Impact Of Distributed Generation On The Change Of Voltage Of Distribution System

Distributed generation is often associated with the existing distribution network, therefore the study of the effect of distributed generation on original distribution system can contribute to its safe, reliable and efficient connection with the distribution network. How to join the distribution generation into the distribution network safely and reliably is directly related to the value of distributed generation. The impact of voltage of system will directly affect quality of power supply and system stability as the injection of distributed generation. Therefore, the study of the impact of voltage becomes important after the injection of distributed generation.This thesis uses hierarchical forward and backward substitution method to draw the effect of DG to the the voltage of each node of distribution network when the DG size, location and operating mode are different. In the calculation process the distributed generation is seen as "negative load" and the example is the IEEE33 bus system. Then a synchronous generator as distributed generation model is established to connect with the distribution network. A single feeder is built as the load model of distribution network. According to the size and location and power factor of distributed generation, the effects of distributed generation on distribution systems voltage is discussed and draws a conclusion. At the same time, SVC is introduced into the distribution network with distributed generation to regulate the voltage, which has been testified by the simulation results. According to the size and location and power factor of distributed generation, the influence of distributed generation on the amplitude voltage sag is summarized when the system occurre symmetrical short-circuit fault and asymmetrical short-circuit fault. Finally, the impact of distributed generation on the voltage transient of fault node when the the failure eliminate is analyzed by simulation.