| CPC H02J 3/26 (2013.01) [H02J 3/18 (2013.01); H02M 7/48 (2013.01)] | 10 Claims |
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1. A zero-sequence current balancer for a controlling zero-sequence current in a three-phase power system including phase lines and a neutral conductor, comprising:
a zig-zag transformer having an input end and an output end, the input end being coupled to the phase lines of the three-phase power system;
an inverter having an input and an output, the output being connected to the neutral conductor;
a load-break switch operating as a normally closed switch and having a first terminal connected to the output end of the zig-zag transformer and a second terminal connected to the input of the inverter such that the zig-zag transformer, the load-break switch, the inverter and the neutral conductor are connected in series, wherein the load-break switch is structured and configured to carry a rated current of the inverter and to block a voltage present during a grid fault in the three-phase power system;
a clamp device operating as a normally open switch, the clamp device having a first terminal connected to the output end of the zig-zag transformer and a second terminal connected to the neutral conductor, the
clamp device being connected in parallel with the inverter; and
a controller coupled to the load-break switch, the controller being structured and configured to control operation of the load-break switch and the clamp device, the controller is also being structured and configured to do at least one of: open the load-break switch or close the clamp device based on a detection of a fault condition in the three-phase power system.
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