Calculation Method of the Equivalent Impedance of a Distribution Network based on Power Loss

The synthesis load model (SLM) is a kind of dynamic load model that directly considers the mechanism of a distribution network. Usually, the method of parameter identification is used to obtain the key parameters of SLM. With the construction of the ubiquitous electric internet of things, it will be possible to obtain the types and power consumption of mass users in the distribution network. How to obtain the load model parameters through online statistical synthesis method is a concern. Based on this concern, this paper proposes a simple method to calculate the equivalent impedance of SLM as follows: calculate the equivalent impedance according to the consumed power of the high voltage side bus and the line loss of distribution network to avoid the tedious theoretical equivalence of the complex topology distribution network and the error caused by inaccurate line parameters of the distribution network. For equivalent motor parameters, weighted synthesis is carried out according to the active power and capacity of electric equipment. A comparison between the example and the classical method shows that the method proposed by this paper is practical and effective.

I. Introduction

The load model has a great influence on the dynamic simulation results of the quantitative model of the power system, as well as on the power flow calculation, voltage stability and other issues. Under critical conditions, the calculation results may change qualitatively [1]. If the load model is too optimistic, the safe and stable operation of the power system will be threatened. In contrast, if the load model is too pessimistic, funds will be seriously wasted. However, with the continuous development of power systems, the structure of the power grid is becoming increasingly more complex. Under different conditions, the same model may get the opposite results. Therefore, more urgent needs are put forward for load model research [2].