Patent Application
20140118875
1. Field
This invention pertains generally to circuit interrupters and, more particularly, to configurable circuit interrupter electronic trip units and a control and monitoring unit for monitoring, displaying and/or changing conditions, parameters, settings and/or events within circuit interrupter electronic trip units.
2. Background Information
Electrical switching apparatus such as circuit interrupters and, in particular, circuit breakers of the molded case variety, are well known in the art. See, for example, U.S. Pat. No. 5,341,191.
Circuit breakers are used to protect electrical circuitry from damage due to an overcurrent condition, such as an overload condition or a relatively high level short circuit or fault condition. Molded case circuit breakers typically include a pair of separable contacts per phase. The separable contacts may be operated either manually by way of a handle disposed on the outside of the case or automatically in response to an overcurrent condition. Typically, such circuit breakers include: (i) an operating mechanism which is designed to rapidly open and close the separable contacts, and (ii) a trip unit which senses overcurrent conditions in an automatic mode of operation. Upon sensing an overcurrent condition, the trip unit trips the operating mechanism to a trip state, which moves the separable contacts to their open position.
Industrial circuit breakers often use a circuit breaker frame which houses a trip unit. See, for example, U.S. Pat. Nos. 5,910,760; and 6,144,271. The trip unit may be modular and may be replaced in order to alter the electrical properties of the circuit breaker.
It is well known to employ trip units which utilize a microprocessor to detect various types of overcurrent trip conditions and to provide various protection functions, such as, for example, a long delay trip, a short delay trip, an instantaneous trip, and/or a ground fault trip. The long delay trip function protects the load served by the protected electrical system from overloads and/or overcurrents. The short delay trip function can be used to coordinate tripping of downstream circuit breakers in a hierarchy of circuit breakers. The instantaneous trip function protects the electrical conductors to which the circuit breaker is connected from damaging overcurrent conditions, such as short circuits. As implied, the ground fault trip function protects the electrical system from faults to ground.
Each circuit breaker is designed for a specific maximum continuous current. This current rating may be set by a suitable selection mechanism, such as by a rotary switch or by selection of a resistor (e.g., a “rating plug”) which converts a current to a voltage for use by the trip unit. In some instances, a single circuit breaker frame may be easily adapted for installations which call for a range of maximum continuous currents, up to the design limits of the frame, through use of the selection mechanism by which the current rating of the device can be established. Typically, the pick-up currents for the various protection functions have been selectable multiples or fractions of this current rating. Thus, instantaneous protection trips the device any time the current reaches a selected multiple of the rated current, such as, for example, ten times the rated current. Pick-up for short delay protection is a lesser multiple of the rated current, while pick-up current for long delay protection may be a fraction of the rated current. Typically, the short delay trip is only generated when the short delay pick-up current is exceeded for a short delay time interval, although, in some applications, an inverse time function is also used for short delay protection.
Currently, many electronic trip units use adjustable (e.g., without limitation, rotary) switches to vary functional trip settings, such as, for example and without limitation, long delay pickup (Ir), long delay time (LDT), short delay pickup (SDPU), ground fault pickup (GFPU), and short delay time and ground fault time (SDT/GFT). The adjustable switches are typically labeled on a per unit basis and are common to all current sensor (e.g., current transformer) types. The Ir adjustable switch is based upon a percentage of the current sensor. For example, the Ir adjustable switch has eight positions. The lowest position represents 40% of the current sensor rating and the highest position corresponds to 100% of the current sensor rating.
Manufacturers of circuit interrupters readily seek to reduce the size and cost of circuit interrupters and electronic trip units. Hence, it is desirable to maintain the full functionality of an electronic trip unit while reducing its cost. It is also desirable to eliminate components of an electronic trip unit while also maintaining all its functions.
There is room for improvement in systems including circuit interrupter trip units.
These needs and others are met by embodiments of the disclosed concept.
In one embodiment, a circuit interrupter system is provided that includes a circuit interrupter including a processing unit and configured to run a USB stack for enabling communication with the processing unit, and a portable computing device selectively connectable to the circuit interrupter through a USB connection, the portable computing device being structured to function as a USB host and to implement a graphical user interface for enabling communication between the portable computing device and the processing unit of the circuit interrupter when the portable computing device is connected to the USB processing unit of the circuit interrupter.
In another embodiment, a circuit interrupter is provided that includes a processing unit, wherein the circuit interrupter is configured to function as a USB peripheral responsive to a portable computing device functioning as a USB host being connected to the processing unit through a USB connection to thereby enable communication between the portable computing device and the processing unit of the circuit interrupter.
