Stability Output Limits in Distribution System Where Two Photovoltaic Power Generation Systems are Connected

When output power from photovoltaic power generation system (PV system) to distribution system approaches the stability output limit, the power conditioning system (PCS) becomes uncontrollable. In this study, the stability output limit in the distribution system, where two PV systems are connected, were investigated. A numerical calculation method was developed to estimate the influence of the magnitude of output power and the connection location of PV systems on the stability output limit. It was assumed that a PV system (PV system1) is connected in the middle of the distribution line and the other one (PV system2) is connected to the end of that. In case that one PV system1 is connected near the end of the distribution line, the stability output limit decreases with an increase in the output power. On the other hand, if the connection location of PV power1 is closer to a distribution substation, there are conditions under which the stability output limit increase with the output power. By calculating the stability output limit according to the actual the power distribution system conditions and setting the output power of PV system, it is possible to obtain the output power conditions for stable operation of PCS.