A 500kv system air-closing belt high-resistance line DC bias suppression method

Abstract

The invention discloses a method for suppressing DC bias of a 500kV system air-closing belt with a high-resistance line, which includes the following steps: Step 1: detecting a circuit breaker closing trigger signal; If the circuit breaker closing trigger signal is not received, continue to step 1; Step 3: If the circuit breaker closing trigger signal is received, it is necessary to further determine whether it is an air-closing line operation; if it is a non-air-closing line operation, Then the circuit breaker executes the three-phase fast closing action; Step 4: If it is an air-closed line operation, the circuit breaker will follow the set A-phase target closing delay, B-phase target closing delay and C-phase target closing delay. , the three-phase delay closing action is performed to suppress the air-closing with high-resistance line DC bias. The invention can significantly reduce the zero-bias time of the empty charging current, effectively prevent the occurrence of arc reignition or failure to break normally when the circuit breaker is opened during the empty charging process, and ensure the safe and stable operation of the power system.

Description

Technical field: [0001] The invention belongs to the field of power transmission, and in particular relates to a method for suppressing the direct current bias of a 500kV system air-closing belt high-resistance line. Background technique: [0002] For the 500kV ultra-high voltage line running with high resistance, there will be a current DC bias phenomenon when the line is air-closed, that is, the empty charging current flowing through the circuit breaker contains a large DC component and decays slowly, making the current unstable for a long time At the zero crossing point, if the circuit breaker needs to be opened due to a fault at this time, it may cause the circuit breaker to fail to extinguish the arc or the arc will re-ignite multiple times, which is not conducive to the safe and stable operation of the power system. Therefore, for 500kV lines with high The DC bias problem is very important during the charging process. [0003] Research institutes at home and abroad ha...

AI Technical Summary

Problems solved by technology

[0004] The above research work covers the generation mechanism, influencing factors and suppression methods of the DC bias phenomenon of the air-to-air circuit, which is of great significance for reducing the zero bias time and reducing the risk of circuit breaker re-breakdown. However, there are still certain limitations, especially in the suppression In terms of method research: In the case of excessive compensation, the closing resistance of the circuit breaker has limited suppression effect on the DC component, and the configuration of the closing resistance of the circuit breaker will increase the failure rate of the circuit breaker itself; the phase control closing technology is carried out In the research, the phase-by-phase closing technology of zero-crossing detection is adopted. Due to the need for matching detection devices, it is difficult to realize, the cost is high, and there are few practical applications.

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