US 12,424,840 B2
Generator circuit breaker control method based on short-circuit fault current symmetry
Fei Yang, Shaanxi (CN); Mingzhe Rong, Shaanxi (CN); Jinru Sun, Shaanxi (CN); Yifei Wu, Shaanxi (CN); Chunping Niu, Shaanxi (CN); Yi Wu, Shaanxi (CN); and Jun Wang, Shaanxi (CN)
Assigned to XI'AN JIAOTONG UNIVERSITY, Xi'an (CN)
Filed by XI'AN JIAOTONG UNIVERSITY, Shaanxi (CN)
Filed on Dec. 18, 2023, as Appl. No. 18/543,530.
Claims priority of application No. 202310029433.9 (CN), filed on Jan. 9, 2023.
Prior Publication US 2024/0235180 A1, Jul. 11, 2024
Int. Cl. H02H 7/06 (2006.01); H02H 1/00 (2006.01)
CPC H02H 7/06 (2013.01) [H02H 1/0007 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A generator circuit breaker control method based on short-circuit fault current symmetry, comprising the following steps:
step 1, disposing a main branch and a transfer branch on a generator circuit breaker, setting a correction coefficient α based on simulation of a short-circuit fault on an outlet side of a generator and measured short-circuit current data, and setting an early switching time threshold ε, a transferring current value Izy and circuit breaker disconnection waiting time β according to requirements of the generator circuit breaker;
step 2, collecting current on the outlet side of the generator in real time, a short-circuit fault occurring to the outlet side of the generator at a moment T0; when IN-1<Izy<IN, capturing a moment at which a current value is equal to the transferring current value Izy at a current rising stage and recording the moment as a moment T1; when IN′-2<IN′-1>IN′, capturing a moment at which the short-circuit current rises to the peak value and recording the moment as a moment T2, collecting current on the outlet side of the generator by discrete means, and denoting the moment T0 at which the short-circuit fault occurs to the outlet side of the generator as a 0 sampling point; IN-1 representing a current value at a (N−1)th sampling point, IN representing a current value at a N th sampling point, IN′-2 representing a current value at a (N′−2)th sampling point, IN′-1 representing a current value at a (N′-1)th sampling point, and IN′ representing a current value at a N′th sampling point; transforming discrete time coordinates into continuous time coordinates, to obtain T1≈(N−1)□Δt+δ, T2≈(N′−1)□Δt+δ, wherein Δt is a sampling interval;
step 3, starting to predict a transferring current feeding moment T4 and a main branch early switching moment T3 when a current peak value is collected, correcting the transferring current feeding moment T4 by the correction coefficient α, wherein T4=α□(T2−T1)+T2, predicting the main branch early switching moment T3=T4−ε by the early switching time threshold ε, and calculating generator circuit breaker switching waiting time Twait,
wherein Twait=T3−T2=α□(T2−T1)−ε, α is the correction coefficient; ε is the early switching time threshold; T1 is the moment at which the short-circuit current rises to the transferring current value; T2 is a short-circuit current peak value moment;
step 4, waiting for generator circuit breaker switching waiting time Twait after the short-circuit current peak value moment, and performing a circuit breaker switching command;
step 5, when the current drops to the transferring current Izy, feeding the transferring current through the transfer branch such that the short-circuit current on the main branch drops rapidly to 0 to realize rapid disconnection of the main branch; and
step 6, waiting for fixed time β after feeding the transferring current, and implementing disconnection of a fault circuit of the circuit breaker at a moment T5.