Protection Challenges in the Inter-Connection of DC-Enabled Smart Homes, Communities and Buildings
Rob Cuzner, Ph.D., Assistant Professor, Electrical Engineering
Friday, May 6th
2:00 – 2:30 pm
There are a growing number of applications that benefit from DC distribution as a means of integrating Distributed Energy Resources and Energy Storage into power delivery systems. DC interconnection of homes that can cooperatively share solar PV and energy storage is being combined with a program to renovate and find occupants for vacant homes in Milwaukee. The aim is to accelerate the adoption of renewables in urban residential neighborhoods and to use combined solar PV/batteries and smart home concepts to drive down the energy costs of low income households. DC distribution will drive down complexity and cost, improve efficiency and enable use of energy-saving smart household loads (e.g. digital equipment, LED lighting, and variable speed motors) but one of the greatest challenges is in reliable DC distribution and protection against faults.
Methodologies for DC protection that match the selectivity and discrimination of AC protective systems must be developed in order to ensure the viability of DC distribution and DC microgrids. Protective systems and interfacing power electronics must work in a coordinated fashion during all kinds of fault conditions. Also, grounding, transformer isolation and galvanic isolation of faulted parts of the system present some unique challenges. The trade-offs between “breaker-based” solutions for DC version “unit-based” solutions that take advantage of inherent capabilities of power conversion equipment are also explored. Challenges in packaging, high speed sensing and communications are also addressed. Low loss, high speed Wide Band Gap power semiconductors provide opportunities for less complex solutions.