A composite load model aggregation method and its equivalent error analysis

Abstract

Although load modeling techniques have been widely applied in practical power system studies, the equivalence of aggregate load models needs to be further illustrated since equivalent load models are commonly adopted to describe the overall characteristics of distributed multi-level power loads in practical scenarios. Driven by two basic aggregation steps, a general composite load model aggregation method is proposed for the first time with load network topology well considered. On this basis, detailed equivalent error analysis of load model aggregation is conducted in order to explain the possible error factors and their influence mechanisms on the equivalent accuracy. Case study results for the modified IEEE 39-bus system have validated the overall feasibility of the proposed model aggregation method and the influence of each error factor under different scenarios. Finally, practical effectiveness of the derived aggregate model is further proved with field measurements in a real-world load system. In this way, the equivalence of adopting aggregate load models can be clearly demonstrated, thus providing necessary foundation for the practical applications of composite load modeling.