Bidding strategy of the virtual power plant consisting of thermal loads controlled by thermostats for providing primary frequency control ancillary service

Abstract

The purpose of this article is to provide a model for the effective use of on/off loads and thermal loads controlled by thermostats (TCL) in providing primary frequency control (PFC). To this end, the mentioned loads have been aggregated in the form of a virtual power plant (VPP), allowing their cumulative capability to be offered as a bid for ancillary services. In order to determine VPP bids, a droop curve similar to the droop curve of traditional power plants has been extracted for VPP, which includes the technical limitations of VPP member loads. In formulating the VPP bidding strategy, the goal is to maximize profits and to use the capabilities of TCLs more effectively; their temperature set point is considered variable, as well as the constraint of compressor lockout, energy consumption level, device’s fire frequency and the duration of their continued response (deployment end) are incorporated in the model. The results of the model are the maximum power that can be provided to the primary frequency ancillary service market and its profit. The presented model has been simulated on a test system including 70 domestic loads in MATLAB software and checked under five different scenarios. According to the obtained results, considering the variable temperature set point for TCL leads to increasing the power of VPP by 7.33%. Moreover, considering compressor lockout constraint and increasing deployment end lead to a 22.4% and 3.54% reduction to the power of VPP respectively.