Equivalent Inertia Provided by Droop Control of Fast Frequency Regulation Resources

TL;DR

This paper investigates how droop control in fast frequency regulation resources can emulate inertia without causing oscillations, proposing a new strategy to provide stable, constant inertia support.

Contribution

It introduces a quantitative method to evaluate inertia from droop control and proposes a novel VDIC strategy for stable inertia provision without generator-like dynamics.

Findings

Droop control with a constant coefficient provides time-variant inertia.

The proposed VDIC strategy effectively supplies constant inertia.

Case study confirms the strategy's effectiveness.

Abstract

Conventional inertia control strategies (i.e., the VSG-based and PD-based strategies) for the fast frequency regulation resources (FFRs) might lead to system oscillations due to their emulations of generator dynamics. The only-droop-based inertia control strategy is a feasible idea to address this issue. This letter quantitatively investigates the equivalent inertia provided by the droop control of the FFRs. First, an equivalent-scenario-based method is proposed to evaluate the equivalent inertia provided by the droop control, which shows that the droop control with a constant droop coefficient provides time-variant equivalent inertia. Then, the time-variant-droop-based equivalent inertia control (VDIC) strategy is proposed for the FFRs, which can provide the required constant inertia support without introducing generator-like dynamics. A case study verifies the effectiveness of the VDIC strategy.