An Adaptive PMU-Based Wide Area Backup Protection Scheme for Power Transmission Lines

TLDR

The paper proposes an adaptive wide‑area backup protection scheme for transmission lines. The scheme uses synchronized phasor measurements to form backup protection zones, identifies the faulted zone via increased sequence currents, and applies a linear least‑squares method on voltage and current phasors to locate the faulted line and its position, demonstrated on WSCC 9‑bus and IEEE 118‑bus systems. The method delivers a closed‑form, noniterative solution that accurately identifies the faulted line and its location regardless of fault type, resistance, or measurement errors, as confirmed by simulations on standard test systems.

Abstract

This paper proposes a novel adaptive wide area backup protection scheme for transmission lines. In the proposed scheme, both the faulted line and fault location are determined by a limited number of synchronized phasor measurements. Based on phasor measurement unit placement and network topology, subsets of lines and buses called backup protection zones (BPZs) are formed. After a fault occurs in the transmission network, the sum of zero- and/or positive-sequence currents entering the faulted BPZ highly increases, and hence, the faulted BPZ can be determined. The linear least squares method is then used to determine the faulted line, as well as the fault location by voltage and current phasors of the faulted BPZ. Accordingly, the proposed scheme provides a closed-form and noniterative solution for the faulted line and fault location identification problem. On the other hand, it readily determines the faulted line regardless of the fault type, fault resistance, and measurement errors. To show the effectiveness of the method, it is applied to the WSCC 9-bus and IEEE 118-bus test systems. Simulation results verify successful identification of the faulted BPZ as well as the faulted line within the faulted BPZ with limited measurement points.