Providing Improved Power Quality in Microgrids: Difficulties in Competing with Existing Power-Quality Solutions

Much of the microgrid literature assumes that providing improved power quality, i.e., eliminating short-duration disturbances by seamless islanding, is a fundamental objective for microgrids. however, seamless islanding adds significant cost through high energy-storage and inverter rating requirements. Power quality microgrids will face significant barriers in competing with the existing power-quality solutions due to customer perception against exposing critical loads to disturbances and the challenge of supplying a level of power quality com-parable with the existing solutions. Achieving 1/4-cycle or faster response time is difficult with the common distributed line interactive microgrid architecture because of distributed generation interfering with forced commutation of the static switch. To avoid adding unnecessary cost, three main value propositions for microgrids are identified: reliability; energy arbitrage; and power quality. Requirements and characteristics are described for microgrids designed for each of the three value propositions, and sample designs are compared for an example case.