DESC:TECHNICAL FIELD
[0001] The present disclosure relates generally to circuit breakers, and more particularly to determination of re-rating of circuit breakers under different ambient conditions, environment factors, and enclosure sizes.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] In electronics, de-rating (or de-rating) is the operation of a device at less than its rated maximum capability in order to prolong its life. Typical examples include operation below the maximum power rating, current rating, or voltage rating.
[0004] Circuit breakers may be used in industrial, commercial, and residential applications for protecting electrical devices from over-current situations. Circuit breakers, trip units, and/or electronic trip units with circuit breakers may measure electrical current of a load using a secondary current. The secondary current may be derived from the electrical current of the load through current transformers (CT) and/or Rogowski sensors. CTs and Rogowski sensors provide reduced current proportional to the electrical current of the load. The reduced current (noted secondary current above) may be used by the circuit breaker to perform protection analysis, metering, and other functionality included in the circuit breaker.
[0005] Circuit breakers may be used as a replacement for conventional fuses, although some circuit breakers function slower than fuses, and may include complicated mechanical components. However, fusing provides only a single level of protection. That is, fuses are generally non-adjustable. However, circuit breakers may be rated for many applications, and may be re-rated to increase breaker selectivity. For example, a circuit breaker rated to switch up to 100 amps may be adjusted to trip at 30 amps. However, this may require physically swapping rating plugs and setting internal gains for detection devices within the circuit breaker for the new trip setting. It is appreciated that this requires an operator to identify and adjust the re-rating current level as necessary for each application, save these setting in the circuit breaker (or trip unit), and test to ensure proper and accurate current level tripping.
[0006] While in operation, a circuit breaker can heat up due to heat generation, wherein temperature of the breaker may rise to more than 100 ?C, which can damage the breaker and also affect the efficiency thereof. A current rating is typically provided to the circuit breaker to keep temperature of breaker within safe limits. As circuit breaker operates under different ambient conditions for example in open condition, inside the enclosure with different IP ratings, and mounting location inside the enclosure, de-rating of the breaker may be required if the breaker is operating in hotter micro-ambient condition(s).
[0007] There is therefore a need in the art for efficient and quick determination of re-rating for a given circuit breaker based on its operating and environmental conditions.
[0008] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0009] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0010] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0011] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0012] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

OBJECTS OF THE INVENTION
[0013] It is an object of the present invention to provide a system and method for efficient and quick determination of re-rating for a given circuit breaker.
[0014] It is an object of the present invention to provide a system and method for determination of re-rating of a given circuit breaker based on its operating and environmental conditions.
[0015] It is an object of the present invention to provide a circuit breaker for which voltage or current rating can be dynamically adjusted.
[0016] It is an object of the present disclosure to provide a circuit breaker that can be configured to work based on adjusted re-rating determined based on operating and environmental condition.

SUMMARY
[0017] The present disclosure relates generally to circuit breakers, and more particularly to determination of re-rating of circuit breakers under different ambient conditions, environment factors, and enclosure sizes.
[0018] In an aspect, the present disclosure enables computation of switchgear rating under various ambient conditions, wherein the proposed system can require any or a combination of enclosure dimensions, enclosure Ingress Protection (IP) rating (outlet opening area), watt loss due to other breakers inside the enclosure, cable and bus-bar dimensions, and mounting locations of the circuit breaker to be rated, among other configured/desired parameters (collectively referred to rerating computation attributes). In an aspect, the proposed system, based on the above-mentioned rerating computation attributes can measure working parameters comprising any or combination of current flowing through the circuit breaker, micro-ambient temperature, and temperature at critical locations/points of the breaker, and based on the same, can associate the re-rated current with the respective circuit breaker.
[0019] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components

BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0021] FIG. 1 illustrates an exemplary block diagram showing various components required to compute are-rating for a circuit breaker in accordance with an embodiment of the present disclosure.
