| The energy crisis and the increasing environmental pollution in recent years have sounded a warning to human development.As an effective way to alleviate the dual problems of energy and the environment,electric vehicles have developed rapidly and the number of electric vehicles has grown dramatically.While providing opportunities for the power supply market,the security and stable operation of the power system are also facing new challenges.Therefore,effective measures need to be explored to reduce the series of adverse effects of the electric car’s access to the grid.Firstly,a load model considering the difference of status information of electric vehicles is established.Considering the difference in positivity of peak-to-valley power price response between users of electric vehicles under different SOC conditions,based on the principle of consumer psychology,the uncertainty of peak-to-valley price of electric vehicles is established.The charge-discharge optimization scheduling model aims at minimizing the difference of daily peak-valley load,taking into account the user’s discharge-benefit constraints,and adopting particle swarm optimization algorithm to solve the optimal peak-to-valley price strategy.The example analysis shows that this strategy can reduce the user’s charging cost and reduce the load peak-to-valley difference,and the demand response uncertainty model is more in line with the actual situation.To further implement the distribution network based on the peak-to-valley price-based charge-discharge optimization dispatching strategy,the load-time probabilistic model of the base load and the electric vehicle was established,and the uncertainty of the load was introduced by introducing the semi-invariant method.Solve.Using IEEE 33-bus example verification,the voltages of nodes 18,22,33 before and after ordered charging and discharging are compared with the expected values of active power of branches 5-6 in 24 period time.The results show that the ordered charge-discharge strategy can improve the charging node of electric vehicles.The problem of voltage and branch active power fluctuations is shown by comparing the semi-invariant method with Monte Carlo calculation results,and has high computational efficiency.Finally,the reliability evaluation of the distribution network which takes into account the charging and discharging optimal dispatch of electric vehicles is carried out.Based on the seasonal optimal load dispatching strategy of electric vehicles considering the seasonal characteristics of load,a seasonal load model of comprehensive load is established,and the electric vehicle connection is given.The island power supply strategy of the distribution network faults in the region during the discharge period.The reliability test of IEEE-RBTS BUS6 is used to test that the orderly charge-discharge strategy under the appropriate scale of electric vehicle access can reduce the impact of electric vehicle load on the reliability of the distribution network.This paper investigates the optimal dispatching strategy of the orderly charge and discharge of electric vehicles based on the peak-to-valley price,taking into account the uncertainty of the demand response.The implementation of this strategy could improve both the load flow and the reliability of the distribution network.A certain degree of improvement has been achieved;it has certain reference value for reducing the negative impact of electric vehicle load on the distribution network,coordinating the utilization of both sides of the network and the resources,and promoting efficient operation of the power grid. |
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