A Fault Diagnosis Method of Power Systems Based on Gray System Theory

Table 1

Working principle of protective relays and circuit breakers.

Number	Name	Corresponding action of protective relays and circuit breakers
	A	Fault: A; action: A; tripping: CB1 and CB2
	B	Fault: B; action: B; tripping: CB3 and CB4
	L1A	Fault: L1; action: L1A; tripping: CB2
	L1B	Fault: L1; action: L1B; tripping: CB3
	L2B	Fault: L2; action: L2B; tripping: CB4
	L2C	Fault: L2; action: L2C; tripping: CB5
	L1A	Fault: L1; unaction: L1A; action: L1A; tripping: CB2
	L1B	Fault: L1; unaction: L1B; action: L1B; tripping: CB3
	L2B	Fault: L2; unaction: L2B; action: L2B; tripping: CB4
	L2C	Fault: L2; unaction: L2C; action: L2C; tripping: CB5
	L1A	Fault: B; untripping: CB3; action: L1A; tripping: CB2; or fault: L2; untripping: CB3 and CB4; action: L1A; tripping: CB2
	L1B	Fault: A; untripping: CB2; action: L1B; tripping: CB3
	L2B	Fault: C; untripping: CB5; action: L2B; tripping: CB4
	L2C	Fault: B; untripping: CB4; action: L2C; tripping: CB5; or fault: L1; untripping: CB3 and CB4; action: L2C; tripping: CB5