Renewable Energy Base Power Transmission Reliability Evaluation Method Considering Power Balance and Wind Power Output Coefficient

The application of large-capacity ultra-high voltage direct current (UHVDC) transmission greatly improves the large-scale resource allocation capability. The randomness and intermittency of renewable energy power generation often lead to power deviations of up to millions of kilowatts. This poses great challenges for the electricity consumption within the sending-end system, satisfying large-scale external transmission, and ensuring the reliability of system power supply. Based on the historical data and the wind turbine output coefficient calculated by power grid planners according to work experience, the probability that the output system coefficient calculated by historical data is greater than or less than the wind turbine output coefficient calculated by experience is analyzed. Next, the 95% confidence interval is considered to ensure that the output coefficient corresponding to more than 95% of the data point satisfies the requirements and that the corresponding wind turbine output coefficient is obtained. The change of the system power surplus caused by the empirical value and the newly obtained value of the output coefficient is calculated. Then, the power balance evaluation index is defined to characterize the judgment of power surplus by selecting a new wind turbine output coefficient. Finally, the effectiveness and adaptability of the proposed method are verified by a provincial power grid.