Relay Protection Simulation and Testing of Online Setting Value Modification Based on RTDS

Analyzing the feasibility of modifying setting values on the condition of the running line without exiting the protection function is of great importance for 110 kV substations. A system-level test of settings modification is proposed to verify that the values are correctly modified during the process and the protection function is still in effect. A cyber-physical automatic test bed using a real-time digital simulator (RTDS) is developed for relay protection to modify settings online, which distinctly improves work efficiency. Based on actual power grid parameters, a full-process closed-loop RTDS automatic control system is applied for performance testing when setting groups are changed. The experiments are focused on blocking time tests, setting groups switch and coverage tests, DC power supply intermittent tests, unwanted operations in setting value, changing load and protection starting tests, short-circuit fault tests and power system frequency oscillation tests. The results of the trial indicate that the automatic test bed is an effective technology for checking and verifying the reliability of modifying setting values online. In addition, 36 line protection devices from 12 relay protection manufacturers are tested. The reliability of each test item is analyzed and the relay performance is evaluated using a comprehensive method. The test bed provides reliable technical support for the design, engineering, commissioning and substation operation of online setting modification.