Study On Dynamic Reactive Power Compensation Scheme At 10kV Distribution Transformer

The 10 kV distribution transformer is the terminal equipment which connects the power grid and the users. The power quality of its low-voltage side effects the production and life of users directly. On one side, the high reactive power fluctuation in the distribution grid can be caused by the connection of the compacted and powerful-reactive load. On the other side, the operation of sophisticated equipments has much higher request of the power quality. It can realize the purpose of high-speed and accurate reactive power compensation through the way of installing reactive power compensation device on the low-voltage side of the 10 k V distribution transformer, in which way can integrate the advantages of substation’s concentrated compensation and electrical loads compensation.Through analyzing the domestic and foreign research, and combining with the actual situation of the intelligent distributing box and the intelligent distributed transformer terminal, the author present a kind of dynamic reactive power compensation at 10 k V distribution transformer. The scheme which with double parameters control mode controls the reactive power and the power factor. The STC12C5620 AD series single chip microcomputer is its controller. The scheme take disrupt compensation after the total compensation and take the reactive power gap as the final criterion. It completes the optimal compensation and suppresses the oscillation. The State Grid Corporation of China enacts two enterprise standards which are Q/GDW614-2011 and Q/GDW615-2011 to build up a standardized transformer region. The paper accords to the standards to design the layout of the function modules. To the difference of public transformer’s load and dedicated transformer’s load, combining with the advantages and disadvantages of different connection groups, the scheme takes characteristic capacitor groupings. Meanwhile, through the method of equivalent voltage, the scheme suppresses the inrush current. On the basis of relevant laws and regulations, the scheme can compensate fully according to the capacity characteristics of the device. Its control strategy is concise and methodic to ensure accuracy. This scheme has the high utilization rate of equipments, which can solve the problem of the redundancy of the equipment and overcome the shortcoming of the complex wiring in terminals to a certain extent and improve the reliability markedly.Finally, the compensation scheme is simulated and analyzed by the MATLAB software. The accuracy and feasibility of the scheme are verified by high-precise simulation model and the secondary side voltage, current and reactive waveform of public transformer and special transformer. Meanwhile, the scheme has direct and effective compensation to distribution transformer which has a high value of application.