Optimization of Lateral Interlock Protection for Thermal Power Units

Abstract

According to the Twenty-Five Key Requirements for Preventing Electric Power Production Accidents, the protection of important capital and auxiliary equipment should adopt the “Two Out of Three” logic judgment method, and the protection signal should follow the whole process from the sampling point to the input module. The principle of relative independence is that the number of measuring points is insufficient due to system reasons, and measures to prevent disoperation should be taken. Considering that a coal-fired power plant’s third-phase engineering steam turbine, boiler, and generator lateral protection signals are single-point design and do not meet the requirements of countermeasures, the abnormality of a single circuit of the protection signal will cause abnormal protection actions and affect the safe and stable operation of the unit. Therefore, the original control strategy is systematically optimized by adopting the “Two Out of Three” logic and successfully passes the ETS, DEH, FSSS, and lateral interlock protection tests. The result provides a reference for equipment malfunction in the operation of the same type of units.