Annex 10 Contd.......

Preventive Maintenance Schedule for Protection Systems

S. No.	Tasks assigned	Shut Down (SD) Or Without Shut Down (WSD)	Periodicity
B.	UNIT PROTECTION
	P 40
	Starters: NPS – impulse	WSD	Yearly
	Non-impulse	WSD	Yearly
	PPS-impulse	WSD	Yearly
	Phase sequence check	WSD	Yearly
	DC supply check	WSD	Yearly
	Transmitter checks	WSD	Yearly
	Receiver checks	WSD	Yearly
	Modulation threshold	WSD	Yearly
	Reflex test	WSD	Yearly
	Comprehensive test	WSD	Yearly
	End to end test	WSD	Yearly
	Trip contacts check	SD	Yearly
	Annunciation check	SD	Yearly
	Check for carrier send	SD	Yearly
	Auxiliary relays healthiness	SD	Yearly
	Over voltage relays	SD	Yearly
	LBB	SD	Yearly
	STUB protection	SD	Yearly
	Fault locater initiation check	SD	Yearly
	DR H initiation check	SD	Yearly
	Auto release check	SD	Yearly
	DC logic	SD	Yearly
	REACTOR PROTECTIONS
	Reactor back up impedance	SD	Yearly
	Carrier send for remote trip	SD	Yearly
	Auxiliary relays (Buchholz. PRV. Etc)	SD	Yearly
	Reactor differential protection	SD	Yearly
	REF protection	SD	Yearly
	DC logic	SD	Yearly
	AUTO TRANSFORMER PROTECTIONS
	Over fluxing relay	SD	Yearly
	Over load	SD	Yearly
	Directional over current	SD	Yearly
	LBB	SD	Yearly
	Auxiliary relays (Buchholz. PRV etc.)	SD	Yearly
	Fuse failure check	SD	Yearly
	Transformer differential protection.	SD	Yearly
	Restricted earth fault	SD	Yearly