Impact of Wind Power and Photovoltaic Cell Power on Power System Stability Based on L Index

L index is proposed to assess the impact of wind power and photovoltaic cell power on system stability. L index is a voltage stability index which is based on power flow and can reflect the weak point where wind power and photovoltaic cell are connected to. Because the day trends of the two DGs are different, the impacts of stability are different. The example shows wind power system could cause voltage stability fluctuation. And the photovoltaic cell could enhance stability in strong light and high temperature in daytime.