Forecast of power generation for grid-connected photovoltaic system based on grey model and Markov chain

With grid-connected photovoltaic system increasing, distributed generations will influence the power quality. The forecast of distributed generations (e.g. grid-connected photovoltaic system) will be helpful to the planning, operations and management of distributed system. Basing on the Grey forecast GM (l, l) model and the stochastic processes Markov model, the deviation results of grey GM (l, l) model was used as the deviation transfer probability matrix of Markov model forecast. In order to increase the forecast reliability, the calculation result of GM (l, l) model was modified and limited in a forecast range which consisted of the interval and probability. The application results of grey-Markov model have greatly enhanced the accuracy of forecasts and reflected the trend of the solar photovoltaic generations when the forecast results was expressed as the forecast range instead of a value.