In another embodiment a portable computing device is provided that is structured to be selectively connectable to a circuit interrupter through a USB connection. The portable computing device includes a display and a processor apparatus storing one or more routines executable by the processor apparatus, the one or more routines being adapted to cause the portable computing device to function as a USB host, and implement a graphical user interface displayable on the display, the graphical user interface enabling communication between the portable computing device and a processing unit of the circuit interrupter when the portable computing device is connected to the circuit interrupter.
In still another embodiment, a computer program product tangibly embodied on a computer readable medium of a portable computing device structured to be selectively connectable a circuit interrupter through a USB connection is provided, wherein the computer program product includes one or more routines executable by a processor apparatus of the portable computing device. The one or more routines are adapted to implement a graphical user interface displayable on a display of the portable computing device, the graphical user interface enabling communication between the portable computing device and a processing unit of the circuit interrupter when the portable computing device is connected to the circuit interrupter.
A full understanding of the disclosed concept can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:
Directional phrases used herein, such as, for example, left, right, front, back, top, bottom and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein.
As employed herein, the statement that two or more parts are “coupled” together shall mean that the parts are joined together either directly or joined through one or more intermediate parts.
As employed herein, the term “number” shall mean one or an integer greater than one (i.e., a plurality).
Electronic trip unit 8 also includes an internal serial port interface (SPI) 26 provided as part of the printed circuit board (PCB) electronics of electronic trip unit 8. SPI 26 is operatively coupled to microprocessor 16 to allow for serial communication with microprocessor 16. The PCB electronics of electronic trip unit 8 further includes USB microprocessor 28, which is an integrated circuit chip that is configured to run a USB stack. USB microprocessor 28 running the USB stack allows electronic trip unit 8 to connect with a USB host (e.g., computing device 10 described elsewhere herein) and plug and play communicate with the USB host. The USB stack is usually supplied by the chip vendor at no additional cost. USB microprocessor 28 also has an on-board serial port interface (SPI) (as well as a Universal Asynchronous Receiver/Transmitter (UART) for translating data between parallel and serial forms). The on-board SPI enables communication with SPI 26 and thus provides for communication between USB microprocessor 28 and microprocessor 16. In addition, that same configuration thus allows for a device coupled to USB connector 14 (e.g., computing device 10) to communicate with microprocessor 16 through SPI 26 and USB microprocessor 28.
An exemplary portable computing device 10 that may be used in system 2 is depicted schematically in
Processor apparatus 34 comprises a microprocessor (μP) 38 (or other suitable processing device) and a memory 40 that interfaces with microprocessor 38. Memory 40 can be any one or more of a variety of types of internal and/or external storage media such as, without limitation, RAM, ROM, EPROM(s), EEPROM(s), FLASH, and the like that provide a storage register, i.e., a machine readable medium, for data storage such as in the fashion of an internal storage area of a computer, and can be volatile memory or nonvolatile memory. Memory 40 has a number of routines stored therein that are executable by microprocessor 38. One or more of the routines implement (by way of computer/processor executable instructions) a graphical user interface (GUI) software application 42 that is described in greater detail below and that is configured to, among other things, enable a user to monitor, display and/or change conditions, parameters, settings and/or events within circuit interrupter 4 (graphical user interface (GUI) software application 42 thus comprises a computer program product tangibly embodied on a computer readable medium of the portable computing device 10). Another one or more of the routines comprise a USB host stack 44 that enables computing device 10 to function as a USB host and, on a plug-and-play basis, communicate with USB peripheral devices (e.g., HIDs) through USB connector 36. Thus, according to an aspect of the present invention, computing device 10 is able to function as a USB host and be connected to trip unit 8 using USB cable 12 (
Referring to
As is known in the art, Zone Selective Interlocking (ZSI) is an optional method that provides a wired method of coordinating upstream and downstream breakers. Typically, the coordinating signals are provided by the White\Red stripe (Zin), White\Black stripe (Zout), and Black (common ground) wires that exit the right side of the typical breaker. A typical connection (two breaker system) is accomplished by connecting the Zout wire of the downstream breaker to the Zin of the upstream breaker. The common black wires of both breakers must also be connected. If a high current fault is sensed from the load on the downstream breaker, both breakers will sense the fault. However, the downstream breaker will send the interlock signal to the upstream breaker, informing it not to trip as defined by the SD time settings of both breakers. This delay allows the downstream breaker to clear the fault without the upstream breaker tripping. However, if for some reason the downstream breaker does not clear the fault in the set delay time, the upstream breaker will then clear the fault. The ZSI option is enabled in firmware in the trip of a typical breaker.
