0093-9994 (c) 2018 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/TIA.2019.2911570, IEEE Transactions on Industry Applications Solid-State Fault Current Limiters for Residential Houses and Commercial Buildings David Philpott Student Member, IEEE North Carolina State University Raleigh, NC 27606, USA dphilpo@ncsu.edu Li Qi Senior Member, IEEE ABB Inc. 940 Main Campus Dr. Raleigh, NC 27606, USA lisa.qi@us.abb.com Abstract – This paper presents an overview and techno- economic feasibility study of Solid-state Fault Current Limiters (SSFCL) for low voltage residential and commercial applications. A SSFCL is proposed to be installed upstream inside a conventional panelboard or load center. The simulation results demonstrate the effectiveness of utilizing SSFCL for residential houses and commercial buildings and the advantages of fast fault current limiting and great reduction of fault energy. Some physical design considerations are made for installing a SSFCL including their fault current limiting inductors inside a panelboard or load center. The proposed SSFCL solution potentially has best overall benefits compared to the conventional mechanical solution and other solid-state based solutions. Index Terms—solid-state, fault current limiter, inductor, panelboard, load center, residential house, commercial building. I. INTRODUCTION The distribution of electricity from the utility to the consumer is essential for the operation of residential houses and commercial buildings. Panelboards and load centers are commonly used to provide protection for the power received from the utility grid to branch circuits throughout the houses or buildings. The panelboard or load center enclosure provides a platform for several different types of protection devices. Conventionally, panelboards or load centers include main circuit and branch circuit protection devices. The most widely used protection devices are fuses and mechanical circuit breakers, such as Molded Case Circuit Breakers (MCCBs) for panelboards and Miniature Circuit Breakers (MCBs) for load centers. Fuses can react to an interrupt fault fast (within a half of a cycle). However, fuses cannot be reused once a fault occurs. The mechanical circuit breaker is a robust protection solution that provides fault interruption and can be reset. Fig. 1 illustrates the layouts and connections of a conventional panelboard and a conventional load center. Three-phase 480V AC lines from a utility distribution grid go into the panelboard, where MCCBs are used to protect main input circuit and branch circuits. The single-phase lines from the panelboard can supply power to the single- or split-phase load center at 240/120V, where end loads are connected. A MCCB is optional as the main circuit breaker and several MCBs are used in the load center to provide protection to end load branch circuits. Single phase load center Three phase panelboard N A B ABC N MCCB 3ph upto 480V, 1200A MCCB 3ph 100~1200A MCCB 2ph, 240/120V 225A MCB 1ph 10~20A Fig. 1. Typical panelboards and load centers installed at residential houses and commercial buildings Some key features of the modern panelboards and load centers are: · capable of communication; · capable of remote or wireless control; · capable of monitoring and metering power or current. Communication and power monitoring are widely found in existing panelboard or load center products from different manufacturers. Remotely controlled circuit breakers can be found in the panelboards by some manufacturers. Although many commercially available circuit breakers have electronic controls, solid state circuit breakers are brand new technology and were not applied for homes and buildings. At least one manufacturer has developed a full solid-state panelboard and one example design of such a panelboard is shown as [1]. Compared to the conventional panelboards of full mechanical circuit breakers, the solid-state panelboards of full solid-state circuit breakers offer ultrafast fault current interruption and great reusability with the sacrifice of high capital cost and reduced efficiency. An alternative of the full solid-state protection solution is to use Solid-State Fault Current Limiters (SSFCLs) in panelboards or load centers. This paper will examine the concept and design of implementing SSFCLs for residential houses and commercial buildings. Section II describes different types of SSFLCs and some design issues. Simulation results are presented and analyzed in Section III. The