Wide-area integrated impedance protection (WIIP) algorithm based on wide-area measurement system is proposed
for the purpose of improving the reliability and sensibility of fault component identification of wide-area protection.
Two commonly used methods nowadays in wide-area protection are the current differential protection (CDP) and the directional
pilot protection (DPP). The CDP, though responsive to all types of system faults, is subject to the distributed capacitance
and earth resistance of transmission line; the DPP, which is easy to implement and does not need much traffic, is
subject to system oscillations, conversion failure, and two phases operation. Integrating the advantages of these two algorithms,
WIIP is obtained by evaluating in virtue of the ratio of the average voltages to the sum of all incoming and outgoing
currents at each protected objects. The advantages of WIIP are verified by the fault analysis of two-terminal system
and multi-terminal system. The research results show that WIIP presented in this paper is more preferable than CDP in the
aspect of the sensitivity and DPP in the aspect of the dependability. The simulation effects can be obtained by using WIIP
method applied in the case of abnormal operations of relay protections, circuit breakers, measurement error scenarios and
substation DC failure.