基于初值估算和潮流可控范围的UPFC潮流收敛特性研究

变流器电压初值不合理或潮流设定值过大，将导致含统一潮流控制器(UPFC)电网潮流收敛到实际不可行解，或超过串联变流器的电压约束范围。提出基于初值估算的两阶段潮流算法，根据第一阶段常规潮流结果估算串联变流器电压相角，将其作为第二阶段潮流初值，解决了潮流收敛性对变流器电压初值敏感的问题。利用拓展雅可比矩阵，建立UPFC串联控制变量对潮流控制目标可调范围的灵敏度模型，量化串联变流器电压对潮流控制范围的影响，避免因控制目标不合理引起潮流发散或串联变流器电压越限。算例结果验证了所提算法的可行性和正确性。

Power flow convergence characteristic of UPFC based on initial value evaluation and controllable range of power flow

The unreasonable initial voltage of converter or too large setting value of power flow will cause the power flow of power system with UPFC(Unified Power Flow Controller) converge to infeasible solution or exceed the voltage constraint range of series converter. A two-stage power flow algorithm based on initial value estimation is proposed. The voltage phase angle of series converter is estimated according to the conventional power flow in the first stage, which is set as the initial power flow value of the second stage. It solves the problem that the convergence of power flow is sensitive to the initial value of converter voltage. The Jocabian matrix is extended to build the sensitivity model of the series control variable of UPFC to the controllable object range of power flow, which quantifies the impacts of the voltage of series converter on the controllable range and avoids the divergence of power flow or voltage violation of series converter caused by unreasonable control objects. The case results verify the feasibility and correctness of the proposed algorithm.