Consideration of generator excitation current limitation for the improved continuation power flow

The nature of voltage collapse is that as power transfers into a well-bounded region are increased, the voltage profile of that region will become lower and lower until a point of collapse is reached. Continuation power flow (CPF) is a powerful analytical methodology and tool in static voltage stability analysis. Engineer may use P-V method for general voltage stability evaluation, contingency screening, etc. The benefits of this methodology is that it provides an indication of proximity to voltage collapse throughout a range of load levels or interface path flows for the simulated system topology. The reactive power resources are needed to supply the requirements of customer demands and the reactive power losses in the transmission and distribution systems, and provide adequate system voltage support and control. Therefore, the modeling of generator reactive power limit is very important in CPF. The reactive power characteristic under generator excitation current limit were discussed; Based on the former generator reactive power limit treatment, a new method of reactive power dispatch under the excitation current limit adapted in CPF calculation was given out; Simulation used the improved algorithm were done. The simulation results of the IEEE 30 system show that the proposed model is effective and rational.