Grid-Connected Key Technical Indicators and Evaluation Methods for Multi-Type Synchronous Control Equipment

Large photovoltaic stations, wind farms and high-voltage direct current (HVDC) transmission systems are being integrated into the grid, which is causing the stability of frequency and voltage of new power systems to decline, thereby imposing high requirements on the evaluation of power grid strength in regional grids. Taking into account the indicators of stability margin of frequency and voltage, this paper builds a key technical indicator system for the system of multi-type synchronous control equipment connected to the grid, including the equivalent inertia enhancement factor, steady-state frequency deviation reduction factor, voltage stiffness and steady-state voltage deviation. Considering that the objective weighting and subjective weighting can, respectively, be achieved by the independent information entropy weighing method (IIEWM), the analytic hierarchy process method (AHPM) and the integrating principal component analysis method (PCAM), an improved layered integration weight allocation method based on IIEWM-AHPM-PCAM is proposed. Meanwhile, a multi-objective comprehensive evaluation model for power grid strength is established, and a power grid strength evaluation method is proposed to accurately evaluate the support strength of frequency and voltage of grid-connected systems including multi-type synchronous control equipment. Finally, a modified model of IEEE-39 node systems is constructed using Matlab to verify the reliability of the proposed method. The results showed that, compared to IIEWM and AHPW, a better ability to reflect the degree of data independence and volatility is possessed by the proposed method.