ELECTRIC POWER SYSTEMS, CONTROL SYSTEMS AND ASSOCIATED OPERATIONAL METHODS (iEdison No. 0685901-22-0033)
Distributed control architecture to engage end-use loads (GFAs) as a flexible operating resource in primary frequency resource(Grid connected and islanded) This disclosure contains multiple parts: 1) The use of GFA devices to improve primary frequency response. This is essentially load shedding during transients to prevent system collapse. A paper was published in 2018 using this concept to support networked microgrid operations, but it used static setpoints. 2) The use of a distributed control architecture, e.g. OpenFMB, to enable the updating of GFA setpoints to better align with current system conditions. Specifically, the setpoints that are appropriate for grid connected operations are not ideal for an islanded microgrids and may be again different for networked microgrid operations. This update would be on the pub/sub system and would only need to be updated when there are significant changes in system conditions. 3) Determining the appropriate setpoints for each GFA based on current system conditions. The current work is examining the determination of set point values based on the resources available to support primary frequency support, i.e., spinning reserve and fast frequency regulation from grid-forming inverters. Combining these three concepts is the entire idea. GFA devices are deployed on the system as part of normal installation. During normal grid connected system transients the GFAs can respond as was envisioned in the original GFA work. When parts of the system are islanded as one or more microgrids, the OpenFMB system collects information to determine the status of how DERs available to support primary frequency response. For systems with a lower level of resource, "more aggressive" GFA set points are selected. For stronger systems the set points are "less aggressive". The goal is to engage GFAs when needed to stabilize microgrid operations, but not to shed excessive load when necessary. A example of this would be the transition from a system with a large amount of solar PV and grid-following inverters to one with more batteries and grid-forming inverters, i.e. a microgrid going from day to night. When there is a high penetration of grid-following inverters the system will be 'weaker" and it will be desirable for the GFA to operate sooner during a transient. But when there are more grid-forming batteries such aggressive load shedding is not necessary and should be avoided. This concept adaptively changes them to reflect current system conditions.