According to a further aspect of the present invention, GUI 42 enables a user to easily enable and disable the ZSI option of electronic trip unit 8 when computing device 10 is coupled to electronic trip unit 8 using the USB connection. Thus, as seen in
As is known in the art, Remote Maintenance Mode is a safety option that allows a breaker to be remotely placed in the lowest pickup setting and the fastest time setting. This greatly reduces the destructive energy of the breaker under fault conditions and protects people that are standing directly in front of the breaker performing breaker maintenance. Typically, the Remote Maintenance Mode is enabled through an analog relay by applying 24VDC to the two wire cable that exits the left side of the breaker.
According to a further aspect of the present invention, GUI 42 enables a user to easily enable and disable the Remote Maintenance Mode of electronic trip unit 8 when computing device 10 is coupled to electronic trip unit 8 using the USB connection. Thus, as seen in
In addition, many breakers have an over temperature protection set point that protects the breaker from operating in ambient temperatures above the set point. (standard protection is typically set at 85 degrees C.). If the set point is exceeded, the breaker will trip.
According to a further aspect of the present invention, GUI 42 gives a user the ability to read the ambient temperature (as sensed by a temperature e sensor coupled microprocessor 16) within circuit interrupter 4 and change the over temperature set point (e.g., over the allowable range of 85 degree C. to 105 degree C.) when computing device 10 is coupled to electronic trip unit 8 using the USB connection. Thus, as seen in
As described elsewhere herein, ADC 18 of electronic trip unit 8 is structured to receive a number of current signals indicating the current of each phase of the system to which circuit interrupter 4 is connected, and convert those signals to digital data that is appropriate for microprocessor 16. According to a further aspect of the present invention, GUI 42 gives a user the ability to read and compare the current of each phase of the system to which circuit interrupter 4 is connected when computing device 10 is coupled to electronic trip unit 8 using the USB connection. Thus, as seen in
In certain breakers, if the breaker trips, a cause of trip is stored (e.g., in the RAM 20 of electronic trip circuit 8). According to a further aspect of the present invention, GUI 42 gives a user the ability to read and display the cause of trip of circuit interrupter 4 when computing device 10 is coupled to electronic trip unit 8 using the USB connection. Thus, as seen in
Selective coordination allows a system of breakers to be prioritized by varying the current pickup and trip times (such as, for example and without limitation, long delay pickup (Ir), long delay time (LDT), short delay pickup (SDPU), and short delay time (SDT)). Usually, the downstream breakers are programmed to trip in the shortest time, and the upstream breakers will trip only if the downstream breakers fail to trip on a fault. In one aspect, selective coordination may be performed on a number of circuit interrupters 4 by sequentially connecting computing device 10 to each electronic trip unit 8 using the USB connection and adjusting the setting as shown in
USB connectors 36 (
In particular,
Thus, circuit interrupter system 2′ utilizing USB module 78 is able to provide all of the functionality described herein in connection with circuit interrupter system 2 for a circuit interrupter 4′ having a standard test port 80.
In another embodiment, GUI 42 may be used implement diagnostic/wellness functionality when computing device 10 is coupled to electronic trip unit 8 or electronic trip unit 8′ using the USB connection. In particular, GUI 42 may be configured to monitor the “health” of either the system to which circuit interrupter 4 or circuit interrupter 4′ is connected or a component of the circuit interrupter 4 or circuit interrupter 4′ itself. For example, in a wind turbine, if the main gear wears, an abnormal pattern will be present in the current of the wind turbine. Thus, if circuit interrupter 4 or circuit interrupter 4′ is connected to such a wind turbine, GUI 42 may measure and monitor the current of the wind turbine (the relevant data is communicated from the microprocessor of the electronic trip unit to microprocessor 38 of computing device 10 through the USB interconnection between the two devices) and then compare that monitored current to a normal, expected current pattern. When abnormalities in the monitored current pattern are detected (as compared to a normal, expected pattern), wear of the main gear may be indicated. As will be appreciated, this concept (diagnostics based on current patterns) is not limited to just wind turbines, but may be applied in other areas as well wherein abnormal current patterns may indicate an adverse or deteriorated health state of a component. As other examples, GUI 42 may be configured to monitor current transformer (CT) insulation breakdown and/or contact wear/breakdown (based on measured resistances) within circuit interrupter 4 or circuit interrupter 4′, with such conditions being displayed on GUI 42. It will be appreciated that the above embodiments are merely exemplary and that still other diagnostic/wellness functionalities may be implemented within GUI 42.
In each of the embodiments described herein, the trip unit microprocessor (μP) 16 has a serial interface to a separate USB processor. In an alternative embodiment, trip unit microprocessor (μP) 16 may have USB functionality built therein, so as to eliminate the need for the serial interface to a separate USB processor. While specific embodiments of the disclosed concept have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the disclosed concept which is to be given the full breadth of the claims appended and any and all equivalents thereof.
