A series capacitance compensation line distance protection method combined with a phase comparison relay

Abstract

The invention discloses a novel series capacitor compensation line distance protection method combined with a phase-comparison relay. Compensation voltage is calculated from the current and voltage value at the protection installation. 2) Phase comparison relay action discrimination: compare the phase according to the calculated compensation voltage and the corresponding positive sequence voltage at the protection installation; 3) Protection logic: if the phase comparison relay operates, then Directly open distance protection without any anti-overrunning measures; if the phase comparison relay fails to operate, it will be put into level detection logic. The invention improves the sensitivity of the distance protection on the basis of reliably preventing overrunning. When the compensation capacitor is installed at the end of the line, the sensitivity of the distance protection is basically not affected by the compensation capacitor, has high reliability and is easy to realize.

Description

technical field [0001] The invention relates to a novel series capacitance compensation line distance protection method combined with a phase-comparison relay, which belongs to the technical field of power system automation. Background technique [0002] Series capacitor compensation is an effective means to improve the economy and reliability of transmission system. Its main function is to: improve the transmission capacity of the power system by controlling the power flow; improve the stability of the power system; improve the voltage quality and reactive power balance; reduce the line loss of the system, increase the transmission capacity of the line, and also improve the transient stability of the system , Optimizing the power flow of transmission lines. [0003] However, the series compensation capacitor destroys the uniformity of the transmission line impedance, which brings great difficulties to the design of series capacitor compensation line protection, especially ...

AI Technical Summary

Problems solved by technology

One is to avoid the impedance setting value of the distance I section, that is, consider the capacitance reactance ZC of the series compensation capacitor when setting, and set it according to the sum of the line impedance ZL and the capacitance reactance of the series compensation capacitor (ZL-j|ZC|), When the series compensation capacity is large, the protection sensitivity may be very low, or even have no sensitivity; second, the level detection scheme, that is, assuming that the voltage on the series compensation capacitor is always at its overvoltage protection level, the failure before the series compensation capacitor or in the series There is still a problem of insufficient sensitivity of the distance protection when the capacitor is faulty and the series capacitor is bypassed by the air gap

Therefore, the distance protection in the current series capacitor compensation line protection is often withdrawn

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