Interconnection control of distributed generation with time-synchronized phasors

Abstract

Distributed generation (DG), such as solar-energy-based photovoltaic (PV) systems, wind generation, and other renewable resources, is a quickly growing source of energy for today's power system. These assets pose challenges to grid reliability and power quality. One critical challenge is islanding (inadvertent system separation) detection, separation, and eventual resynchronizing. Research is underway to devise best practice methods for appropriate islanding control for all load and generation conditions. Wide-area measurements such as synchrophasors provide an accurate means to detect islanding conditions by enabling precise time-synchronized measurements at diverse locations. This paper presents a real-time islanding detection system for PV-based generation that is representative of many types of DG. The system utilizes synchrophasor data collected at the PV location and elsewhere in the system to detect the islanded condition. The paper shows how synchrophasors are used to isolate the DG during such conditions. It also discusses the real-time modeling and closed-loop testing of the synchrophasor-based islanding detection system, which includes the PV-based inverter and the power distribution system. The effectiveness of the system was experimentally tested on a live power system. An evaluation is also presented for using synchrophasors to resynchronize the islanded system.