Evaluation of Power System Stability for a Hybrid Power Plant Using Wind Speed and Cloud Distribution Forecasts

Power system stability (PSS) is the ability of a system to remain in operating equilibrium which is achieved between the electric power generation and consumption. In this paper, we evaluate PSS for a Hybrid power plant (HPP) combining thermal, wind, solar photovoltaic (PV) and, hydro power generations, in Niigata City. A new method to estimate PV power generation, based on NHK cloud distribution forecast (CDF) and land ratio settings, is also introduced. Our objective is to achieve frequency stability (FS) while reducing CO2 emission in the power generation sector. So, PSS is evaluated from the results of the frequency stability (FS) variable. 6-minutes autoregressive wind speed prediction (6ARW) support for wind power (WP). 1-hour GPV wind farm (1HWF) power is computed from the Grid Point Value (GPV) wind speed prediction data. PV power is predicted by autoregressive modelling and CDF. In accordance with the daily power curve and the prediction time, we can support thermal power generation planning. Actual data of wind and solar are measured every 10-minutes and 1-minute, respectively and the hydropower is controlled. The simulation results of the electricity frequency fluctuations are within ±0.2 Hz of the requirements of Tohoku Electric Power Network Co. Inc., for testing and evaluation days. Therefore, the proposed system supplies electricity stably while contributing to CO2 emission reduction.