A Fault Identification Method for High-Voltage Capacitors of DC Filters Based on Parameter Identification

Abstract

The invention discloses a method for identifying the fault of a DC filter high-voltage capacitor based on parameter identification. The multiplication identifies the equivalent capacitance value of the high voltage capacitor at the sampling instant. When the internal components of the high-voltage capacitor fail, the capacitance value decreases compared with normal operation, and the relative capacitance error increases. If it is greater than the threshold, it is judged as a fault in the area, an action signal is sent, and the protection device operates reliably; otherwise, the capacitance of the high-voltage capacitor is relatively large. If the error is smaller than the threshold, it is judged to be in normal operation, and the protection device will not act reliably. The method utilizes the voltage and current of the high-voltage capacitor to identify the parameters of the high-voltage capacitor, is applicable to DC transmission systems of any voltage level, and is not affected by DC system disturbance and AC system reclosing, and can identify faults accurately and reliably.

Description

technical field [0001] The invention relates to a fault identification method of a high-voltage capacitor of a DC filter based on parameter identification. Background technique [0002] High Voltage Direct Current (HVDC) has the advantages of large transmission capacity, long transmission distance and no need to consider synchronization issues. It has developed rapidly in the fields of long-distance power transmission and regional large power grid interconnection. Optimizing configuration played an important role. HVDC power transmission needs to convert AC to DC first. During the operation of its converter device, characteristic harmonics will be generated on the DC side, which will cause equipment heating, interfere with communication, and reduce the quality of power grid power supply. Therefore, a DC filter is usually configured on the DC side (at the DC bus) of the converter device. The double-tuned DC filter is composed of a high-voltage capacitor at the high-voltage ...

AI Technical Summary

Problems solved by technology

However, actual operating engineering experience and research show that this unbalanced protection scheme is susceptible to malfunctions due to system power changes, DC system disturbances, and AC system reclosing, with a high rate of malfunctions

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