Huadian Technology ›› 2010, Vol. 32 ›› Issue (5): 41-43.

• 技术交流 • Previous Articles     Next Articles

easures for preventive saturation of current transformer in relay protection devices

ZHOU Huanrong1, CHEN Qi1, LI Bingjun1, SONG Yun2   

  1. 1.Guodian Nanjing Automation Corporation Limited, Nanjing 210003, China; 2.Nanjing Zeming Electronic Corporation Limited, Nanjing 210003, China
  • Received:1900-01-01 Revised:1900-01-01 Online:2010-05-25 Published:2010-05-25

Abstract: In the power system and the large or medium generator transformer set with the voltage level higher than 35kV, the short circuit fault current often includes two components: one of them is the periodic component with the power frequency, and the other is aperiodic component, which is damped along with time (it called direct current component sometimes). This characteristics of the fault current are easily to cause saturation of the secondary windings of CT in protection devices, and further cause the protection incorrectly tripping or refusing to trip. The process and the reason of CT saturation were analyzed, and relevant protective measures were put forward, and the reliability of the protection was enhanced.

Key words: relay protection, current transformer (CT), aperiodic component, CT saturation