考虑负荷水平及有功备用的低频减载方案在线优化

Online Optimization of the Under Frequency Load Shedding Scheme Considering Load Level and Active Power Reserve

频率是电力系统运行的重要指标,当电力系统发生功率缺额时,系统频率会下降。低频减载是保障电网安全稳定运行的第三道防线。实际系统中,基于启动频率和动作延时的低频减载方案应用广泛,但传统的整定方法模型高度简化,等效参数不随负荷水平及有功备用变化而变化。为减少负荷切除总量,提出一种基于改进频率响应模型的在线低频减载优化方法,利用粒子群优化算法在线计算复杂模型等效参数,同时将粒子群算法应用到低频减载方案中,最大限度减少切负荷总量。仿真表明,相对于传统低频减载算法能有效减少有功负荷的切除,控制系统的频率,满足在线计算时长要求,论证了模型和算法的可行性和有效性。

Frequency is an important indicator in power system operation.When power shortage occurs in an electric power system,the system frequency will drop.Under frequency load shedding(UFLS)is the third line of defense for ensuring safe stable operation of the power grid.UFLS schemes based on start-up frequency and time-delay are widely used in actual systems.However,the conventional setting method uses a highly simplified model so that equivalent parameters do not change when load level and active power reserve change.An online UFLS optimization method based on an improved frequency response model was proposed to reduce total load ablation.According to this method,composite model equivalent parameters were calculated by using the particle swarm optimization(PSO)algorithm,and PSO was applied to the UFLS scheme so as to minimize total load ablation.Simulation results showed that the proposed approach could reduce ablation of active load and control system frequency more effectively than traditional UFLS so as to meet the duration requirement of on-line calculation,thus proving the feasibility and validity of the proposed model and algorithm.