Pricing of Short Circuit Current in High IBR-Penetrated System

TL;DR

This paper tackles the decline of short-circuit current ($I_{sc}$) in grids with high inverter-based resource (IBR) penetration by proposing a market-based SCC pricing mechanism. It embeds a linearized SCC constraint into the Unit Commitment problem and derives shadow prices using three pricing schemes: Dispatchable, Restricted, and Marginal Unit Pricing, each handling the nonconvexity of SCC constraints differently. A data-driven linearization, validated on a modified IEEE 39-bus system, enables location-specific SCC pricing and reveals that Dispatchable and Marginal Unit Pricing yield meaningful SCC values, while Restricted Pricing may be unsuitable due to non-binding constraints and potential side payments. The work provides a pathway to incentivize SCC provision at critical locations, contributing to the design of future stability service markets in high-IBR environments.

Abstract

With the growing penetration of Inverter-Based Resources (IBRs) in power systems, stability service markets have emerged to incentivize technologies that ensure power system stability and reliability. Among the various challenges faced in power system operation and stability, a prominent issue raised from the increasing integration of large-scale IBRs is the significant reduction of the Short-Circuit Current (SCC) level in the system, which poses a considerable threat to system voltage stability and protection. Thus, a proper market mechanism to incentivize the provision of SCC as a stability service is desired. However, the pricing of this service within the future stability market has not yet been fully developed, due to the nonconvex nature of SCC constraints and the locational property of SCC. To address these problems, this work aims to explore, for the first time, a pricing model for SCC service by incorporating a linearized SCC constraint into the Unit Commitment (UC) problem, to achieve the desired SCC level and extract the shadow price for SCC through different pricing methods.

Figures (6)

• Figure 1: Modified IEEE-39 bus system.
• Figure 2: Observed and linearized SCC for IBG buses (margin $\nu$ = 1)
• Figure 3: SCC at the bus of IBR 1: constrained vs unconstrained.
• Figure 4: SCC prices at IBR buses during one-day operation.
• Figure 5: SG commitment prices for different IBRs.