Bi-level framework for coordination between thermostatically controlled loads and distribution system for flexibility

Thermostatically Controlled Loads (TCLs) are increasingly growing component of grid-interactive residential and commercial building loads. TCL's operational thermodynamics and thermal inertia of buildings make them an ideal source for demand-side flexibility. A Resistance-Capacitance (RC) model analogous to a building's thermal model is used to determine building dynamics. The model requires detailed building attributes like TCL's thermodynamics, wall heat transfers, household internal thermal mass, and heat generated and radiated internally by occupants. However, the impact of occupants' activities has generally been neglected and may lead to inaccurate flexibility assessments. Furthermore, aggregated TCLs can function as Virtual Energy Storage Systems (VESS), providing innovative and cost-effective flexibility solutions to the Distribution System Operator (DSO). However, to access TCLs flexibility at the grid level, appropriate dynamic pricing signals are beneficial. The critical challenge for DSO is to design a reasonable pricing mechanism to promote coordination with VESS while considering the privacy of all entities and operational constraints of the distribution network. In this context, the paper contributes by i) developing an improved RC model considering comprehensive building dynamics incorporating occupants' activities and ii) proposing a bi-level framework for two-level hierarchical coordination between DSO and VESS for setting up dynamic prices for VESS. The results highlight that the proposed framework provides a precise estimation of flexibility, facilitating a win-win situation for all the stakeholders.