Surge analysis on dispersed generation with voltage-source inverter interconnecting to power system

Dispersed generation or decentralized power systems, represented by wind turbines, photovoltaics, fuel cells and so on, is expected to become more important in the future distribution system as well as FACTS (flexible AC transmission systems) technology. However, it seems that there are few investigations on insulation scheme, grounding design and other transient analyses for such new apparatus. While control method and stability analysis for various types of inverters linked to power system have been relatively discussed, those behavior under surge invasion from power line are not clarified yet. This paper discusses surge analysis on an ideal dispersed generation system interconnecting to power system via an inverter. The present model is regarded as a simplified model for wind farm generation interconnecting to transmission line. In the dispersed generation model, a three-phase voltage-source inverter with PWM signal generation circuits and ideal GTO switches was modeled using TACS cards in EMTP simulation. Moreover, the case studies of single line-to-ground fault at the certain point on the line far from the dispersed generation source were simulated, which fault is one of the simplest cases for EMTP (electro-magnetic transients program) simulation and one of the most typical accidents for the actual application. In this paper, focusing to the transient behavior of the interconnecting inverter, surge analysis on the power system with dispersed generation is described.