A lightning trip monitoring device and method thereof

Abstract

The present invention discloses a lightning trip monitoring device and method thereof, which are arranged in a transformer substation site, wherein the lightning trip monitoring device comprises an electric field measurement sensor, which is installed at the top of an insulating pole, wherein the insulating pole is vertically connected to the high-altitude high-voltage transmission line in phases and fixedly erected on the ground, and the electric field measurement sensor at the top of the insulating pole is located at a position where the induced electric field strength of the high-voltage transmission line is close to zero potential when the high-voltage transmission line is energized, and the signal of the electric field measurement sensor is introduced into a lightning trip monitoring circuit arranged on the ground through a cable, and the switch monitoring signal of the high-voltage switch monitoring system is connected to the lightning trip monitoring circuit. The present invention collects lightning transient voltage signals in a non-contact manner, and only needs to set up collection devices at the transformer substations at both ends of the transmission line, and does not require power outage for installation and maintenance, thereby realizing synchronous acquisition of lightning transient voltage signals at the time of tripping, and providing accurate information for analysis and judgment of lightning trip types.

Description

Technical Field

[0001] The invention belongs to the technical field of lightning intelligent protection, and in particular relates to a lightning trip monitoring device and a method thereof. Background Art

[0002] The power industry is an important part of the national economy, and transmission lines are the main arteries of the power industry and an important part of the power system. Transmission lines, especially ultra-high and extra-high voltage transmission lines, are long, cover a wide area, have complex natural and geographical conditions, and are easily affected by various natural disasters. The reliability of their operation plays a vital role in the safe and stable operation of the entire power system.

[0003] Lightning damage is one of the most common natural disasters faced by power transmission lines. Lightning strikes have become one of the most important factors leading to power transmission line failures, tripping, and affecting the safe operation of power grids. With the development of ultra-high and extra-high voltage, the problem of lightning protection for transmission lines has become more prominent.

[0004] Lightning tripping has become the main reason for the tripping of transmission lines with voltage levels above 220kV. Although the current lightning location system and the distributed fault monitoring system for transmission lines have been widely used, they can accurately determine whether the line tripping is caused by lightning flashover, and reduce the positioning range of lightning flashover towers to 1-2 bases, but the type of lightning tripping fault cannot be accurately determined. At present, the method for accurately determining the type of lightning tripping is still to first climb the tower to find the discharge channel, calculate the lightning resistance level of the flashover tower, and calculate the shielding tripping rate. The level of intelligence is low and the workload is large. Therefore, it is necessary to analyze the transient voltage signal data monitored to identify the type of lightning fault, so as to improve the efficiency of fault handling and guide the lightning protection measures for transmission lines. In order to accurately determine the type of lightning tripping, it is particularly important to obtain accurate lightning tripping information. However, the current lightning location system and the distributed fault monitoring system for transmission lines usually directly set up transformers along the high-voltage transmission line to obtain lightning signals. Obviously, such facilities cannot provide accurate information for determining the type of lightning tripping. Summary of the invention

[0005] The object of the present invention is to provide a lightning trip monitoring device and method thereof, which adopts a non-contact broadband transient voltage monitoring sensor to collect lightning transient voltage signals and provide accurate information for analyzing and judging the type of lightning tripping.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] A lightning trip monitoring device is arranged in a substation site. There are three-phase A, B, and C high-voltage transmission lines above the substation site. The three-phase high-voltage transmission lines are respectively introduced into the facilities in the substation through knife switches. There is a high-voltage switch monitoring system in the substation. The lightning trip monitoring device includes an electric field measurement sensor, which is installed at the top of an insulating pole. The insulating pole is vertically connected to the high-altitude high-voltage transmission line in phases and fixedly erected on the ground. The electric field measurement sensor at the top of the insulating pole is located at a position where the induced electric field strength of the high-voltage transmission line is close to zero potential when the high-voltage transmission line is energized. The signal of the electric field measurement sensor is introduced into a lightning trip monitoring circuit arranged on the ground through a cable. The switch monitoring signal of the high-voltage switch monitoring system is connected to the lightning trip monitoring circuit.

[0008] A further solution is that the position close to zero potential is a position that enables the electric field measurement sensor to sense a lightning strike signal.

[0009] A further solution is that the insulating upright pole is a telescopic insulating upright pole which is composed of a base tube and a telescopic tube which are sleeved together and can adjust the height.

[0010] The solution is further that a lightning arrester is arranged between the high-voltage transmission line next to the insulating pole and the ground.

[0011] The solution is further that the horizontal distance between the lightning arrester and the insulating pole does not exceed 2.5 meters.

[0012] A further solution is that the electric field measurement sensor is a photoelectric integrated sensor, and the signal of the photoelectric integrated sensor is introduced into a lightning trip monitoring circuit arranged on the ground through an optical fiber cable.

