Power Load Modeling Considering Load Low-voltage Releasing Characteristics

In this paper, a novel load model structure considering multi-level low-voltage release characteristics is proposed. In the proposed model, three-level low-voltage release characteristic parameters are introduced into the existing synthesis load model (SLM) to simulate the load low-voltage release characteristics during disturbance. Next a load model parameter calculation method considering load multilevel low-voltage release characteristics is proposed. Calculating the per-unit value of a single device type real load power relative to the total load node real power, and using the per-unit value as a weighted factor for polymerization, the each stage action voltage and low-voltage release average delay time constant in the synthesis load of low-voltage multi-level release characteristic parameters can be derived. Then based on the percentage of actual load losses after disturbance, multilevel low-voltage release proportion parameters is determined by fault fitting method. These three parameters can be further revised iteratively to make the error between actual load loss and calculation load loss to be minimum. Thus the low-voltage multi-level release characteristics of the load is accurately simulated. The practical calculation case of Shanghai power grid shows that low -voltage multi-level release characteristic parameters generated by the proposed load model structure and the proposed method for determining the load model parameters, can well describe the load low-voltage multi-level release characteristics.