基于电力网络一次调频动态模型建立及仿真

传统一次调频(PFR)模型忽略网络和电厂炉侧主蒸汽压力约束;不计主蒸汽压力对发电机出力影响,认为发电机功率-频率响应是线性关系。充分考虑锅炉、汽机、负荷、电网之间相互配合和制约关系,考虑发电机频率响应的非线性因素并建立了基于实际电力网络的PFR动态模型。该模型可用于分析电力网络各环节PFR动态响应对频率稳定的贡献,体现发电机、负荷和电网动态PFR综合能力。通过对IEEE 30节点系统进行仿真,分析了网络、炉侧对PFR的影响、约束对PFR的影响和线路跳线故障,并得出结论:当机组运行在上限、限载或部分机组没有并入PFR都会使电网的PFR能力下降;系统管理者应正确管理PFR服务,加强参数管理,合理调度潮流,使机组尽量不在接近约束的情况下运行,确保机组在需要时能释放出PFR容量抑制频偏;频偏出现后,系统管理者应合理调度二次调频(SFR)使频率尽快返回基值,并使系统整体PFR能力得到恢复。

Grid-based PFR dynamic modeling and its simulation

Traditional PFR(Primary Frequency Regulation) model ignores the constraints of power network and main steam pressure of boiler,which supposes the relation between generator power output and frequency to be linear by neglecting the influence of main steam pressure on power output.Improved PFR dynamic model is established based on real power grid,which fully considers the cooperative and restrictive relationship among boiler,turbine,load and grid,as well as the nonlinear relation between generator power output and frequency.It can be used to analyze the contribution of each element to frequency stability,which embodies the comprehensive PFR ability of generator,load and grid.With IEEE 30-bus test system,the influence of grid,boiler and their constraints on PFR are studied and the frequency response to transmission line trip is simulated.The conclusions are:when the generator operates at upper limit or there are generators not included in PFR,the system PFR ability will be decreased.SO(System Operator) should supervise PFR service properly,enhance parameter management,dispatch power flow rationally and avoid the operation of generator at upper limit to ensure the release of PFR reserve when needed to suppress frequency deviation after disturbance.When frequency deviation happens,SO should supervise SFR(Second Frequency Regulation) properly to bring frequency back to base point and renew the whole system PFR ability as soon as possible.