| In recent years,the DC distribution network has become an effective way for distributed energy consumption and DC load power supply,with broad development prospects.With the large number of distributed energy resources access,coupled with the frequent changes in load power,the active power imbalance p henomenon of the DC distribution network continues to occur,and the active power imbalance is the root cause of voltage deviation,so the voltage deviation problem is common in the DC distribution network,which is one of the most important power quality indicators of the DC system.In the DC distribution network,if the voltage is high,it will cause the equipment to overvoltage,the insulation performance of the equipment and its service life will be affected,and the low voltage will cause the operation of the equipment to be blocked,affecting its normal work,so the voltage deviation of the DC distribution network is worth paying attention to.Aiming at the voltage deviation problem of DC distribution network,this paper conducts a specific analysis and gives a DC voltage deviation treatment method,and the main work results completed are as follows:(1)Aiming at the DC voltage deviation problem,the provisions of the national standard for the voltage level of the medium and low voltage distribution n etwork are given,and the allowable voltage deviation range under each voltage level is determined,the causes of the voltage deviation are analyzed,and the influence of load power change,fan output change and fan access position change on voltage deviation is verified.(2)Aiming at the problem of DC voltage deviation,the battery is selected as the energy storage device for treatment,and the optimal configuration scheme of the battery is studied.As a representative device of energy-based energy storage,the battery has a large capacity of energy storage and a long discharge time,so it is suitable for the steady-state problem of voltage deviation.With the goal of minimizing the comprehensive operating cost of the system,considering the cost of power purchase in the distribution network,the investment cost of the battery and the penalty cost of the wind turbine curtailment,the optimal configuration model of the battery in the distribution network is established,and the model is compared and verified by example.(3)For the control method of battery,this paper studies the principle of active disturbance rejection control,and proposes a double closed-loop control system with PI control for the voltage outer loop and linear active disturbance rejection control for the current inner loop.Simulation has verified that compared with the traditional PI double closed-loop control,the proposed control method has a better control effect in terms of overshoot or from the adjustment time. |
