Abstract: The present disclosure relates to an over-voltage prevention apparatus and method of a distribution line connected with a distributed generator, which sets a range of a dispatched voltage based on a current voltage of a Pole Mounted Automatic Voltage Regulator (PVR) and a voltage at a connection point of a distributed generator to control so that the dispatched voltage is output within the corresponding range.

Abstract: The present disclosure relates to an over-voltage prevention apparatus and method of a distribution line connected with a distributed generator, which sets a range of a dispatched voltage based on a current voltage of a Pole Mounted Automatic Voltage Regulator (PVR) and a voltage at a connection point of a distributed generator to control so that the dispatched voltage is output within the corresponding range.

Abstract: Disclosed in a stand-alone micro-grid autonomous control system including: at least one battery system directly changing a reference frequency thereof according to a charge amount, and providing power having the changed reference frequency; at least one power generator measuring the reference frequency from the power provided form the at least one battery system, and starting generating power or stopping generating power based on the measured reference frequency; and at least one load measuring the reference frequency from the power provided from the battery system, and performing a synchronization operation or a synchronization releasing operation based on the measured reference frequency.

Abstract: Disclosed in a stand-alone micro-grid autonomous control system including: at least one battery system directly changing a reference frequency thereof according to a charge amount, and providing power having the changed reference frequency; at least one power generator measuring the reference frequency from the power provided form the at least one battery system, and starting generating power or stopping generating power based on the measured reference frequency; and at least one load measuring the reference frequency from the power provided from the battery system, and performing a synchronization operation or a synchronization releasing operation based on the measured reference frequency.

Abstract: An apparatus for operating a distributed generator in connection with a power system includes an input unit which receives a parameter calculated using power system information and a voltage and a current at a point of common coupling with the distributed generator, with which the distributed generator is connected, a calculation unit which calculates an operating power factor instruction value and an active output instruction value using the parameter and the voltage and current at the point of common coupling with the distributed generator input to the input unit, and a control communication unit which determines and transmits the operating power factor instruction value and the active output instruction value according to the voltage at the point of common coupling with the distributed generator input to the input unit and an admissible voltage upper limit at the point of common coupling with the distributed generator to the distributed generator.

Abstract: An apparatus for operating a distributed generator in connection with a power system includes an input unit which receives a parameter calculated using power system information and a voltage and a current at a point of common coupling with the distributed generator, with which the distributed generator is connected, a calculation unit which calculates an operating power factor instruction value and an active output instruction value using the parameter and the voltage and current at the point of common coupling with the distributed generator input to the input unit, and a control communication unit which determines and transmits the operating power factor instruction value and the active output instruction value according to the voltage at the point of common coupling with the distributed generator input to the input unit and an admissible voltage upper limit at the point of common coupling with the distributed generator to the distributed generator.

Abstract: A control method for preventing malfunction of an over current ground relay is disclosed. The control method includes: determining directions of per-phase power flows by measuring the magnitudes and phases of per-phase voltages and currents in an electric power system; checking occurrence of a load fault or a power source fault using the determined directions of per-phase power flows; and controlling an over current ground relay (OCGR) or an over current relay (OCR) to transmit a trip signal to a circuit breaker, after, upon occurrence of a load fault, checking occurrence of a ground fault and checking occurrence of a short circuit fault, and, upon occurrence of a power source fault, checking occurrence of a short circuit fault without checking occurrence of a ground fault, by turning on or off the OCGR or the OCR according to occurrence of a ground fault or a short circuit fault.