核电机组接入电网的低频保护综合风险评估模型与方法

Model and Method of Low Frequency Protector's Synthesized Safety Risk Assessment for Nuclear Power Plant Connected to the Grid

将风险评估理论应用于核电接入电网的协调控制中,提出了核电接入电网的低频保护综合风险评估模型及方法。该方法提出评估系统频率降低对厂网影响程度的低频风险指标和考虑低频保护装置工作机理的装置风险指标,建立低频风险综合模型,构建安全风险矩阵,计算核电厂主泵和汽轮机低频保护及电力系统自动低频减载装置的综合风险值及风险变比值,分析风险因素的安全风险价值和保护装置的低频风险敏感度。算例分析验证了风险模型及方法的有效性,可以为核电厂低频涉网保护装置与电网安全自动装置的参数整定及协调控制提供参考。

The safety risk assessment theory was applied in coordination control of grid with nuclear power units. The model and method of low frequency protector＇s synthesized safety risk assessment, for grid with nuclear power units, were put forward. Synthesized safety risk assessment method related to low frequency risk index used to evaluate the influence caused by frequency decreasing on NPPs and grid, and device risk index based on the protectors＇ mechanism. The synthesized risk model was established, the safety risk matrix was structured afterwards. Synthesized safety risk value as well as risk variation value of low frequency protectors, including NPP＇s cooling main pump steam low speed protector, turbine low frequency protector, and power system＇s automatic low frequency load shedding device, were calculated. Based on which, risk index＇ safety risk value and protectors＇ safety risk sensitivity were analyzed. Modeling simulation demonstrated the rationality of risk method and the effectiveness of the risk model. The model provides theoretical foundation and reference basis to protectors＇ parameter-optimized scheme as well as the coordination and cooperation between NPP and grid.