Dynamic State Estimation-Based Protection for Induction Motor Loads

TL;DR

This paper explores the application of dynamic state estimation (DSE) for protecting load buses with induction motors in microgrids, addressing challenges posed by inverter-interfaced generation and dynamic loads.

Contribution

It introduces a novel approach using DSE to protect induction motor loads, expanding beyond passive loads previously studied.

Findings

DSE can effectively detect faults in induction motor loads.

The method improves microgrid resilience during faults.

Traditional protection methods are inadequate for inverter-interfaced loads.

Abstract

Ensuring protective device coordination is critical to maintain the resilience and improve the reliability of large microgrids. Inverter-interfaced generation, however, poses significant challenges when designing protection systems. Traditional time-overcurrent protective devices are unsuitable on account of the lack of fault current. Present industry practice is to force all inverters to shut down during faults, which prevents large microgrids from operating in a resilient and reliable manner. Dynamic state estimation (DSE) has been proposed for line protection, and more recently for the protection of load buses or downstream radial portions of microgrids. However, only passive loads with series resistive-inductive loads have been tested with DSE, even though the behavior of dynamic loads -- such as induction motors or power electronics -- may differ significantly during faults. This paper considers the case of applying DSE to protecting a load bus serving a three-phase induction motor.