Operation of combined heat and power system with hierarchical heating demand considering high wind power penetration

With the rapid increasing of wind power, wind curtailment occurs more and more frequently. The increasing Combined Heat and Power (CHP) capacities with restricted operational flexibility are one of the major influencing factors for wind power accommodation. This paper focuses on elaborate formulation of CHP units, considering the hierarchical heating demand and corresponding characteristics, in order to better reveal its operational flexibility. The hierarchical heating demand cannot be replaced among different levels, thus imposing additional constraints on the operation of CHP units. Moreover, a collaborative heat supplying mechanism is proposed. The traditional individual heat demand constraints are relaxed. Instead, the operation of a group of CHP connected into a regional heat network are co-optimized, coordinating their heat status and supply to satisfy the demand of the whole system. This mechanism could further explore the flexibility of CHP. Finally, the aforementioned formulations are integrated into a security constrained unit commitment model, and implemented for numerical analysis under high wind power penetration scenarios.