[0022] FIG. 2 illustrates an exemplary flow diagram showing various steps required to compute a re-rating for a circuit breaker in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0023] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0024] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0025] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0026] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0027] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0028] The present disclosure relates generally to circuit breakers, and more particularly to determination of re-rating of circuit breakers under different ambient conditions, environment factors, and enclosure sizes.
[0029] In an aspect, the present disclosure enables computation of switchgear rating under various ambient conditions, wherein the proposed system can require any or a combination of enclosure dimensions, enclosure IP rating (outlet opening area), watt loss due to other breakers inside the enclosure, cable and bus-bar dimensions, and mounting locations of the circuit breaker to rated, among other configured/desired parameters (collectively referred to rerating computation attributes). In an aspect, the proposed system, based on the above-mentioned rerating computation attributes, can measure current flowing through the circuit breaker, micro-ambient temperature, and temperature at critical locations of the breaker, and based on the same, can associate the re-rated current with the respective circuit breaker.
[0030] FIG. 1 illustrates an exemplary block diagram of a system to computer e-rating of a circuit breaker and to configure the circuit breaker accordingly in accordance with an embodiment of the present disclosure. Circuit breaker is a device that is meant for making, breaking, and carrying continuous current under versatile loads that are mainly slightly resistive or highly inductive loads. While the circuit breaker carry continuous current or rated load current, due to resistive or other form of losses, heat is generated that may be responsible for increase in temperature of the current carrying path of the circuit breaker. In most of the cases, the circuit breaker is designed to maintain the temperature of the current carrying path within their specified limit as mentioned in the respective product standard IEC 60947-2 and IEC 60947-1. However, in some cases it is often observed that due to lower enclosure size and adverse environment and ambient condition, the overall temperature rise of the terminal even with silver plated contacts can reach beyond a limit specified in above standards. In order to comply with the product standard specification, the current rating needs to be adjusted (Re-rated) and the circuit breaker needs to be configured accordingly.
[0031] The system 100 can compute/determine re-rating of a circuit breaker 126 for different ambient conditions. The system 100 can include an user interface 102 configured to receive input parameters that include, but are not limited to, dimensions of an enclosure 104 under which the circuit breaker 126 has to work, IP rating (outlet opening area) of the enclosure 106, watt loss due to other breakers inside the enclosure 108, dimensions of cable110, dimensions of bus-bar 112, and mounting locations 114 of the circuit breaker 126.The system 100 can include a user interface 102 that can be used for manual data entry for various options. The system 100 can be configured to receive working parameters that include, but are not limited, to current flowing through the circuit breaker 126, micro-ambient temperature, and temperature at critical locations/points of the circuit breaker. The system 100 includes a working parameter receive module 116 configured to receive working parameters that includes but are not limited to any or combination of initial rated current (Ir), temperature rise (TR) of the circuit breaker, and ambient temperature (Tamb) for the circuit breaker and a re-rating determination module 122 configured to determine re-rating current for the circuit breaker based on the input parameters and the working parameters.
[0032] In an exemplary implementation, the system 100 can include a current sensor 118 to sense current flowing through the circuit breaker, attached with the circuit breaker. In an exemplary implementation, the micro-ambient temperature near the circuit breaker 126can be received from a temperature sensors120configured with the system. Similarly the temperature at critical points of the circuit breaker can be received from appropriate temperature sensors 120.In an exemplary implementation, the system can determine/compute re-rated current for the circuit breaker based on the received input parameters and the received working parameters. In an implementation, the working parameters can be fed manually by a user.
[0033] In an aspect, the system 100 can be configured as a combination of hardware and software integration. In an aspect, the system 100 can have a current source for constant current supply, amounting arrangement (enclosure) for circuit breaker 126, a temperature measurement panel (also referred interchangeably as temperature sensor 120), a current sensor 118 or amV drop measurement panel, and a user interface 102 to enter any or a combination of dimensions of an enclosure 104 under which the circuit breaker has work, IP rating (outlet opening area) of the enclosure 106, watt loss due to other breakers inside the enclosure 108, dimensions of cable 110, dimensions of bus-bar 112, and mounting locations 114 of the breaker etc. that can be used as input parameters for determining a new rated (referred interchangeably as re-rated) value for the circuit breaker. In an aspect, the system 100 can further include a display 124that can display various input and re-rated value (safe current or re-rated current) as determined.
