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AssigneeGeneral Electric Company
InventorsNataniel Barbosa Vicente, Mark Fredrick Culler, Brian Patrick Lenhart, Jr., Marcelo Esteban Valdes
Estimating the term…
A circuit breaker system and method having zone selective interlock features with separate restrained and unrestrained setting capability is provided. The system and method include the transmission of a selective interlock signal from a downstream circuit breaker to an upstream circuit breaker in the event of a fault condition. The upstream circuit breaker upon receipt of this signal changes the tripping response of the second circuit breaker to a restrained mode. The circuit breakers include features enabling the user to modify and adjust both the restrained and unrestrained trip curves associated with both the restrained and unrestrained modes of operation.
A method of operating a circuit breaker system comprising:
A circuit breaker configured to be arranged in series with a downstream circuit breaker, the downstream circuit breaker having a trip curve with an I2t region and an instantaneous threshold, the circuit breaker comprising:
A circuit breaker system comprising:
A method of operating a circuit breaker system comprising:
Dependencies are inferred from the claim text.
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Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has…:…
Involving signal transmission between at least two stations: involving transmissions of switching or blocking orders
Emergency protective circuit arrangements
About 3 years 4 months of term left · ends 25 Feb 2030 (estimated)
The subject matter disclosed herein relates to a system for providing zone selective interlock between circuit breakers in an electrical distribution system. In particular, the subject matter disclosed herein relates to a system for zone selective interlock between a downstream circuit breaker and an upstream circuit breaker during instantaneous trip conditions.
Air circuit breakers are commonly used in electrical distribution systems. A typical air circuit breaker (“ACB”) comprises an assembly of components for connecting an electrical power source to a consumer of electrical power called a load. The electric circuit the circuit breaker is connected to is referred to herein as the protected electric circuit. The components are referred to as a main contact assembly. In this assembly, a main contact is typically either opened, interrupting a path for power to travel from the source to the load, or closed, providing a path for power to travel from the source to the load. The ACB will further include devices and sensors, referred to as a trip unit, capable of sensing the current flowing through to the protected circuit and comparing the magnitude of the sensed current against predetermined thresholds. The trip unit's thresholds and current magnitude trip characteristics is displayed in a graphical form, commonly referred to as a “trip curve,” which indicates to a user how long the trip unit will take to trip under any given overload condition. Upon detection of an overcurrent fault condition on the protected circuit outside of the trip curve parameters, the trip unit activates the mechanical linkages that cause the main contact assembly to open.
Downstream from the ACB, other ACBs or, one, or more smaller capacity circuit breakers, sometimes referred to as molded case circuit breakers (“MCCB's”), may be installed to further protect and isolate portions of the electrical distribution system. The MCCB's are available in multiple capacities and are often arranged in tiers or levels, with multiple MCCB's being arranged within each tier. The MCCB's, similar to the air circuit breaker, include a main contact assembly that is opened and closed via a mechanical linkage assembly. A trip unit associated with each MCCB senses current flowing through that portion of the protected circuit. Similar to the ACB, the MCCB utilizes trip curves to determine when a given condition is outside the desired parameters.
Referring now to the drawings, which are meant to be exemplary and not limiting, and wherein like elements are numbered alike:
FIG. 1 is a schematic illustration of a protected electric circuit having a system of circuit breakers in accordance with an exemplary embodiment;
FIG. 2 is a schematic illustration of a circuit breaker trip unit in accordance with an exemplary embodiment;
FIG. 1 illustrates a system of circuit breakers 20 connected to a protected electrical circuit serving loads 22 within a facility 28. An electrical power source 24, such as a utility electrical grid for example, is connected to a circuit breaker 26. Circuit breaker 26 is typically located at a service entrance for the facility 28. In a large facility, such as in the exemplary embodiment, the circuit breaker 26 is an air circuit breaker (“ACB”) having the capability and capacity for connecting to three electrical phases from the power source 24 and distributing the power to different sub-circuits within the facility. The electrical loads 22 may be any type of load, including but not limited to lighting systems, process motors, data centers, heating and ventilation systems and the like.
Downstream from ACB 26, the protected circuit branches into multiple sub-circuits 30, 32, 34. These sub-circuits may include additional electrical distribution and control equipment such as transformers 36, 38 that adapt the electrical characteristics of the supplied electrical power to have the characteristics needed by the respective loads. The transformer 38 may step-down the voltage to 120V for use by a lighting circuit for example. Each of the sub-circuits 30, 32, 34 may be further sub-divided into even more refined low tier sub-circuits 40. The sub-circuits may include further electrical control devices, including but not limited to fuses and contactors for example. It should be appreciated the number of sub-circuits and tiers of sub-circuits may be numerous and that the illustration of FIG. 1 is intended to be exemplary and not limiting.
Each tier of sub-circuits generally initiates with a circuit breaker, such as circuit breaker 42 or circuit breaker 44 for example. Each circuit breaker 44 is electrically connected to receive electrical power from the ACB 26. In the exemplary embodiment, these lower tier circuit breakers 42, 44 are molded case circuit breakers (“MCCB”). Each MCCB may be either single phase or multiphase depending on the requirements of the downstream load 22 connected the MCCB.