The Research On The Composite Load Model Structure Of Power System

The power system simulation is very important in the analyzing,programming, designing and operating of power system. The accurate degree relate to the security and stability operating of power system. Because the power system load has the characteristics of randomicity, distributivity, multiformity, the load modeling is very difficult, and the load model is not mature.In the studies of power system load modeling, model structure is one of the basal and important problem. This paper studied the two aspects of model structure. One is mechanism model, the author instruct a new"Synthesis induction-motor model"to describe power system composite load. The other is non-mechanism model, which is divided into two parts: one is neural network composite load model, and the other is parallel difference equations composite load model.The mechanism model is the most extensive load model used in transient simulation of power system, so it's necessary to study in-depth. This paper instruct a new"Synthesis induction-motor model"to describe power system composite load. In this model, the distribution network is equivalent to a set of lumping line and transformer, and the influence of OLTC and transient reactive power compensation are considered. Which is more accurate than traditional inductor model.Experiments were carried out to test this model ,some data samples from substation are used in modeling.The result shows that the model has strong desription of the power system composite load, and the model has good identifiability and generalization , whose composite capability is better than tradtional motor model.ANN is suitable for any nonlinear cure fitting at any precision theroetically and occupies simple structure. So it is widely used as the model of power composite load in past load modeling research.Through the in-depth analysis, the author points out that BP ANN is not suitable for describing the dynamic characteristics of power system composite load.This paper constructed a Elman neural network to model the power system composite load, and based on the study of neural network, the author combined the advantages of traditional difference equation and neural network, and presented a new parallel difference equation, which has good ability of description as difference equation and good ability of together calculation as neural network. The modeling instance to field measured data of power transformer substation shows that the three models presented by author can effectively describe the power system composite load characteristics and the composite load model with excellent performance.