Reclosing relay apparatus

Claim 2

Reclosing relay apparatus for reclosing a circuit breaker in an electrical power system when the circuit breaker trips in response to a fault in the electrical power system, said apparatus including a reclosing stage with two lockout circuits for reliably preventing circuit breaker pumping, and detector means for determining the trip status and reclosure status of the circuit breaker and for generating a status signal representative thereof, said reclosing stage comprising: reclosing means governed by said status signal for reclosing the circuit breaker after a first predetermined time interval measured from the initiation of a trip status of the circuit breaker as indicated by said status signal; first lockout circuit governed by said status signal for setting a first lockout signal upon reclosure of the circuit breaker as indicated by said status signal to disable said reclosing means from reclosing the circuit breaker; second lockout circuit governed by said status signal for setting a first lockout signal, independent of said first lockout circuit, to redundantly disable said reclosing means from reclosing the circuit breaker, said second lockout circuit comprising: first circuit stage governed by the status signal for generating an intermediate signal upon reclosure of the circuit breaker as indicated by said status signal; and second circuit stage governed by said intermediate signal and the status signal for setting the second lockout signal upon retrip of the circuit breaker as indicated by the combination of the status and intermediate signals; and reset means for resetting said first and second lockout signals after a second predetermined time interval measured from the initiation of said reclosure status of the circuit breaker to enable said reclosing means for reclosing the circuit breaker, said second predetermined time interval being longer than said first predetermined time interval.

Claim 3

The reclosing relay apparatus of claim 1 wherein the first circuit stage of the second lockout circuit includes: pulse means governed by the status signal for producing a pulse when the circuit breaker recloses after a trip as indicated by said status signal; and a first latch responsive to said pulse for setting the intermediate signal; and wherein the second circuit stage of the second lockout circuit includes; a second latch responsive to the combination of a set intermediate signal and the status signal indicating a retrip status of the circuit breaker to set the second lockout signal independent of the setting of the first lockout signal.

Claim 4

Reclosing relay apparatus for reclosing a circuit breaker in an electrical power system when the circuit breaker trips in response to a fault in the electrical power system, and for reliably preventing circuit breaker pumping, said reclosing relay apparatus comprising: detector means for determining the trip status and reclosure status of the circuit breaker and for generating a status signal representative thereof; a plurality of reclosing stages arranged in a predetermined operational order, each reclosing stage comprising: reclosing means operative to reclose the circuit breaker after a first predetermined time interval measured from the initiation of a trip status of the circuit breaker as indicated by said status signal; first lockout circuit operative to set a first lockout signal upon reclosure of the circuit breaker as indicated by said status signal to disable said reclosing means from reclosing the circuit breaker; and second lockout circuit operative to set a second lockout signal, independent of said first lockout circuit, to redundantly disable said reclosing means from reclosing the circuit breaker, one of said reclosing stages being an initial operational stage of said predetermined operational order, said initial operational stage includig means for activating a next stage subsequent to completion of its circuit breaker reclosure operation, other stages of said plurality also including means for activating the next stage in said predetermined operational order with each activated stage repeating the functions of the prior stage of said order; and reset means for resetting said first and second lockout signals of said plurality of reclosing stages after a second predetermined time measured from the initiation of an initial reclosure status with regard to said predetermined operational order to enable said reclosing means of said plurality of reclosing stages for reclosing the circuit breaker, said second predetermined time interval being longer than said first predetermined time interval.

Claim 5

Reclosing relay apparatus for reclosing a circuit breaker in an electrical power system when the circuit breaker trips in response to a fault in the electrical power system, and for reliably preventing circuit breaker pumping, said reclosing relay apparatus comprising: detector means for determining the trip status and reclosure status of the circuit breaker and for generating a status signal representative thereof; a plurality of reclosing stages arranged in a predetermined operational order, each reclosing stage comprising: reclosing means operative to reclose the circuit breaker after a first predetermined time interval measured from the initiation of a trip status of the circuit breaker as indicated by said status signal; first lockout circuit operative to set a first lockout signal upon reclosure of the circuit breaker as indicated by said status signal to disable said reclosing means from reclosing the circuit breaker; and second lockout circuit operative to set a second lockout signal, independent of said first lockout circuit, to redundantly disable said reclosing means from reclosing the circuit breaker, one of said reclosing stages being an initial operational stage of said predetermined operational order, said initial operational stage includig means for activating a next stage subsequent to completion of its circuit breaker reclosure operation, other stages of said plurality also including means for activating the next stage in said predetermined operational order with each activated stage repeating the functions of the prior stage of said order; and reset means for resetting said first and second lockout signals of said plurality of reclosing stages after a second predetermined time measured from the initiation of an initial reclosure status with regard to said predetermined operational order to enable said reclosing means of said plurality of reclosing stages for reclosing the circuit breaker, said second predetermined time interval being longer than said first predetermined time interval.

Claim 6

A single reclosing relay stage including: means for reclosing a circuit breaker in an electrical power system when the circuit breaker trips in response to a fault in the electrical power system, and a first lockout circuit for locking out said reclosing means from reclosing the circuit breaker after a predetermined number of reclosures if the circuit breaker then trips before a reset timer times out; wherein the improvement comprises: second lockout circuit for redundantly locking out said reclosing means from reclosing the circuit breaker independent of said first lockout circuit, said second lockout circuit including: a first circuit stage which is set when the circuit breaker recloses on said predetermined number of reclosures; and a second circuit stage which is set when the circuit breaker trips and said first circuit stage is set, said reclosing means being redundantly locked out during the time that said second circuit stage is set, said first and second circuit stages being reset upon said reset timer timing out.

Claim 7

A single reclosing relay stage including: means for reclosing a circuit breaker in an electrical power system when the circuit breaker trips in response to a fault in the electrical power system, and a first lockout circuit for locking out said reclosing means from reclosing the circuit breaker after a predetermined number of reclosures if the circuit breaker then trips before a reset timer times out; wherein the improvement comprises: second lockout circuit for redundantly locking out said reclosing means from reclosing the circuit breaker independent of said first lockout circuit, said second lockout circuit including: a first circuit stage which is set when the circuit breaker recloses on said predetermined number of reclosures; and a second circuit stage which is set when the circuit breaker trips and said first circuit stage is set, said reclosing means being redundantly locked out during the time that said second circuit stage is set, said first and second circuit stages being reset upon said reset timer timing out.