Research On High-voltage Shunt Reactor Applications In UHV Transmission System

UHV charging power is large. It is need to set shunt reactors to compensate. Since thefixed capacity of the reactor cannot be adjusted, high degree of compensation will make thegrid voltage excessive reduction in the heavy, increase the line loss, and the transmissionpower is greatly limited. Dynamic Compensation controllable reactor is an effectivesolution.In this paper, magnetic saturation transformer in EMTP simulation software to buildthe model, and gain control characteristics and response time characteristics were verified.From suppress power frequency overvoltage, limit arc current and avoid resonanceover-voltage three angles analysis of the controllable reactor setup parameters, proposed amethod to determine the degree of the shunt’s compensation and compensation of the upperand lower limits. Factors affecting the power frequency overvoltage analyzed, studied thedifferent ways of compensating frequency over voltage characteristics, analyzed therelationship between the compensation degree of shunt and power frequency overvoltage.The principles of arc current generated by the analysis, from the perspective of fullycompensating phase-phase capacitor, proposed neutral small reactor formula of single-loopand double-loop. From the perspective of arc current suppression, analyzed the relationshipbetween the neutral small reactance and compensation degree. Detailed analysis theresonance principles caused by two factors. From the perspective of small neutral reactancedeviation and frequency deviation, analyzed the relationship between resonance andcompensation degree.Through simulation and summary, according to the need of suppressing powerfrequency overvoltage, proposed a method to determine the shunt’s compensation mode andcompensation degree of the upper and lower limits. According to the need of limiting arccurrent, proposed a method to determine the shunt’s compensation degree of lower limits,proposed neutral small reactor formula of single-loop and double-loop. According to the need of avoiding resonance over-voltage, proposed a method to determine the shunt’scompensation degree of upper limits in the most serious cases (Neutral small reactorimpedance value is small, the frequency decreased).