Study on the On-line Adaptability of Comprehensive Protection Settings to the Auxiliary Power Running Mode

Abstract

The comprehensive protection setting process of auxiliary power in a plant is always an off-line mode, the protection settings are always calculated according to the harshest conditions under off-line state, therefore the protection sensitivity is decreased, that makes even the back-up protection be ineffective. This article proposed a scheme concentrated on how to make the protection settings adapt to the on-line running mode automatically, in this solution the protection settings in running could change their values automatically according to the changes of the running mode of auxiliary power, then the protection sensitivity will be automatically increased when the generator load is low, the auto-starting capacity will be automatically limited by using some measures when the generator load is high, to control the setting values not to exceed the limited value, and to ensure the comprehensive protection equipment working in an effective way, This paper also proposed that all the auxiliary power protection equipment should be designed as a whole system to make the comprehensive protection setting process associating with the running mode of auxiliary power, so the protection settings could adapt to the on-line running mode of auxiliary power automatically.