A SIMULATION OF LOAD VARIABILITY OF A SYSTEM POWER STATION CAUSED BY A MICROGRID FED BY RENEWABLES

Conventional grid systems require significant reserve capacity to manage the variability of demand, and the failure. A large power station as well as the microgrids supplied by renewable energy sources are committing to meet the power balance between generated and demanded power in the power system. In case of insufficient sun irradiation or wind speed, the electricity generation in photovoltaic and wind farms should be supported by thermal (classical and/or nuclear) power plants committing in the power system, which means that a microgrid is importing the energy. In the other case the energy is exported or stored. The possibilities of covering the varied load by system power plants are curtailed. The presented paper tackles the technical and economical effects on the cost of electricity generation in mentioned manner by system power plants and power operation with the use of characteristics described for committing power plants. Inside of a microgrid demand electricity generation management (EGM) and demand side management (DSM) should be applied. The results of simulation support the decision connected with the strategy of balancing the power flow among some microgrid with regard to plant operation in order to meet the power sytstem (PS) balance - between demanded load P-dt and generated power P-gt, in each t moment of time.