Meeting Utility Step Voltage Change Requirements by Providing Precise Voltage Control for a PV Plant on a Distribution Feeder

Abstract

For well over 100 years now, distribution systems have served industrial, commercial, and residential customers. The generation to serve these customers for the most part has always been from some type of centralized station power source. As renewable generation becomes more distributed in the US, becoming more like Europe, it is being added to distribution networks. Most utilities have a voltage flicker limit, which is usually set at a 2% step voltage change. Often, utilities use this step change in voltage limit to set the largest size of capacitor banks on their distribution systems, but it can also be used to size the amount of renewable generation allowed on the distribution system. The renewable generation is capped at a MW size where the sudden loss of this generation keeps voltage dip no greater than 2%. Thus, a utility’s goal is to minimize the impact of variation in or the loss of the renewable generation power output on its other customers served from the distribution system. This paper presents a method for designing and sizing a STATCOM installation on a utility distribution system such that the loss of the renewable generation will not exceed the utility’s voltage dip requirements.