A Research Of An Improved Compensation Strategy In Dynamic Voltage Restorer

With the improvement of the life, people pay more attention to the security issues which have being become more demanding, and in the 21 st century, the power industry has become one of the security risks. In the power quality problems, the voltage drop is the most frequent security problems. In the now current practice, there are three kinds of methods :use of transformer taps, the installation of fixed capacitors in parallel, synchronous condenser and other regulating methods. Generally speaking, these methods have frequent operation, easy to damage, pressure regulating means and unsuitable for the safe operation of the petrochemical enterprise requirements. Dynamic Voltage Restorer(Dynamic Voltage Restorer DVR) can be response to compensate for the voltage drop within 20 ms, more stable and faster. So DVR is an important device to eliminate the voltage drop.In this paper, the energy compensation strategy for the existing problems of the DVR to carry out research, the improved time optimization strategy will be applied to this design and improve the time when the DVR working for the system, and use the time to improve the optimization strategy to determine the installed capacity, the main research reads as follows:(1) Firstly, this paper introduces the basic principle of the DVR and the compensation process related technologies, analyzes the works of several common compensation policies;(2) This paper compares of four basic working principle of compensation strategies and their respective advantages, namely full voltage compensation strategy, with phase compensation policies and minimum energy compensation strategy and time optimization compensation strategy, compensation strategy to optimize conventional time to do a thorough research, deduced time optimization strategy implementation process, proved the advantages of this strategy in terms of time optimization, and proposed the concept of residual energy;(3) By analyzing the process of running the compensation strategy, results in different compensation strategies in different residual energy when the compensation stops power. The more that the size of the offset voltage is larger, the need to maintain this voltage energy.Compared with phase compensation, compensation time optimization, the smallest of the three energy compensation. Energy minimum energy compensation greatest legacy, time optimization, followed with a minimum phase compensation. For the remainder of this article proposing a different time and improved energy optimization strategy, optimization strategy in DVR use of time, it can not compensate for the remaining supply of energy to this time can still provide the same phase compensation method to extend energy compensation time;(4) Two important factors in determining the compensation effect of the DVR is the length and size of the offset voltage compensation at the same time supply conditions. On the contrary, we use the improved time optimization strategies in order to compensate for a certain time under the conditions to obtain compensation capacity of DVR;(5)The improve time optimization compensation strategies will be used in the dynamic voltage restorer system, and simulation in PSASP. Simulation results show that compared with the minimum energy compensation strategy and in-phase compensation strategy and the compensation, the improved optimization strategies have more compensate time; On the level of this voltage grade requirements, DVR installation capacity can be suitable.Through this study show that the improved time to optimize the DVR compensation strategy can be well compensated system voltage drop in the compensation process to find a balance between dynamic voltage restorer active power consumption and output voltage,extending the effective compensation of DVR time.