Multiscale power fluctuation evaluation of a hydro-wind-photovoltaic system

The hybrid energy systems are required to operate stably in different time scales. Previous studies on the stability are carried out under the unrealistic assumption of discontinuous time scales. Therefore, a second time scale model for the hybrid energy systems is presented in this study. To overcome the possible uncertainty caused by the discontinuous time scale assumption, a new method is introduced to analyze power fluctuations for the hybrid power system considering the hydroelectric power station (HPS) and PV-wind complementarity. Compared with traditional statistics, the proposed three indices, discussed in terms of variation frequency, have the ability to show the stability and complementarity characteristics of the hybrid system with the time scale varying from second to hour, The results show that the volatility of wind power and photoelectric increase with the increase of time scale. In (10 ⁰, 10 ²) seconds, the HPS could not compensate for as they do not meet flexibility demand in that particular frequency domain, and hydro-electric power is able to compensate wind and PV power sources well when the time scale is over 10 ² s. The obtained stability evolution law has important reference significance for the subsequent studies on the stability of hybrid energy systems.