Power System P-Q Decoupled Load Flow Using Interval Method Under Uncertainty

With the establishment of power market, large-scale, interconnecting power systems are being built up step by step. At the same time, various of power plants appear, and mass of computer aided equipments are being used to collect, transmit, process and transform working parameters. All of these factors increase the uncertain features in the planning and operation of power systems. In order to overcome the weakness of the conventional way of node-by-node analysis, uncertainty analysis methods are applied to power system analysis. As the power-market reform is carrying out deeply, power systems are enlarging constantly, which makes the calculating time of uncertainty analysis catch more and more attention. This paper focuses on uncertainty analysis of load flow in large-scale power systems. The main work of this paper include as below:First of all, power system interval method of P-Q decoupled load flow is proposed to analyze uncertainties in power flow. Interval arithmetic is applied to deal with uncertainties in power flow, in which uncertainty of model parameters is described by interval and each variable in equations is replaced with interval variable. This method is an efficient and effective way to take uncertainties into consideration, which allows a rigorous estimation of the influence of either form of uncertainty and only needs one simulation.Afterwards, Monte Carlo method of P-Q decoupled load flow is proposed also, in order to compare with and verify P-Q decoupled load flow using interval arithmetic. Compared with interval method, Monte Carlo simulation has disadvantages of huge calculating quantity and long computing time. However, it calculates precisely, for what it's used to validate interval method.At last, the validity and application value of the P-Q decoupled load flow using interval method under uncertainty which has advantages of fast calculating speed and short computing time compared with Monte Carlo method, are testified by 5 node and IEEE 14 node test systems.