Zone selective interlock for a circuit breaker system
AssigneeSiemens Energy & Automation, Inc.
InventorsMario Bilac, Charles Randall Dollar, II
Life of this patent
Estimating the term…
Abstract
A circuit breaker system 10 using electronic trip units 35. The electronic trip units 35 are coupled to a communications bus 30 whereby the electronic trip units 35 can be reconfigured, controlled, and/or monitored by a central computer 20. Further, the electronic trip units are coupled to a separate control power supply line 50 and to a zone selective interlock system 70 . The zone selective interlock system 70 is configured to provide tripping delays to circuit breakers located upstream from a detected fault.
Claims23
A circuit breaker system, comprising:
- a plurality of circuit breakers, arranged in layers, each layer being coupled to the next layer in series;
- and
- at least some of the circuit breakers including an interlock interface, the interlock interface further including,
- a first connection configured to be coupled to at least one of the circuit breakers,
- an output configured to provide an interlock signal,
- a first input configured to be coupled to the output of another interlock interface on a different layer, and
- a second input configured to be coupled to the output of another interlock interface on the same layer;
- and
- wherein the interlock interface selectively controls tripping of the circuit breaker that is coupled to the series circuit and is in the layer closest to a fault and meets a fault condition and the interlock interface selectively controls maintaining circuit breakers, coupled to the series circuit that are not in layers closest to the fault, in a closed state.
An interlock interface configured to be coupled to a circuit having a plurality of circuit breakers arranged in layers, one layer being coupled in series to another layer, comprising:
- a first connection configured to be coupled to a circuit breaker;
- an output configured to provide an interlock signal;
- a first input configured to be coupled to the output of another interlock interface on a different layer;
- and
- a second input configured to be coupled to the output of another interlock interface on the same layer,
- wherein the output provides an interlock signal if one of the following conditions occurs;
- the circuit breaker associated with the output detects a fault, the second input receives an interlock signal from another interlock interface, and the first input receives an interlock signal from another interlock interface, and wherein the interlock interfaces receiving interlock signals perform tripping delays.
A method of controlling a plurality of circuit breakers, at least some of the circuit breakers including an interlock interface, the plurality of circuit breakers being arranged in layers, each layer being coupled to subsequent layers in series and the circuit breakers furthest downstream being coupled to a load, the method comprising:
- detecting a fault in a first circuit breaker that is coupled to a load;
- delaying tripping the first circuit breaker until after a predetermined time has elapsed;
- providing an interlock signal to any other interlock interfaces on the same layer as the first circuit breaker;
- providing an interlock signal to interlock interfaces on the next upstream layer;
- delaying tripping a second circuit breaker on the next upstream layer until after a predetermined time has elapsed.
Dependencies are inferred from the claim text.