Abstract: Abstract:Secondary disasters will occur inevitably after power outage in whole plant scope, so to implement black start quickly is of important significance for a power plant. The correct selection of black start supply is the foundation of successful blackstart. Aiming at the tripout accident of three of the four output transmission lines of Togtoh Power Generation Company Limited at November 2012 caused by extreme weather, a optimized design of blackstart power supply system was carried out, in which the selection of the power source place, the protection configuration, the operation mode, the fivepreventing system, the electric energy metering system and others were considered. After the scheme was implemented in Togtoh Power Generation Company Limited, the blackstart was realized successfully and effectively, and favorable economic benefit and social effect were obtained.

Key words: Key words:black start power supply, protection device, fivepreventing system, electric energy metering system, dual power supply, optimized design