Distribution Grid Reliability Analysis Considering Regulation Down Load Resources Via Micro-PMU Data

There is a growing interest by power system operators to encourage load resources to offer frequency regulation. There are several studies that evaluate the system-wide benefits of such load resource participation. However, the current literature often overlooks the potential adverse impact on power distribution feeders. This paper seems to address this open problem. We focus on a scenario where load resources offer regulation down service. We start by developing a novel data-driven approach to use distribution-level. mu PMU data to analyze transient load behaviours. Subsequently, we model the aggregate load transient profile, in form of an aggregate three-phase surge current profile, that is induced on a distribution feeder once a group of loads responds to a regulation down event. The impact of delay, e.g., due to sensing, communications, and load response, is taken into consideration. Distribution grid reliability is then analyzed based on different characteristics of typical over-current protection relay devices. Both momentary and permanent reliability indices are calculated. Case studies suggest that it is possible to jeopardize power distribution grid reliability if several regulation down load resources are on the same feeder. The probability of failure depends on the distribution grid protection system and the amount and distribution of delay in the regulation aggregation system.