Heavy-Duty EV Fleets as Grid-Forming Virtual Synchronous Machines: Stability Analysis and Decentralized Market Mechanisms

Abstract

The replacement of conventional synchronous generators with low-inertia renewable energy resources threatens power system frequency stability. While Heavy-Duty Electric Vehicle (HDEV) fleets offer multi-megawatt bi-directional inverter capacity, existing Vehicle-to-Grid (V2G) schemes operate as grid-following current sources that cannot provide instantaneous synthetic inertia. This paper formulates a small-signal dynamic stability framework for depot-charged HDEV fleets operating as Grid-Forming (GFM) Virtual Synchronous Machines (VSMs). Furthermore, we design a decentralized Peer-to-Peer (P2P) inertia market that settles synthetic inertia and damping provisions while explicitly accounting for battery degradation kinetics. Real-time digital simulations demonstrate that a modified 69-bus HDEV depot fleet suppresses rate-of-change-of-frequency (RoCoF) by 64.3% during severe generation trips while yielding an average net daily operator revenue of $14.85 per vehicle above baseline peak-shaving.