Overvoltage measuring sensor for overhead transmission line based on coupling electric field

Abstract

An overhead transmission line overvoltage measurement sensor based on coupling electric field relates to the structure of an overhead transmission line overvoltage on-line monitoring sensor. The invention mainly includes a sensor shell, an insulating pad, a fixing plate, a voltage dividing capacitor group, a matching resistor, a coaxial cable, an inner shielding shell, a data acquisition unit and the like. The invention has the characteristics of simple structure, convenient loading and unloading, low cost; high accuracy of measuring overvoltage, good linearity and high precision; strong versatility, wide application range, safe and reliable use, etc.; Overvoltage online monitoring. The invention can be widely used in the online monitoring of overvoltage of overhead transmission lines, and is especially suitable for the online monitoring of overvoltage of 110kV-1000kV high-voltage overhead transmission lines.

Description

[0001] The invention belongs to the technical field of power system overvoltage measurement, and in particular relates to the structure of an overvoltage on-line monitoring sensor for overhead transmission lines. Background technique [0002] The safe production of the power system is closely related to the security of national property and the interests of people's lives. In our country, lightning damage is the most important factor affecting the safe operation of power system. Overhead transmission lines are erected in the air and exposed to the atmosphere, so they are prone to lightning overvoltages, especially high-voltage transmission lines are higher from the ground and are more susceptible to lightning damage. According to statistics, among the many causes of line faults, the number of trips caused by lightning strikes on high-voltage overhead transmission lines in my country accounts for 40% to 70% of the total number of trips. Therefore, in order to propose effective...

AI Technical Summary

Problems solved by technology

The main disadvantages of the sensor are: ① Since the sensor is installed under the overhead transmission line, it is fixed on the tower by bolts and nuts, and it is 1~30m away from the overhead transmission line.

When the distance between the sensor and the overhead transmission line is more than 15m, the coupling capacitance value between the sensing plate and the overhead transmission line is far away, which leads to an excessively large voltage division ratio, resulting in a small overvoltage signal and making the collected data signal noisy. lower than

②The sensing metal plate of the sensor is a square or round flat plate, which is very easy to accumulate dirt, water, or even ice on the surface, resulting in a change in the sensor’s partial pressure ratio, causing distortion of the measured overvoltage waveform, reducing the sensor’s measurement performance, and resulting in inaccurate Reduce the accuracy of overvoltage measurement

③The accumulated water on the induction plate or the ice water on its surface after the melting of ice can easily penetrate into the stainless steel shielding box through the threaded through hole in the middle of the induction plate and the gap with the insulating support, reducing the electrical resistance of the voltage dividing capacitor and matching resistor. performance, even destroying voltage divider capacitors and matching resistors

Causes the sensor to fail and cannot monitor the overvoltage of the overhead transmission line

④When the sensor is covered with ice, the weight of the sensor will increase with the increase of the amount of ice, which will easily cause the sensor to fall off from the tower. Not only will the sensor fail to work, but it will even cause power system operation accidents

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