Phase-Space-Based Pilot Main Protection for a Transmission Line Immune to Timing Attack and Controllable Shunt Reactors

Pilot current differential protection for transmission lines is an important part of ensuring the safety of the power grid. The loss of data synchronization due to cyberattacks and the uncertain compensation degree of controllable shunt reactors will evidently deteriorate the performance of pilot current differential protection and may lead to the maloperation of the protection if no effective countermeasure is implemented. To address the above-mentioned problems, a novel line pilot protection criterion based on the recognition of the phase space trajectory is proposed. First, the basic principle of phase space and its parameter selection scheme are analyzed. Then, the fault component instantaneous power difference (FCIPD) is selected as the time series for phase space reconstruction, and the distribution characteristics of the phase space trajectory of the FCIPD under different conditions are analyzed. Subsequently, a novel pilot main protection criterion for a transmission line is proposed. PSCAD/EMTDC-based simulation results verify that the proposed criterion is immune to timing attack and controllable shunt reactors and has the advantages of free setting, high speed, and high-fault-resistance tolerance capability.