Improved Continuation Power Flow And Its Application In Static Voltage Stability

In recent years, along with the deregulation of the electricity market, the load is booming, so the operation of the power system is closer to its limits, voltage instability accidents are more prone to occur. Continuation Power Flow (CPF) is a core component of the static voltage stability analysis, can provide limit transmission power and voltage stability index for operators to take measures to prevent the occurrence of power system voltage instability accident. However, the existing CPF are based on the nonlinear power flow equations, resulting in slower computing, in addition, in the calculation process does not consider the effect of dynamic elements. Based on this, this paper focuses on a study of CPF and the aim of this paper is to provide a more rapid and accurate algorithm. The study includes the following aspects:(1)Summarize the principles of the existing CPF and calculation steps, analyzing why computing speed of existing CPF is slow. To improve the calculation speed of the CPF, by introducing new state variables paper proposed an improved CPF can be used for Radial distribution grid. The new algorithm reduces the calculation amount because of Jacobian matrix is fixed. In this paper, implement the traditional CPF and improved CPF with MATLAB and benchmark systems including IEEE 14-node, the U.S. PG & E 69-node distribution network systems are tested to demonstrate the efficiency and reliability of our methodology and algorithm.(2) Because the above improved method is only applicable to radiation networks, this paper further improves the CPF can be applied to the transmission network. By adding a new equation so that Jacobian matrix is fixed in the calculations, increasing the efficiency of computing. Simulation of IEEE 9-node system verify the effectiveness of improved CPF.(3)Existing static voltage stability analysis methods are based on the steady-state power flow equations, ignoring the role of the system dynamics originals, but the power system is a dynamic process. So this paper presents a dynamic voltage stability index based on PSD-FDS which takes into account the impact of simulation generator excitation limiters. Through simulation of 3-generator-10-node system, verify the power limit calculated by CPF is conservative bias. Finally, this paper analyzes the voltage stability of Liaoning Power Grid for providing a reference to operators.