Abstract: A control system for canceling load unbalance of a three-phase circuit includes phase current detectors for detecting phase currents caused to flow through a secondary circuit of a current transformer provided in high voltage distribution lines, respectively, phase change-over switches through which phases of the high voltage distribution lines, and primary sides of distribution transformers provided across high and low voltage distribution lines are connected to each other, a control center for, when a magnitude of a zero-phase current detected by the zero-phase current detector is larger than a predetermined value, on the basis of the phase currents, respectively, out putting a control signal so that the load of the phase having a maximum current appearing therein is changed over to the phase having a minimum current recognized therein, and a phase change-over slave station for controlling the phase change-over for the phase change-over switches in accordance with the control signal.

Abstract: Across current compensation control system includes a cross current detection compensator having an input terminal to which a cross connection line that cross-connects the secondary sides of auxiliary current transformers (CTs) are connected, and an output terminal to which cross current compensation lines that connect the secondary sides of CTs in series are connected, in which the cross current detection compensator supplies a compensation current to the cross current compensation line so as to cancel the current component corresponding to the cross current that appears at the secondary sides of the CTs when detecting the cross current that circulates within a bus bar, a distribution line, and a switch.

Abstract: A control system for canceling load unbalance of a three-phase circuit includes phase current detectors for detecting phase currents caused to flow through a secondary circuit of a current transformer provided in high voltage distribution lines, respectively, phase change-over switches through which phases of the high voltage distribution lines, and primary sides of distribution transformers provided across high and low voltage distribution lines are connected to each other, a control center for, when a magnitude of a zero-phase current detected by the zero-phase current detector is larger than a predetermined value, on the basis of the phase currents, respectively, out putting a control signal so that the load of the phase having a maximum current appearing therein is changed over to the phase having a minimum current recognized therein, and a phase change-over slave station for controlling the phase change-over for the phase change-over switches in accordance with the control signal.

Abstract: The system of the present invention includes transformers 12-1, 12-2 and 12-3 for detecting voltages received at a power receiving point in the power system, a negative-phase-sequence component voltage detector 18 for arithmetically operating the voltage of a negative-phase sequence component from the received voltages and amplifying the voltage of a negative-phase-sequence component to output the amplified voltage of a negative-phase-sequence component, and a negative-phase-sequence voltage compensation input unit 14 for injecting the outputted voltage of a negative-phase-sequence component into a system as an object of compensation to compensate for the received voltages at the power receiving point. The voltage of a negative-phase-sequence component is cancelled for a load 17 as an object.

Abstract: A cross current compensation control system includes a cross current detection compensator having an input terminal to which a cross connection line that cross-connects the secondary sides of auxiliary CTs are connected, and an output terminal to which cross current compensation lines that connect the secondary sides of a plurality of CTs in series are connected, in which the cross current detection compensator supplies a compensation current to the cross current compensation line so as to cancel the current component corresponding to the cross current that appears at the secondary sides of the CTs when detecting the cross current that circulates within the bus bar, the distributions and the switch.