Differences and Cause Analysis of Pressurizer Pressure Control Response

The early commercial nuclear power plants in China requires digital transformation. Against the differences of pressurizer pressure control response under accident condition before and after the digital transformation of Daya Bay Nuclear Power Plant, by comparative analysis of pressurizer pressure control response curve and Proportion-Integral-Derivative (PID) controller algorithm in several nuclear power plants with different Digital Instrumentation and Control System (DCS) platforms, this paper finds out the cause of control discrepancy and proposes a scheme to increase the PID regulation range and add switch logic between open and closed loops, which combines the advantages of incremental and positional PID controllers in the control system. The pressurizer pressure control performance is improved, and it has been verified in reactor trip test of a nuclear power plant.The optimization method of the pressurizer pressure controller proposed in this paper has good reference value and significance for the subsequent digital transformation of nuclear power plants.