Fundamental study on voltage stability in power system with large penetration of photovoltaic generation considering induction motor dynamics

Because of global warming, the attention to the photovoltaic generation has increased, and a lot of photovoltaic generations will be installed in the power system. In Japan, most photovoltaic generations will be connected to the distribution system. This will make the power flow in the power system changed. That is to say that the forward power flow (flow from higher voltage system to lower voltage system) reduces, or, moreover, that the reverse power flow occurs. Because of the change in power flow, the voltage characteristics will be also changed. Consequently, it is expected that the penetration of photovoltaic generation has some impacts on voltage stability. In previous study, the voltage characteristics in simple power system model which consists of one infinite bus, one load, and one photovoltaic generation is made clear. It is indicated from the results that there is not only forward power flow limit but also reverse power flow limit (left nose in PV curve), and that, when the output power from photovoltaic generation is very large, left nose sometimes has some impacts on voltage stability. In this paper, the voltage stability in the simple power system model considering the dynamics of an induction motor is discussed. © 2014 The Institute of Electrical Engineers of Japan.