The effect of load models on electromagnetic transient stability in AC/DC power systems

Load models have great impacts on power system simulation, operation and stability. In order to analyze the effects of load models on power system stability, this paper establishes the two-area four-machine system, and the tie lines between the two areas is replaced with the HVDC line which is modified based on CIGRE HVDC Benchmark. Then the behaviours of the load models under the transient stability and small signal stability are simulated. The simulation results demonstrate that the load models have great impacts on the AC/DC power system stability. Meanwhile, the lack of reactive power may lead to voltage instability of AC/DC power system, owing to the load characteristics and the recovery features of HVDC system.