Voltage Regulation Strategy for Distribution Network Based on Reactive Power Compensation of Electric Vehicles

Large scale charging load of electric vehicles will increase the degree of the deviation between node voltage and nominal voltage in a local distribution network, and the deviation which caused by the charging load is random on time and place, traditional reactive compensation method can solve the above problem, but the economy is bad. So a voltage control strategy based on reactive power compensation by electric vehicles is proposed, which aims at implementing reactive power compensation for distribution network and changing the charging active power at the same time through regulating the operating power factor of the chargers effectively. The strategy can ensure the security and stability of the node voltage and the efficiency of distribution network will not decrease. A strategy is proposed to calculate the controllable scope of operating power factors of chargers after analyzing the travel behavior characteristic in a working area of first-tier/second-tier city in China and the operating characteristic of charger. Then, the node voltage regulation model is used which considers all operating power factors of chargers as variables and considers the following conditions as the optimization objective: the deviation between node voltage and nominal voltage is minimum, the variance of the node voltage from current time to all time before is minimum, the state of charge charged in at unit duration is maximum. Finally, immune algorithm is used to get the values of variables. The rationality of the proposed node voltage regulation strategy can be validated through the simulation.