Title :
Adaptive Impedance Relay With Composite Polarizing Voltage Against Fault Resistance
Author :
Liu, Q.K. ; Huang, S.F. ; Liu, H.Z. ; Liu, W.S.
Author_Institution :
North China Electr. Power Univ., Beijing
fDate :
4/1/2008 12:00:00 AM
Abstract :
As the conventional relay usually takes the bus voltage as a polarizing voltage, its operating characteristic is fixed and cannot adapt to fault resistance. To enhance the capability against fault resistance, based on the compensated voltage changing with fault resistance, a kind of adaptive impedance relay with composite polarizing voltage is presented in this paper. On the other hand, the operating boundary of the adaptive relay may enter into an ldquoinphaserdquo area along with the increase of fault resistance. To prevent the adaptive relay from maloperation in the ldquoinphaserdquo area, a new additional blocking component is also proposed. Both the adaptive relay and the blocking component were all analyzed in the voltage plane and the impedance plane. Theoretical analyses show that both of them have circular characteristics with greater resistive tolerance. The performance of the relay has been demonstrated on a two-source 500-km line 750-kV system.
Keywords :
power system relaying; power transmission faults; power transmission lines; power transmission protection; relay protection; adaptive impedance relay; blocking component; composite polarizing voltage; fault resistance; power system relaying; power transmission protection; voltage 750 kV; $mho$ relay; Adaptive relaying; extremely high voltage (EHV) transmission lines; impedance measurement; power system faults; power system relaying; power transmission faults; power transmission protection; protective relaying; resistance;
Journal_Title :
Power Delivery, IEEE Transactions on
DOI :
10.1109/TPWRD.2007.916021