Title :
The influence and countermeasure to transformer differential protection of CT saturation caused by external fault removal
Author :
Gu, Jun ; Zheng, Tao ; Huang, Shaofeng
Author_Institution :
Key Lab. of Power Syst. Protection & Dynamic Security Monitoring & Control, North China Electr. Power Univ., Beijing
Abstract :
The mal-operation of transformer differential protection will occasionally take place after the removal of external fault due to current-transformer (CT) saturation. Study show that CT saturation can be divided into three kinds. Firstly, the influencing factors of CT saturation and effect of CT saturation to transformer differential protection are studied. Secondly, this paper analyzes the characteristic of the operating point when differential protection is mal-operated because of CT saturation. At last a method of different time delay in different areas is presented to prevent the differential protection from mal-operation. Simulation results validate its feasibility and reliability. It is significant if the method is realized for transformer protection.
Keywords :
current transformers; fault diagnosis; power transformer protection; CT saturation; current transformer; different time delay method; external fault removal; mal-operation prevention; operating point characteristic; transformer differential protection; Circuit faults; Current transformers; Fault currents; Hysteresis; Magnetic flux; Magnetization processes; Power system protection; Power system transients; Saturation magnetization; Surge protection;
Conference_Titel :
Electrical Machines and Systems, 2008. ICEMS 2008. International Conference on
Conference_Location :
Wuhan
Print_ISBN :
978-1-4244-3826-6
Electronic_ISBN :
978-7-5062-9221-4
