A non-superconducting fault current limiter (NSFCL).

摘要

Potential fault current levels in power grids is approaching, and may eventually exceed, the short-circuit-current limits of existing protection devices. Alternative to expensive system upgrades of protection devices, Fault Current Limiters (FCL's) provide more cost-effective solutions to prevent old protection devices and other equipment on the system from being damaged by excessive fault currents.;In this thesis, we study and review the various topologies of the emerging FCL technology, compare their advantages and limitations, and propose a Non-Superconducting Fault Current Limiter (NSFCL) topology. The NSFCL is optimized to protect against short transients and to work in conjunction with existing protection devices, hence it is simple, low-cost, and more compact than prior art. We analyze the operation of the proposed NSFCL topology under normal condition and different fault conditions, and validate the concept with simulations and experiments of a prototype on a 3-phase 600V system in a UL-certified high power lab. In the tests, the NSFCL successfully protects the system from 100kA potential fault current, by limiting the fault current to a pre-determined level of 50A.;Additionally, we analyze the stresses of the critical components under fault conditions, and specify guidelines for part sizing and parameter design for the NSFCL. Moreover, we discuss design optimizations of the proposed topology to make the NSFCL more efficient under normal conditions and smaller in size.