Definitions of power quality levels and the simplest approach for unbundled power quality services

Unbundled power quality service is paid much attention to under the circumstances of deregulation and diversification of needs of customers for quality and price of electric power. One of the features of flexible, reliable and intelligent electrical energy delivery system (FRIENDS) is the unbundled power quality service. It is required to define the power quality in order to design the hardware of quality control center (QCC) in the FRIENDS concept, which is placed in the distribution system to supply several levels of power quality to customers, because there are many aspects for power quality. This paper shows one method to define the quality of power for unbundled power quality service, assuming to supply three levels of power quality such as premium power, high quality and normal quality power. The simplest circuit of QCC for single-phase loads is also presented in this paper