Analyzing the Impact of Demand Response on Short-Circuit Current via a Unit Commitment Model

TL;DR

This paper investigates how demand response impacts short-circuit current levels in power systems with high renewable penetration, highlighting the importance of coordinated load management for system stability and cost efficiency.

Contribution

It introduces a novel unit commitment model incorporating demand response and short-circuit current constraints, revealing the trade-offs between cost savings and system stability.

Findings

Demand response can reduce total system costs by adjusting demand.

Improper DR coordination may lead to inadequate short-circuit currents.

Properly coordinated DR increases total costs by only 0.3%, maintaining stability.

Abstract

In low-carbon grids, system flexibility can be enhanced through mechanisms such as Demand Response (DR), enabling the efficient utilization of renewable energy. However, as Synchronous Generators (SGs) are being replaced by renewable energy sources characterized by Inverter-Based Resources (IBR), system stability is severely affected. Due to the limited overload capability of IBRs, their Short-Circuit Current (SCC) contribution is much smaller than that of SGs. As a result, protection devices may fail to trip during faults. Consequently, the remaining SGs play a key role in providing sufficient SCC. Since the commitment of SGs is closely related to system loading conditions, DR can indirectly affect their SCC provision, a relationship that has not yet been investigated in the literature. Therefore, this paper incorporates both DR and SCC constraints into a unit commitment problem and conducts case studies on an IEEE 30-bus system. The results show that although DR can reduce total costs by adjusting power demand, it may also lead to inadequate SCC levels. Nevertheless, when flexible loads are properly coordinated with SCC requirements, the total cost increases by only 0.3%, which is significantly lower than the cost of system dispatch without DR. This demonstrates that DR can facilitate stable system operation in a cost-effective manner.