Study Of Distributed Generation Locating And Sizing Optimal Allocation Considering Power Quality

At present, with the continuous development of the electric power system, the power quality problem receives more and more attention from people. On the one hand, wide application of the power electronic technology brings relatively serious harmonic pollution to the power grid, on the other hand, voltage sags pose a growing threat to the normal operation of equipments in the electric power system. The birth of distributed generation(DG) caters to the power source need of the power grid, follows the trend of transition from the centralized power supply mode to the distributed power supply mode, and also satisfies the social desire of environmental improvement. At the same time, the access of distributed generations makes a variety of impact on the power grid, the impact changes with different DG locations, sizes and numbers. On the basis of considering the DG cost and the active power loss, this paper also takes the voltage quality and votage sag into objective function and uses harmonic limits as new constraints. By using standard particle swarm optimization(SPSO), improved particle swarm optimization(IPSO), genetic algorithm(GA) and artificial bee colony(ABC) for DG optimal configuration calculation, the DG optimal configuration schemes considering power quality have been obtained.First of all, this paper respectively sets up models of DG, transmission line, linear and non-linear loads, and also induction motor, uses back and forward sweep method based on electric current to calculate fungamental power flow, utilizes decouplong algorithm to calculate harmonic power flow and employs an algoriyhm combined with Monte Carlo method and symmetrical component method to calculate the voltage sag level of each node after short troubles, all of these provide optimization the calculation base. This paper also sets up an overall objective function considering DG cost, active power, voltage quality and voltage sag, respectively uses SPSO and IPSO for optimal configuration. By simulated analysis on IEEE33 bus test system, this paper has obtained the optimal DG locations and sizes and compared the effects on the results from different particle swarm optimizations, the final results show that the DG optimal configuration can improve the operating state of the grid.On the basis of original models, this paper sets up the parallel capacitor model, analyzes the effects of different types of parallel capacitor on grid and respectively use IPSO, GA and ABC to figure out the DG optimal configuration. By simulated analysis on IEEE33 bus test system considering parallel capacitors, this paper obtained the optimal DG locations and sizes and compared the differences of results form different methods, the final conclusions are effective and valuable as reference on solving DG locating and sizing problems.