Evaluation for Power Supply Reliability of Wind Power Grid-connected System Considering Energy Storage Assistance

This paper aims to evaluate the power supply reliability of wind power grid-connected systems (WPGS) considering energy storage assistance. The wind farm operating state transition model is established based on the Quasi-sequential Monte Carlo (QMC) method, by which the transition probabilities and the duration time of all wind farm operating states containing full start-up, capacity reduction and shutdown can be obtained by calculated the average values throughout a typical continuous operation of several years, thus making the results more reasonable and close to reality. Two power supply reliability indexes (PSRI) of the WPGS containing power supply insufficient probability (PSIP) and power supply quantity shortage (PSQS) are individually built up by solving the average values throughout the chosen several continuous operation years. Test verification is carried out by comprehensively comparing the power supply reliability indexes of WPGS under different operation modes containing grid-connected, off-grid and energy storage assistance. The results show that the PSIP and PSQS of the WPGS in off-grid operation mode are much higher than those in the grid-connected and energy storage assistance operation modes. The PSIP of WPGS under the grid-connected and energy storage assistance operation modes are superior enough when the grid-connected number of wind turbines reaches 35 and the wind power penetration rate reaches 56.7568%, verifying the improvement effect of energy storage device on the PSRI of WPGS and providing theoretical guidance and planning for the reliable operation of WPGS.