| With the progress of technology and the improvement of people’s living quality,the traditional fossil fuels begin to reveal the drawbacks of limited reserves and endangering the environment.In this situation,renewable energy such as wind and solar energy has gradually become an effective means of improving the energy structure and easing demand for energy due to their environmentally friendly feature and abundant reserves.However,grid-connected renewable energy will cause a series of problems affecting the safe and stable operation of the power grid due to the characteristic of randomness and intermittency.The application of energy storage system provides a new idea for solving the problems caused by high penetration of renewable energy.At present,researches on energy storage configuration mainly focus on single scenario,which will result in high costs of energy storage configuration and low utilization of energy storage.Therefore,this paper presents a multi-scenario energy storage configuration method,and the main contributions are presented as follows:1.The operation and control objectives in two typical single scenarios,including smoothing power fluctuations of renewable energy and load shaving and valley filling.And then the first-order filtering method and upper and lower bound of load power method are used for the configuration of energy storage,which lays the foundation for the energy storage configuration in multiple scenarios.2.In the scenario of smoothing power fluctuations of renewable energy,method of determining expected value of fluctuation rate based on probability is proposed.The method uses probabilistic analysis and confidence method to statistically analyze the historical output data of renewable energy power,and the results obtained are targeted.3.The operation and control objectives in multiple scenarios are analyzed and the energy storage configuration methods of two single objectives are determined.As a result,the range of power and capacity of energy storage are obtained.4.The parameters influencing the cost and benefit of energy storage system and the characters of different batteries are analyzed,the vanadium redox battery has been chosen as the storage battery in this paper.What’s more,an energy storage optimization model with the goal of maximum daily net income is proposed.In the model,power and capacity of energy storage are the optimal variables.Besides,the constraints of distributed grid power flow,node voltage,SOC and charge and discharge power are all taken into consideration.Finally,the data fitting method is used to solve the model.In addition,the minimum loss of network is taken as the goal to optimize the position of energy storage,which concentrates that the optimal position of energy storage is PV side.5.A real distribution system of 35kV with 190MW of PVs and 150MW of load in average in China is taken as an example to calculate the configuration results and operation situation of energy storage.The schemes in different scenarios are compared from three aspects:cost,utilization,and network losses.The results show that compare with the sing scenario,the multi-scenario energy storage configuration proposed in this paper improve the utilization from 54.17%and 36.46%to 70.49%and decrease the annual cost by 25%as well as reduce the daily network loss by 4.67%while ensuring the realization of the target. |
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