Abstract: Based on the output characteristics of photovoltaic cells, this paper systematically analyzes the effects of irradiance, temperature and season on the equivalent resistance of photovoltaic power stations as well as the differences in equivalent resistance under different capacities. At a constant irradiance of 1 000 W/m², the equivalent resistance of the photovoltaic power station decreases from 4.67 Ω to 3.25 Ω when the temperature rises from 0℃ to 30℃, indicating that the equivalent resistance of photovoltaic modules is negatively correlated with temperature. When the irradiance increases from 20 W/m² to 1 000 W/m², the equivalent resistance drops sharply from 121.00 Ω to 3.98 Ω at a constant temperature of 25℃, showing that the equivalent resistance is also negatively correlated with irradiance. Seasonal variations affect the equivalent resistance of photovoltaic systems, and the daily variation of equivalent resistance presents a U-shaped trend： high in the morning and evening, low at noon. The capacity of photovoltaic power stations is likewise negatively correlated with equivalent resistance： the larger the capacity, the smaller the equivalent resistance. The response trends to temperature, irradiance and seasonal changes are basically consistent. The research results provide a reference for formulating refined modeling, loss evaluation and intelligent operation and maintenance strategies of photovoltaic power stations.

Key words: equivalent resistance, irradiance, temperature, season, capacity