[0013] A monitoring method based on the lightning trip monitoring device comprises the following steps: first, when there is no lightning strike and the high-voltage transmission line is energized, the position of the electric field measurement sensor is adjusted so that the measured electric field strength is between 0 and 100V; wherein, when a lightning strike occurs and an electric field transient change signal is detected from the electric field measurement sensor, the detected electric field transient change waveform information is continuously stored, and the information contains synchronized time information; when a lightning trip occurs, according to the trip time received from the substation high-voltage switch monitoring system, the electric field transient change waveform information of a time period before the trip time is intercepted, and the intercepted electric field transient change waveform information is sent to a lightning trip classification module for type analysis to output the lightning trip type.

[0014] The scheme is further: the lightning trip classification module includes a lightning trip type discrimination convolutional neural network model, which extracts feature information from the intercepted electric field transient change waveform information, sends the extracted feature information to the lightning trip type discrimination convolutional neural network model, and outputs the lightning trip type. The lightning trip type discrimination convolutional neural network model is a model formed by pre-training based on the known lightning trip type and the characteristic image data of the voltage signal of the electric field transient change waveform time period before the lightning tripping type.

[0015] The solution is further that: the time period is a time period in which the electric field transient change waveform information contains multiple electric field intensity absolute values ​​higher than a predetermined peak value.

[0016] A further solution is that the predetermined peak value and quantity are determined based on the electric field transient change waveform information of the known lightning tripping type.

[0017] Compared with the prior art, the beneficial effects of the present invention are: the device collects lightning transient voltage signals in a non-contact manner, and only needs to set up collection devices at the substations at both ends of the transmission line. No power outage is required for installation and maintenance, and the lightning transient voltage signals can be synchronously obtained at the tripping moment, providing accurate information for the analysis and judgment of the lightning tripping type.

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the measuring device of the present invention;

[0020] Figure 2 is a schematic diagram of a measuring circuit of the present invention;

[0021] Figure 3 It is a schematic diagram of the transient change waveform of the electric field captured by the measuring circuit in a time period before the tripping moment. DETAILED DESCRIPTION

[0022] 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.

[0023] In the description of this embodiment, it should be noted that the terms "connect" and "placed" should be understood in a broad sense. For example, "connect" can be a wire connection or a mechanical connection; "placed" can be a fixed connection placement or an integral placement. For ordinary technicians in this field, the specific meanings of the above terms in this embodiment can be understood according to specific circumstances.

[0024] A lightning trip monitoring device is arranged in a substation site, such as Figure 1 and Figure 2 As shown, there are three-phase A, B, and C high-voltage transmission lines 1 above the substation site. The three-phase high-voltage transmission lines are respectively introduced into the facilities in the substation through knife switches 2. There is a high-voltage switch monitoring system 3 in the substation. The high-voltage switch monitoring system 3 monitors the switch state of the high-voltage switch. The lightning trip monitoring device includes an electric field measurement sensor 4, which is installed on the top of an insulating pole 5. The insulating pole is a telescopic insulating pole with adjustable height composed of a base tube 501 and a telescopic tube 502. The insulating pole is vertically connected to the high-altitude high-voltage transmission line and fixedly erected on the ground. The base tube 501 is fixed on a cement base 6 on the ground. The electric field measurement sensor at the top of the insulating pole is located at a position where the induced electric field strength is close to zero potential when the high-voltage transmission line is energized, as shown in FIG. Figure 2 As shown, the signals of the A, B, C three-phase electric field measurement sensors corresponding to the A, B, C three-phase high-voltage transmission lines are introduced into the lightning trip monitoring circuit 7 set on the ground through cables, and the switch monitoring signal of the high-voltage switch monitoring system is connected to the lightning trip monitoring circuit. The lightning trip monitoring circuit 7 can be directly set in the field, or in the monitoring room, and the signals of the electric field measurement sensors are transferred to the lightning trip monitoring circuit in the monitoring room through cables and signal terminal boxes. The monitoring circuit includes a central processing unit and a memory.

[0025] Among them: the position close to zero potential is the position where the electric field measurement sensor can sense the lightning signal, for example: the position where the electric field strength is between 0 and 100V to improve the sensitivity of the sensor measurement, 100V corresponds to a lightning voltage of tens of thousands of volts and can be considered to be close to zero potential.

[0026] For safety, a lightning arrester 8 is arranged between the high-voltage transmission line beside the insulating pole and the ground, wherein: the horizontal distance between the lightning arrester and the insulating pole does not exceed 2.5 meters.

[0027] In this embodiment, the electric field measurement sensor adopts an electrodeless photoelectric integrated sensor. Therefore, the signal of the photoelectric integrated sensor can be introduced into the lightning tripping monitoring circuit set up on the ground through the optical fiber cable. The electrodeless photoelectric integrated sensor has the characteristics of high sensitivity and good anti-interference performance when transmitted through the optical fiber cable.

[0028] The following is a monitoring method based on the above-mentioned lightning tripping monitoring device:

[0029] First, in the absence of lightning strikes and when the high-voltage transmission line is energized, the position of the electric field measurement sensor is adjusted through a retractable insulating pole with an adjustable height so that the measured electric field strength is between 0 and 100V. When a lightning strike occurs, when an electric field transient change signal is detected from the electric field measurement sensor, the detected electric field transient change waveform information is continuously stored, and the information contains synchronized time information. When a lightning trip occurs, according to the trip time received from the substation high-voltage switch monitoring system, the electric field transient change waveform information of the time period before the trip time is intercepted, and the intercepted electric field transient change waveform information is sent to a lightning trip classification module for type analysis to output the lightning trip type. Figure 3 It shows the transient change waveform information of the electric field in a time period before the tripping moment.

