Rankin, Hill & Clark LLP
Relay protection method and apparatus against LC parallel circuit detuning faults
A relay protection method against LC parallel circuit detuning faults comprises the steps of: a relay protection device samples a current of a parallel LC, that is, a reactor and a capacitor, and samples a total current flowing through the whole LC; convert the current of the reactor into a current of an equivalent capacitor; calculate amplitudes of the current of the equivalent capacitor and a current of a realistic capacitor and calculate an amplitude of the total current flowing through the LC; calculate a current amplitude ratio of the equivalent capacitor to the realistic capacitor; and when the amplitude of the total current flowing through the LC is large enough, send an alarm signal or a trip after a setting time delay if the current ratio exceeds a preset upper and lower limit range. Also provided is a corresponding relay protection device.
NR ELECTRIC CO., LTD. NR ELECTRIC ENGINEERING CO., LTD.
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Baoli Jun Yaoyao Huazhong Shouping Jie Guang Qixue Wei
Xu Chen Ji Li Zhong Zhang Wang Zhang Yan