Method for monitoring resistant current in leakage current of an arrester

Abstract

The invention discloses a method for monitoring the resistance current of leakage current in lightning arrester that includes following steps: collects the whole leakage current through the lightning arrester; the whole leakage current is divided into the resistance current and the capacitive current; and the two kinds of current are scaled to mA grade; decides the time that two current thorough the zero point, and measures the average value of the resistance current and the capacitive current at the same time, and the value is as the original standard value; measures the max value of two kinds of current at power frequency 20ms, and records the change of current, and compares the difference of change rate of current; when the current change of instantaneous max value is keep constant rising, and detects the value is reach the 10% of original standard value; If the said detection result is true, and then the resistance element is changed to make the average value of the capacitive current return to the original standard value, and detects the average value of the resistance current. The method can obtain the change trend of resistance current when the lightning arrester is degraded seriously.

Description

Technical field [0001] The invention relates to an on-line monitoring method for leakage current in the operation of high-voltage electrical equipment, in particular to an AC gapless 110KV metal zinc oxide lightning arrester, which uses the analysis of the leakage current (also called full current) of the arrester to obtain the resistance An on-line detection method based on the value of the electrical current. Background technique [0002] Zinc oxide arrester is a kind of protective equipment to protect electrical equipment from overvoltage. Due to the superior non-linear characteristics and good current flow capacity of zinc oxide arresters, they have been accepted and widely used by users in the power sector. However, with the large-scale use of zinc oxide arresters, the occurrence of accidents in the arrester itself leads to the occurrence of protected electrical equipment. Damage and electrical accidents have also occurred, especially zinc oxide arresters with voltage levels...

AI Technical Summary

Problems solved by technology

Although this method can reflect certain valve aging problems, it is not so sensitive to other problems (such as internal moisture, partial discharge, etc.)

[0007] In addition, the resistive current of the MOA during operation is only tens of microamperes, and the signal coupled to the secondary detection circuit through the transformer is already extremely weak, while the electric field, magnetic field, and phase-to-phase interference of the high-voltage line in the substation are enough to produce a weak signal waveform. Difficult to overcome various influences, resulting in errors, offsets or instability in measurement results

Therefore, so far, there is no truly stable and reliable MOA resistive current monitoring technology recognized by the power industry.

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