Protection device and method for distributed energy resources in electric distribution system

摘要

According to an embodiment of the present invention, provided is a protection device for connection with distributed power generators, comprising: a measurement unit configured to collect information on a voltage, a current, a frequency, a phase, and active power of a low or high voltage side connected with a distributed generator (DG); a calculation unit configured to calculate a change in the frequency, a change in the voltage, a change in the phase, and total harmonic distortion (THD); and a determination unit configured to determine that the DG is in an islanding condition if at least one of the changes in the frequency, voltage, phase, and/or the THD exceeds a maximum set value, and determine that the DG is in an islanding-suspected condition if at least one of the changes in the frequency, voltage, phase, and/or the THD is less than or equal to the maximum set value for each and exceeds a minimum set value.