Research On Substation Locating And Sizing Based On Improved Firefly Algorithm

Compared with large centralized power generation mode, distributed generation (DG) has obvious advantages. The generation mode combining large centralized power generation and DG have become an important direction of power grid construction. However, DGs connected with distribution system changes the structure of distribution network, and makes it change from single power supply network with few loops to multi power supply network with multi loops, changing the voltage condition of distribution system which causes the voltage stability problems. The paper analyses voltage stability of distribution system with high penetration of DGs.Firstly, through the study on the principle of DGs, the paper establishes the mathematical model of the various kinds of DGs, and then builds the dynamic simulation models of various kinds of DGs in the simulation software, including PV system, wind power system, fuel cell and battery. The simulations under real conditions verify the effectiveness of DG simulation model which has guiding significance for engineering practice.Secondly, on the basis of the principle and application scope of three commonly DG control modes including PQ control mode, droop control mode and V/f control mode, and studies the control strategy of micro-grid with multiple DGs based on DG control mode. Then the paper builds typical micro-grid system simulation model in the simulation software, and through the simulation analyses operation conditions of micro-grid system when connected with distribution system or in isolated operation status which verifies the feasibility and effectiveness of DGs connected distribution system through micro-grid system.Finally, based on the establishment of DGs and micro-grid system simulation models, the paper builds simulation model of distribution system in Matlab/Simulink simulation software, and analyses voltage stability of distribution system with high permeability DGs in both static and transient aspects. The main contents include: proposing static voltage stability index of distribution system, making the quantitative analysis about static voltage stability of distribution system before and after the DGs connected with the network and then discussing the impact of DGs on the static voltage stability of distribution system; through simulation analyzing the effect of penetration and fault location on transient voltage stability level when the network failure happens.