Trip curves and ride-through evaluation for power electronics devices in power system dynamic studies

Power electronics devices are widely used in power grid associated with loads and renewable energy resources. With increasing penetration levels of these devices, their response characteristics to short circuit events can have significant impact on power system dynamics. Power electronics devices are usually sensitive to voltage sags, they could trip off line under severe voltage disturbances. The ride through capability of these devices determines if they will remain on-line. In this paper, a generic method is proposed on how to evaluate their ride through capability through trip curves. This method is a two-step procedure: Step 1 is to create trip curve of the device; Step 2 is to conduct ride through evaluation based on the created trip curve and short circuit studies. Creating a trip curve for a particular type of power electronics devices is critical. Three case studies are demonstrated in this paper on the trip curve creation for AC variable frequency drives, DC drives and solar photovoltaic inverters based on local and international standards, power grid interconnection requirements, and manufacturer specifications. The proposed method can serve as a general guideline for the trip curve creation for power electronics devices.