positioned as the specific discharge point.

The invention combines UHF detection technology and ultrasonic detection technology to jointly locate the discharge source, can quickly and accurately locate the discharge point in the GIS, facilitates early related processing, thereby reducing or avoiding the development of equipment failures, and improving the operation of the GIS reliability.

Claims (5)

1. a location method of electric power GIS partial discharge source, is characterized in that comprising the steps: ①Use the UHF inspection instrument to conduct general survey on GIS, and preliminarily determine the approximate area of the discharge source according to the detected waveform characteristics and signal strength; ② UHF positioning method is used for time difference positioning to determine the smaller discharge area of the discharge source; ③ Determine the specific position of the discharge point in the discharge area by using ultrasonic positioning method. 2. The location method of a kind of electric power GIS partial discharge source according to claim 1, it is characterized in that described ultra-high frequency location method is: in GIS, two ultra-high frequency signals are set to monitor UHF The sensor uses a high-speed oscilloscope to simultaneously record the waveforms of the UHF signals monitored by the two UHF sensors, and uses the time difference between the two recorded waveforms to determine the smaller discharge area of the discharge source through calculation. 3. The positioning method of a kind of electric power GIS partial discharge source according to claim 2, is characterized in that the specific calculation method of described discharge area is: Wherein, L is the distance between the two UHF sensors, x is the distance from the discharge source to one of the UHF sensors, and the two UHF sensors monitored by the high-speed oscilloscope are obtained. The time difference of UHF signal waveform is Δt, c is the equivalent propagation velocity of electromagnetic wave in GIS, and the value of c is 3×10 ⁸ m/s. 4. The localization method of a kind of power GIS partial discharge source according to claim 1, it is characterized in that described ultrasonic localization method is: in the discharge region that obtains by described step 2. lay ultrasonic sensor, use grid The method divides the gas chamber shell with a relatively large ultrasonic signal into grids, detects the intensity of the discharge ultrasonic signal for each grid, and locates the point of the maximum intensity of the measured discharge ultrasonic signal as the specific discharge point. 5. according to claim 2 or 3 described a kind of positioning method of electric power GIS partial discharge source, it is characterized in that described two ultra-high frequency sensors are arranged on the two ends of GIS, the high frequency of two ultra high frequency sensors The response characteristics are the same, and the lengths of the connecting signal lines between the high-speed oscilloscope and the two UHF sensors are also the same.