[0030] Wherein: the lightning trip classification module includes a lightning trip type discrimination convolutional neural network model, which extracts feature information from the intercepted electric field transient change waveform information, sends the extracted feature information to the lightning trip type discrimination convolutional neural network model, and outputs the lightning trip type. The lightning trip type discrimination convolutional neural network model is a model formed by pre-training based on the known lightning trip type and the characteristic image data of the voltage signal in the electric field transient change waveform time period before the lightning tripping type. The discriminative convolutional neural network model is currently a well-known technology for identifying images, extracting image features, and then inputting the image features into the model for recognition, such as face recognition; the method uses this technology to extract image features from the characteristic image of the voltage signal in the electric field transient change waveform time period before the lightning tripping, and then discriminates the trip type through the discriminative convolutional neural network model.

[0031] The time period is a time period in which the electric field transient change waveform information contains multiple electric field strength absolute values ​​higher than the predetermined peak value, and the predetermined peak value and the number are determined based on the electric field transient change waveform information of the known lightning tripping type. The predetermined peak value is usually selected as 10kv, from Figure 3 It can be seen that the length of the time period is usually around 1.5 milliseconds.

Claims

1. A lightning trip monitoring device is arranged in a substation site. There are three-phase high-voltage transmission lines A, B, and C above the substation site. The three-phase high-voltage transmission lines are respectively introduced into the facilities in the substation through knife switches. There is a high-voltage switch monitoring system in the substation. The lightning trip monitoring device includes an electric field measurement sensor, which is installed at the top of an insulating pole, and is characterized in that: The insulating poles are phase-by-phase perpendicular to the high-altitude high-voltage transmission line and fixedly erected on the ground. The electric field measurement sensor at the top of the insulating pole is located at a position where the induced electric field strength of the high-voltage transmission line is close to zero potential when it is energized. The signal of the electric field measurement sensor is introduced into the lightning trip monitoring circuit set on the ground through a cable. The switch monitoring signal of the high-voltage switch monitoring system is connected to the lightning trip monitoring circuit. The lightning trip monitoring device collects lightning transient voltage signals in a non-contact manner. It only needs to set up collection devices at the substations at both ends of the transmission line. No power outage is required for installation and maintenance. It can synchronously obtain lightning transient voltage signals at the time of tripping, providing accurate information for analysis and judgment of lightning tripping types. in, The position close to zero potential is the position where the electric field measurement sensor can sense the lightning signal; wherein the position where the electric field strength is between 0 and 100V is used to improve the sensitivity of the sensor measurement, and 100V corresponds to a lightning voltage of tens of thousands of volts and is considered to be close to zero potential; The insulating pole is a telescopic insulating pole with adjustable height, which is composed of a base tube and a telescopic tube. From top to bottom, it is: an electric field measuring sensor at the top of the insulating pole, a telescopic tube, and a base tube. A lightning arrester is installed between the three-phase high-voltage transmission lines A, B, and C and the ground respectively, forming a row of three lightning arresters; An insulating pole is installed near each arrester, and a row of three insulating poles is formed; The horizontal distance between the arrester and the insulating pole shall not exceed 2.5 meters; The monitoring method of the lightning tripping monitoring device comprises: First, in the absence of lightning strikes and when the high-voltage transmission line is energized, the position of the electric field measurement sensor is adjusted through a retractable insulating pole with an adjustable height so that the measured electric field strength is between 0 and 100V. When a lightning strike occurs, when an electric field transient change signal is detected from the electric field measurement sensor, the detected electric field transient change waveform information is continuously stored, and the information contains synchronized time information. When a lightning trip occurs, according to the trip time received from the substation high-voltage switch monitoring system, the electric field transient change waveform information of a time period before the trip time is intercepted, and the intercepted electric field transient change waveform information is sent to a lightning trip classification module for type analysis to output the lightning trip type. in: The lightning trip classification module includes a lightning trip type discrimination convolutional neural network model, which extracts feature information from the intercepted electric field transient change waveform information, sends the extracted feature information to the lightning trip type discrimination convolutional neural network model, and outputs the lightning trip type. The lightning trip type discrimination convolutional neural network model is a model formed by pre-training based on known lightning trip types and feature image data of voltage signals in the electric field transient change waveform time period before the lightning trip of the trip type; The time period is a time period in which the electric field transient change waveform information contains multiple electric field intensity absolute values ​​higher than a predetermined peak value; The predetermined peak value and quantity are determined based on known electric field transient change waveform information of lightning tripping type.

2. The lightning trip monitoring device according to claim 1, characterized in that: The electric field measurement sensor is a photoelectric integrated sensor, and the signal of the photoelectric integrated sensor is introduced into a lightning trip monitoring circuit arranged on the ground through an optical fiber cable.

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