A two-step method for online parameter identification of a simplified composite load model

Load is one of the most basic parts of power systems. As power system load increases steadily and related problems like voltage stability tend to be severer, load modeling is becoming more and more important in power system stability analysis and control. However, because of load characteristics like non-linearity, randomness and time-variation, load modeling and parameter identification still remain big problems. Composite load model, made up of a static load in parallel with a dynamic load, is one of the most common load models employed in power system simulation tools in China. In this paper, an online parameter identification and modeling method for a simplified composite load model is introduced. This paper is divided into two major parts: the introduction of the simplified model and dominant parameter analysis are shown firstly, then two-step method for parameter identification is proposed. The first step is the 0+ method to identify the electrical parameters and the second step is the Multi-Layer Searching Method (MLSM) to identify the mechanical parameter. Case study demonstrates that the two-step method is accurate and fast enough for online stability analysis.