Decentralized transfer of contingency reserve: Concept, benefit assessment, impacting factors, and benefit mechanism

Abstract With increasing renewable energy penetration and large capacity DC operation, there is a severe shortage of contingency reserve in the power system, which leads to the reduction of unit operational efficiency. In this paper, the concept of decentralized transfer of contingency reserve (DTCR) is firstly proposed. DTCR refers to the transfer of partial centralized contingency reserve from supply side to demand side for optimal decentralized distribution of contingency reserves in the overall system. DTCR scheme can enlarge the operation space of units and optimize the allocation of resources. Then, the benefit assessment model of DTCR is established, considering the impact of wind generators and demand response. Moreover, several important impacting factors on DTCR benefits are analyzed visually and mathematically. Thus, the diminishing marginal benefit (DMB) is found as an essential reference to select a suitable decentralized reserve capacity. The economic load rate threshold (ELRT) can be used to assess the degree of DTCR benefit and determine the operation conditions of DTCR scheme. Besides, this paper explains the benefit mechanism of DTCR, including the reduction of grid power loss and the optimized unit generation dispatch. Finally, DTCR benefits of 4 IEEE standard systems of 57 buses to 300 buses are assessed. Results indicate the significance of DTCR and verify the theoretical analysis of impacting factors and mechanism, as well as the usefulness of DMB and ELRT. DTCR is especially applicable in the peak load period for the system with insufficient contingency reserves. The work of this paper provides a new idea for alleviating the reserve burden and improving the economics of unit operation, as well as an important reference for DTCR planning, operation, and benefit allocation in the future.