Research on Photovoltaic Capacity Credit Assessment and Its Impact on Power Balance in Distribution Networks

With the high penetration of grid-connected photovoltaics (PV), accurately assessing its capacity credit is crucial for ensuring reliable power system operation. This paper proposes a multi-metric cooperative assessment method for PV capacity credit based on Monte Carlo simulation, comprehensively considering reliability indices including Loss of Load Expectation (LOLE), Effective Load Carrying Capability (ELCC), and Expected Energy Not Supplied (EENS). The applicability of analytical methods and Monte Carlo simulation methods is compared, and the impact of PV capacity credibility on power and energy balance in distribution networks is systematically investigated. The research shows that as PV generation capacity increases, the reliability indices LOLE and EENS gradually decrease and eventually saturate, while ELCC progressively increases. Meanwhile, the confidence level significantly affects system operational characteristics. Although reducing the confidence level can improve voltage support capability and frequency response characteristics, it exacerbates net load ramping pressure. An increase in system LOLE will lead to higher system network loss rates. The research results can provide theoretical support for the planning and operation of distribution networks with high PV penetration, thereby enhancing PV’s support capability to the system.