Monitoring method and monitoring device for resistive current of zinc oxide lightning arrester

Abstract

The invention provides a monitoring method and a monitoring device for resistive current of a zinc oxide lightning arrester, wherein the monitoring device comprises a current measurement module, a phase voltage measurement module, a data acquisition module and a communication module. The current measurement module, the phase voltage measurement module and the data acquisition module are interconnected through the communication module. The current measurement module and the phase voltage measurement module measure leakage current and phase voltage of the lightning arrester and furthermore transmit the measured results to the data acquisition module through the communication module. The data acquisition module calculates the resistive current of the leakage current. The measuring method and the measuring device realize simple and quick measurement for the resistive current of the zinc oxide lightning arrester and furthermore have high practical significance for maintaining normal operation of the zinc oxide lightning arrester.

Description

technical field [0001] The invention relates to a method and device for monitoring current, in particular to a method and device for monitoring resistive current of a zinc oxide arrester. Background technique [0002] In the high-voltage power grid, MOA (Metal Oxide Arrester) is a protective device for protecting electrical equipment from overvoltage. Due to the superior nonlinear characteristics and good flow capacity of the zinc oxide arrester, it has been widely used in the power sector and its users. However, with the extensive use of the zinc oxide arrester, the accident caused by the zinc oxide arrester itself is Power accidents caused by equipment damage also occur, especially high-voltage zinc oxide arresters, once an accident occurs, it will cause huge losses to users. Therefore, on the basis of continuously improving the manufacturing level of zinc oxide arresters and ensuring the manufacturing quality of zinc oxide arresters, actively carrying out research on the...

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Problems solved by technology

[0005] 2. Temperature has a great influence on the online monitoring of MOA insulation characteristic parameters

[0006] 3. When the relative humidity is low, the MOA insulation characteristic parameters change little with the relative humidity, but as the relative humidity continues to increase, its insulation characteristic parameters increase sharply, and the full current when the relative humidity is 70% is approximately 2.3 when the relative humidity is 10%. times, the increased leakage current is mainly the fundamental wave component of the resistive current, the fundamental wave component of the resistive current has increased dozens of times, and there is obviously a pulse discharge phenomenon in the leakage current when the relative humidity is high

The disadvantage is that it is not sensitive to the early aging of MOA. In the initial stage of MOA operation, in the full current flowing through normal MOA, the resistive component only accounts for 10%-20% of the full current. In this way, even if the resistive component has increased significantly , the change of the full current is still very insignificant

[0008] In the traditional full current measurement method, the capacitive current of the zinc oxide arrester accounts for a large component, while the resistive current component in the full current accounts for a small proportion of the full current, but it can reflect the internal quality of the zinc oxide arrester. Therefore, it is necessary to study a measurement method that can quickly, correctly and effectively reflect the resistive component of the zinc oxide arrester

[0009] In addition, the current live or online monitoring equipment for zinc oxide arresters in China mainly adopts the method of centralized wired collection. The two electrical signals of PT voltage and leakage current are connected to the same device through the test cable for comparison, analysis and calculation. However, due to the distance between devices Far away, the test needs to connect a very long test cable, and the wiring and collection of the cable bring a huge workload to the staff

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