Automated power feeder restoration system and method
First Claim
1. In a power distribution system including at least a first circuit breaker that receives power from a first transformer and provides power to a first feeder section that is connected to a second feeder section by a sectionalizing switch, and a second circuit breaker that receives power from a second transformer and provides power to a third feeder section, the second and third feeder sections being interconnectable by a tie switch and the first, second, and third feeder sections providing power to respective first, second, and third loads, a method of restoring power in response to a fault on a feeder section, comprising:
- sensing an overcurrent condition that causes the first circuit breaker to undergo a first opening, a first reclosing, a subsequent opening, and a subsequent reclosing;
opening the sectionalizing switch during a time period between the first and subsequent reclosings if the sectionalizing switch senses the overcurrent condition;
if the first circuit breaker locks open after the subsequent reclosing, determining whether the sectionalizing switch opened, and if it did;
determining whether the third feeder section has a capacity to carry the second and third loads, and if it can;
modifying a trip setting of the second circuit breaker to accommodate the second and third loads plus an inrush current;
closing the tie switch to transfer the second load to the second circuit breaker; and
modifying the trip setting of the second circuit breaker to accommodate the second and third loads minus the inrush current.
1 Assignment
0 Petitions
Accused Products
Abstract
A feeder restoration method starts in response to an overcurrent fault on a feeder (22) that causes a circuit breaker (42) to trip open, reclose once, trip again, and attempt to reclose again. During the time period between the first and second reclosings, any remote sectionalizing switches (46) on the faulty feeder are opened if they have also sensed the overcurrent fault, and a substation processor (50) evaluates the status of the faulty feeder and an alternate feeder (32, 34). After the second trip of the circuit breaker, the processor verifies whether the remote sectionalizing switch was closed and a remote tie switch (40) to the alternate feeder was open. If the circuit breaker locks open, the substation processor determines whether the remote sectionalizing switch did not sense the overcurrent condition (which indicates that the fault is between the circuit breaker and the sectionalizing switch) or simply failed to open. The processor then verifies that the remote sectionalizing switch voltage is zero and opens the switch. The processor next determines whether the alternate feeder and its associated transformer (30) and circuit breaker (44) can pick up the dropped load, and if they can, the substation processor modifies the alternate circuit breaker trip current settings to accommodate the new total load plus a surge current and closes the remote tie switch to transfer the load to the alternate feeder.
106 Citations
18 Claims
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1. In a power distribution system including at least a first circuit breaker that receives power from a first transformer and provides power to a first feeder section that is connected to a second feeder section by a sectionalizing switch, and a second circuit breaker that receives power from a second transformer and provides power to a third feeder section, the second and third feeder sections being interconnectable by a tie switch and the first, second, and third feeder sections providing power to respective first, second, and third loads, a method of restoring power in response to a fault on a feeder section, comprising:
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sensing an overcurrent condition that causes the first circuit breaker to undergo a first opening, a first reclosing, a subsequent opening, and a subsequent reclosing; opening the sectionalizing switch during a time period between the first and subsequent reclosings if the sectionalizing switch senses the overcurrent condition; if the first circuit breaker locks open after the subsequent reclosing, determining whether the sectionalizing switch opened, and if it did; determining whether the third feeder section has a capacity to carry the second and third loads, and if it can; modifying a trip setting of the second circuit breaker to accommodate the second and third loads plus an inrush current; closing the tie switch to transfer the second load to the second circuit breaker; and modifying the trip setting of the second circuit breaker to accommodate the second and third loads minus the inrush current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. In a power distribution system including at least a first circuit breaker that receives power from a first transformer and provides power to a first feeder section that is connected through a sectionalizing switch to a second feeder section, and a second circuit breaker that receives power from a second transformer and provides power to multiple feeder sections through multiple sectionalizing switches, the second feeder section being interconnectable by a tie switch to one of the multiple feeder sections and the first, second, and multiple feeder sections providing power to respective first, second, and multiple loads, a method of restoring power to a load in response to a fault on a feeder section, comprising:
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sensing the fault and causing the first circuit breaker to undergo a first opening, a first reclosing, a subsequent opening, and a subsequent reclosing; opening the sectionalizing switch during a time period between the first and subsequent reclosings if the sectionalizing switch senses the overcurrent condition; if the first circuit breaker locks open after the subsequent reclosing, determining whether the sectionalizing switch opened, and if it did; determining whether the multiple feeder sections have a capacity to carry the second load in addition to the multiple loads, and if they can; modifying a trip setting of the second circuit breaker to accommodate the second and multiple loads plus an inrush current; closing the tie switch to transfer the second load to the multiple feeder sections; and modifying the trip setting of the second circuit breaker to accommodate the second and multiple loads minus the inrush current. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification