| Abstract | Transactive or market-based coordination strategies have recently been proposed to control the aggregate demand of a large number of electric loads. While several operational benefits can be achieved, such as reducing the demand below distribution feeder capacity limits and providing users with flexibility to consume energy based on the price they are willing to pay, our work focuses on studying the impact of market based coordination mechanisms on load synchronization and power oscillations. We adopt the transactive energy framework and apply it to a population of thermostatically controlled loads (TCLs). We present a modified TCL switching logic that takes into account market coordination signals, alongside the natural switching conditions. Our studies suggest that several factors, in a market-based coordination mechanism, could contribute to load synchronism, including sharp changes in market prices broadcast to loads, lack of diversity in user specified bid curves, feeder limits being encountered periodically and being set too low, and the form of user bid curves. All these factors can contribute in various ways to synchronization of TCL behavior and lead to power oscillations. The case studies provide novel insights into challenges associated with market-based coordination strategies, thereby providing a basis for modifications that address those issues. |
Load Synchronization and Sustained Oscillations Induced by Transactive Control