Interface arrangement between AC and DC systems using grounding switch
First Claim
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1. An interface arrangement for connection between an AC system and a DC system and comprising:
- a voltage source converter for conversion between AC and DC, said converter having a DC side for connection to said DC system and an AC side for being coupled to said AC system;
a set of circuit breakers coupled between the AC side of the converter and the AC system; and
a breaker assisting unit comprising a set of branches connected between the AC side of the converter and ground, where each branch includes a switch in series with an impedance element,wherein the circuit breakers are closed and the switches are open in normal operation, andthe interface arrangement further comprises a control unit configured to close the switches of the branches upon the occurrence of a fault for ensuring zero-crossings in currents flowing through the circuit breakers and to open the circuit breakers at such zero-crossings.
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Abstract
An interface arrangement for connection between an AC system and a DC system and to a method of disconnecting a DC system from an AC system are disclosed. The arrangement includes a converter for conversion between AC and DC having a DC side for connection to the DC system and an AC side for being coupled to the AC system, a set of circuit breakers coupled between the AC side of the converter and the AC system and a breaker assisting unit including a set of branches connected between the AC side of the converter and ground, where each branch includes a switch in series with an impedance element.
22 Citations
20 Claims
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1. An interface arrangement for connection between an AC system and a DC system and comprising:
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a voltage source converter for conversion between AC and DC, said converter having a DC side for connection to said DC system and an AC side for being coupled to said AC system; a set of circuit breakers coupled between the AC side of the converter and the AC system; and a breaker assisting unit comprising a set of branches connected between the AC side of the converter and ground, where each branch includes a switch in series with an impedance element, wherein the circuit breakers are closed and the switches are open in normal operation, and the interface arrangement further comprises a control unit configured to close the switches of the branches upon the occurrence of a fault for ensuring zero-crossings in currents flowing through the circuit breakers and to open the circuit breakers at such zero-crossings. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 15, 16, 17, 18, 19, 20)
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12. A method of disconnecting a DC system from an AC system, said DC system being coupled to the AC system via a voltage source converter for conversion between AC and DC and a set of circuit breakers and to ground via a breaker assisting unit comprising a set of branches, where each branch includes a switch in series with an impedance element, and the circuit breakers are closed and the switches are open in normal operation, the method comprising the steps of:
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obtaining an indication of a fault; closing the switches of the branches based on said indication for ensuring zero-crossings in currents flowing through the circuit breakers; and opening the circuit breakers at such zero-crossings. - View Dependent Claims (13, 14)
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Specification