Management of the voltage quality in the distribution system within dispersed generation sources

The paper deals with the possibilities of utilization of the distributed power generation swystems in the conditions of the Czech Republic. The influence of the dispersed generation in the medium voltage networks on voltage quality is analysed. The paper sumarises problems considered of general interest in voltage fluctuations, flicker, harmonic distortion, interharmonic distortion and the effect of the dispersed generation on ripple control signals. The influence of the dispersed generation on the voltage stabilisation, line losses and short circuits impedance is also investigated. A basic analysis of the possibility and effectinevess of using a parallel active filter to compensate reactive power and terminal voltage variation for the constant speed wind turbine flicker is presented. The modern methods of the choice of the most suitable power source for the given area are described. These sources bring new specific technical operation problems i.e. voltage level, stability in a island operation state, the quality of the power supply. The possibilities of the approaches to those tasks are mentioned in a case study. It is necessary do develop power operation and power quality management system by a communication infrastructure and optimatization tool for the distribution network operator. This device performs power quality monitoring and control and optimizes network operation through distributed generation control and demand side management. It enables integration of dispersed energy sources in distribution network at high penetration level. The main task is to use dispersed generation with renewable energy sources with minimal impact on the environment. For optimal economical and environment friendly impact it is necessary to find a compromise solution with two conflicting objectives: the minimum of the total operating costs and the minimum of the total emissions.