Commutation circuit for an HVDC circuit breaker
First Claim
1. An interrupter for interrupting a high voltage direct-current circuit which comprises a DC source having a pair of terminals, first and second electrical conductors, respectively, connected to said terminals, and a load connected across said conductors, comprising:
- a main circuit breaker connected in said first electrical conductor in series with said load and between a first one of said terminals and said load; and
a normally-open commutating circuit connected across said main circuit breaker comprising;
means for suppressing voltage surges connected across said main circuit breaker;
a snubber capacitor connected across said main circuit breaker;
a series combination including a commutation reactor and means for absorbing energy connected across said snubber capacitor;
a series combination including a commutation capacitor and an initiation switch connected across said means for absorbing energy; and
means for charging said commutation capacitor connected and maintaining said commutation capacitor precharged during normal closed contact operation of said main breaker.
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Abstract
A commutation circuit for a high voltage DC circuit breaker incorporates a resistor capacitor combination and a charging circuit connected to the main breaker, such that a commutating capacitor is discharged in opposition to the load current to force the current in an arc after breaker opening to zero to facilitate arc interruption. In a particular embodiment, a normally open commutating circuit is connected across the contacts of a main DC circuit breaker to absorb the inductive system energy trapped by breaker opening and to limit recovery voltages to a level tolerable by the commutating circuit components.
45 Citations
20 Claims
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1. An interrupter for interrupting a high voltage direct-current circuit which comprises a DC source having a pair of terminals, first and second electrical conductors, respectively, connected to said terminals, and a load connected across said conductors, comprising:
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a main circuit breaker connected in said first electrical conductor in series with said load and between a first one of said terminals and said load; and a normally-open commutating circuit connected across said main circuit breaker comprising; means for suppressing voltage surges connected across said main circuit breaker; a snubber capacitor connected across said main circuit breaker; a series combination including a commutation reactor and means for absorbing energy connected across said snubber capacitor; a series combination including a commutation capacitor and an initiation switch connected across said means for absorbing energy; and means for charging said commutation capacitor connected and maintaining said commutation capacitor precharged during normal closed contact operation of said main breaker. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A commutation circuit for a high voltage direct current circuit, wherein said high voltage direct current circuit comprises a DC source having a pair of terminals, first and second electrical conductors, respectively, connected to said terminals and a load connected across said conductors, and a main circuit breaker connected in said first conductor in series with said load and between a first one of said terminals and said load;
- said commutation circuit comprising;
a first commutation reactor connected in series with said main circuit breaker; a snubber capacitor connected across said main circuit breaker; means for suppressing voltage surges connected across said main circuit breaker; means for absorbing energy of the circuit at main breaker opening connected across the series combination of said main circuit breaker and said commutation reactor; a series combination of an initiation switch and a commutation capacitor connected across said series combination of said main circuit breaker and said commutation reactor; and means to precharge said commutation capacitor from the circuit voltage. - View Dependent Claims (8, 9, 10, 11)
- said commutation circuit comprising;
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12. An interrupter for interrupting a high voltage direct current circuit which comprises a DC source having a pair of terminals, first and second electrical conductors, respectively, connected to said terminals, and a load connected across said conductors, comprising:
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a series combination of a main circuit breaker and a commutation reactor connected in one of said electrical conductors; a snubber capacitor connected across said main circuit breaker; means for suppressing voltage surges connected across said main circuit breaker; means for absorbing energy of the circuit at main breaker opening connected across the series combination of said main circuit breaker and said commutation reactor; a series combination of an initiation switch and a commutation capacitor connected across said series combination of said means for absorbing energy; and means for charging said commutation capacitor. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A method of high voltage direct current circuit interruption comprising the steps of:
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precharging a commutation capacitor connected to a main DC circuit breaker connected in a high voltage DC circuit; opening the contacts of said main DC circuit breaker; blocking voltage surges across said breaker; blocking voltage surges across said commutation capacitor; superimposing a commutation current on the current of said breaker by discharging said commutation capacitor; and absorbing the energy of the circuit being interrupted. - View Dependent Claims (20)
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Specification