Patent ID: 8527106
Filing Date: 2013-09-03
Classification: H02J,Y02E

Abstract:
1. A system stabilization device provided in a distribution system which, when a power system is normal, is connected to the power system, and when an abnormality occurs in the power system, is cut off from the power system, and to which a dispersed generation plant and a load are connected, the system stabilization device having a control unit, and a power converter which performs a converting action and an inverting action in accordance with a gate signal fed from the control unit, wherein when the power system is normal, the control unit determines a first active component of a system current and a first reactive component of the system current, the system current flowing from the power system into the distribution system; determines a first fluctuation component included in the first active component of the system current by a first fluctuation detection block, and uses the first fluctuation component as a first current command for the first active component; determines a second fluctuation component included in the first reactive component of the system current by a second fluctuation detection block, and uses the second fluctuation component as a second current command for the first reactive component; further determines a second active component of an alternating current output current and a second reactive component of the alternating current output current, the alternating current output current being outputted from the power converter; and outputs the gate signal for reducing a first current deviation, which is a first deviation between the first current command for the first active component and the second active component of the alternating current output current, to zero, and also reducing a second current deviation, which is a second deviation between the second current command for the first reactive component and the second reactive component of the alternating current output current, to zero, and when the abnormality occurs in the power system, the control unit determines, from a system voltage of the distribution system, a frequency signal showing a frequency of the system voltage and an amplitude signal showing an amplitude of the system voltage; determines a third fluctuation component included in the frequency signal by a third fluctuation detection block, and uses the third fluctuation component as a third current command for a third active component; determines a fourth fluctuation component included in the amplitude signal by a fourth fluctuation detection block, and uses the fourth fluctuation component as a fourth current command for a third reactive component; further determines the second active component of the alternating current output current and the second reactive component of the alternating current output current, the alternating current output current being outputted from the power converter; and outputs the gate signal for reducing a third current deviation, which is a third deviation between the third current command for the third active component and the second active component of the alternating current output current, to zero, and also reducing a fourth current deviation, which is a fourth deviation between the fourth current command for the third reactive component and the second reactive component of the alternating current output current, to zero, and when a first cut-off frequency on a high frequency side of a pass band frequency of a fluctuation detection block is set to be f