Method for measuring impact earthing impedance of electric transmission overhead line structure earthing device with lightning conductor

Abstract

The invention provides a method for measuring impact earthing impedance of an electric transmission overhead line structure earthing device with a lightning conductor. According to the method, a lightning conductor or an overhead ground wire of other type are erected on an electric transmission overhead line structure; the earthing device of the overhead line structure is connected with the overhead line structure or the lightning conductor or the overhead ground wire through a downlead; the downlead is connected with the earthing device through bolts; the downlead and the earthing device are electrically connected and can be detached. According to the method, the impact earthing impedance of the electric transmission overhead line structure earthing electrode can be directly measured, errors in measurement caused by uneven soil structure and measuring electrode position deviation are avoided, the wiring manner is simpler and the measurement result is more accurate; through the adoption of the methods such as increasing the amplitude value of the output voltage waveform or the current waveform of the power supply or multiplying spark discharging coefficient, the impact earthing impedance of the electric transmission overhead line structure earthing device after the spark discharge can be further gained.

Description

technical field [0001] The invention relates to a method for measuring the impact grounding impedance of a transmission line pole tower grounding device with lightning protection wires or other types of overhead ground wires. The method is suitable for lightning protection design and lightning protection transformation of transmission line pole towers, and belongs to the field of power system overvoltage testing. Background technique [0002] Lightning tripping of transmission lines has seriously affected the safe operation of my country's power grid. In order to improve the operational reliability of the transmission line, reduce the counter voltage generated by the line tower during lightning strikes, and maintain the lightning strike trip rate of the transmission line at a normal level, it is necessary to measure the impact grounding impedance of the line tower grounding device. At present, according to a large number of high-voltage technology and grounding-related teach...

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Problems solved by technology

At present, according to a large number of high-voltage technology and grounding-related teaching books published in my country, as well as the relevant grounding regulations in the power system industry specifications, the main method to obtain the impact grounding impedance of the tower grounding device is: by measuring the power frequency of the tower grounding device. Grounding resistance, and then multiplied by the impact coefficient, this method cannot directly and intuitively obtain the impact grounding resistance of the tower grounding device

The measurement method given in the standard DL / T 266-2012 Grounding Device Impulse Characteristic Parameters Test Guide is based on the traditional three-pole method in the measurement of grounding resistance. Two measurement lines need to be arranged during the measurement, and the grounding-related The basic knowledge given in the book and standard DL / T 266-2012 shows that the three-pole method is derived from the law of surface potential distribution in uniform soil. come error

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