Research On Distribution System Voltage Stability And Control Method

In recent years, with the improvement of economy and people's living standard, electrical equipment put forward higher requirements on voltage quality. Today, in the rapid development of the power market, voltage quality problems of distribution network are becoming increasingly prominent. On the one hand, the proportion of large number of nonlinear loads and power electronic devices is increasing in the power grid load, what make the reliability of power supply drop and cause lots of electricity consumption; on the other hand, with the development of technology, the sensitive load, for example, high-tech and precision instruments, demand on the voltage quality increasingly. Voltage quality problems not only related to the power grid, but also related to the user's interests, so it must be concerned.Through the analysis of voltage stability mechanism of the power system and MATLAB simulation, it is obtained the different load models corresponding to voltage stability recovery circumstances when the fault occurs.According to voltage stability problem of distribution network, a variety of methods to improve the voltage quality are proposed, for example, reactive power compensation, change transformer's tapping switch, adopt dynamic voltage regulator for the sensitive load, according to the frequency/voltage cutting load technology, and so on. And all the methods are analyzed. The analysis aiming at method for low-voltage distribution network, especially reactive power compensation of rural network, which is scattered compensation along the way. The influence of different compensation points on power loss and voltage distribution is analyzed, and distribution switching mode of scattered compensation is researched. In addition, for the existing voltage drop problem in distribution network, the research on principles of dynamic voltage scaling devices to improve the voltage drop is studied.For the problems that exist in the power supply of Inner Mongolia Chifeng district, a specific program used to improve the reactive power voltage of the area is proposed, and the project is applied practically in pilot areas, it works well. Also, it has a sensitive load enterprise at the end of the supply area. Voltage drop phenomenon occurred several times in the thunderstorm season, it has seriously affected the normal production of the enterprise. In such cases, a program of dynamic voltage compensator (DVR) device to solve the voltage drop is proposed, and the program is implemented in the enterprise. After the installation of the device, voltage compensation realized successfully at a voltage drop, the compensation effect is obvious.Through the implementation of the program, it achieve reactive power optimization of the whole rural network in supply area of Chifeng, while it also take into account the requirements of special business on voltage quality.