光滑化非线性互补约束的节点类型转换模型

Bus Type Switch Model Based on Smooth Nonlinear Complementarity Constraints

提出一种用于描述潮流计算中PV-PQ节点转换逻辑的光滑化互补约束模型。电压控制节点的无功出力达到限制值后会失去对受控节点的控制,其转换关系能采用非线性互补约束模型描述。通过对互补约束条件的光滑化处理,并引入到潮流计算模型中,在迭代计算中可直接对节点类型进行判断并转换,将避免频繁的节点类型转换,显著提高计算的效率并得到正确的潮流结果。另外在连续潮流中考虑互补约束方程后,在临界点附近通过潮流不平衡量快速确定导致潮流不收敛的关键方程,从而有效识别出临界点类型和关键约束转换节点。通过对多个系统的仿真验证所提模型的有效性。

A bus type switch model for power flow computation based on smooth nonlinear complementarity constraints （NCC） equations was proposed in this paper. The PV bus voltage becomes uncontrollable when the output at the bus reaches the reactive power limit. By introducing the NCC model, the bus PV-PQ type switching logic was formulated as smooth NCC equations and incorporated into the power flow model. The bus type can be directly judged and switched within the iteration to avoid continually switching of the bus type, and obtain an accurate result and belter computation efficiency. In the solution of continuing power flow under consideration of NCC equations, the critical equations which induce power flow equation singularity can be quickly determined from the mismatch of power flow equations, so the critical point type and critical constraints switch bus can be correctly identified. The numerical results for several systems show that the proposed method is effective.