A New Adaptive Backup Protection Scheme Based on Intelligent Electronic Devices

A new adaptive interphase backup protection scheme based on intelligent electronic devices (IEDs) is proposed in this paper. When the system is in normal operation state, the backup protection areas are divided according to the operation status and topology of the primary and secondary devices in the power grid. When fault is detected in the system, each IED will search for the other IEDs in the same protection area and exchange the voltage and current synchronized phasor information with them. On this basis, the adaptive action factor is constructed according to the proportional relationship between the phase voltage difference and phase current after the fault. Then, by comparing and analyzing different characteristics of the adaptive action factor in normal operation state and in fault state, the adaptive interphase backup protection can be realized. Simulation results verify that the proposed method is able to identify the fault fast and accurately. It is highly sensitive to different types of interphase faults and could operate reliably even when the fault location, system structure, or system operation mode changes.