Series capacitor compensation circuit distance protection method by combining phase-comparison relay

Abstract

The invention discloses a novel series capacitor compensation circuit distance protection method by combining a phase-comparison relay. The method is characterized by comprising the following steps: 1) calculation of compensation voltage: using the series capacitor installation position (before capacitors) as a compensation point, and utilizing the current and voltage values on the protection installation position to calculate compensation voltage *S; 2) action judgment of the phase-comparison relay, carrying out phase comparison on the calculated compensation voltage *S and the correspondingpositive sequence voltage on the protection installation position; 3) protection logic, if the phase-comparison relay acts, the distance protection is directly carried out without overriding measures;if not, the level detection logic is carried out on failure of the phase-comparison relay. The invention can enhance the sensitivity of distance protection on the basis of reliable overriding prevention. When a compensation capacitor is arranged at the tail end of the circuit, the sensitivity of distance protection is basically free from the effect of the compensation capacitor, the reliability is high, and the distance protection 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,

Images