[0034] In an exemplary implementation, system 100 can receive working parameters comprising of any or combination of initial rated current (Ir), temperature rise (TR) sensed in the circuit breaker, and ambient temperature (Tamb) for the circuit breaker sensed during operation. In an exemplary implementation, such input parameters and working parameters can be received from a user/operator.
[0035] In an exemplary implementation, the micro-ambient temperature (Tmicro) inside the enclosure can be calculated based on addition of all the wattage loss inside the enclosure sensed by the mV drop measurement panel. The system 100 can computer an absolute temperature (Tabs) for the circuit breaker that can be sum of the micro-ambient temperature (Tmicro). The system can compute wattage loss required to achieve the temperature rise (TR) within safe limits (W) based on which new rating (In) can be calculated for the circuit breaker placed inside the enclosure. That is, the current value can be computed based on the watt loss. The system can check if the computed new rating In (also referred interchangeably as re-rated value or re-rated current) <= Ir (initial rating current value), and on affirmative determination, the system concludes the new rating (In) as re-rated current. If, the new rating (In) is not less and or equal to Ir, the Irremains as rated current.
[0036] In an aspect, system 100, as shown in FIG. 1, can be configured to determine re-rated/new rating of circuit breaker to work within a fixed enclosure size, ambient temperature, and environmental and mounting conditions, among other configurable parameters that can impact the operation/configuration/conditions of the circuit breaker.
[0037] In an aspect, under normal operating conditions, switchgear can be mounted in a panel with other switchgears inside an enclosure. Because of confined environment gas inside, the enclosure heats up. Taking this into account, a re-rating of switchgear is required to ensure safe operation, for which, the system 100 can be used to provide new rating for a wide range possible enclosures and mounting conditions.
[0038] As shown in FIG. 1, multiple parameters can be received from an external source or can be computed by the proposed system in real-time based on which re-rating current can be computed/determined for a given circuit breaker. For instance, the parameters can include, but are not limited to, size of the enclosure in which the circuit breaker is configured, IP rating of the operating area where the circuit breaker is configured, type of installation, circuit breaker mounting location, cable size, bus bar size, wattage loss due to other circuit breakers, and current flowing through the circuit breaker. Other parameters that can be computed by the system can include voltage (mV) drop, terminal temperature of the circuit breaker, ambient temperature of the circuit breaker, based on which the re-rating of the current for the circuit breaker can be done.
[0039] For example, the system can sense/measure working parameters, for example temperature rise-65 oC, Current (Ir) = 3200 and ambient temperature = 35 oC, and receive user inputs, for example enclosure dimensions= 800*8000*600, IP rating: IP43, watt loss due to other breaker=0W, cable and bus size: 3*1000*10 etc. On receiving the measured working parameters and user inputs, the system can calculate watt loss (i.e. 1867 W) for 3200 A current input, micro-ambient temperature, for example 62 oC, and calculate new current rating for the micro-ambient temperature of 62 oC. The system can dynamically keep calculating the new current ranting until a solution converges. For given example, the system can recommend and/or set the rerated current as 2184 A.
[0040] FIG. 2 illustrates an exemplary flow diagram 200 showing various steps required to compute a re-rating for a circuit breaker in accordance with an embodiment of the present disclosure. As can be seen, at step 202, the proposed method can measure working parameters comprising of any or combination of initial rated current (Ir), temperature rise (TR) of the circuit breaker, and ambient temperature (Tamb) for the circuit breaker, and at step 204, can receive, any or a combination of size/dimensions of the enclosure in which the circuit breaker is configured, IP rating of the operating area where the circuit breaker is configured, type of installation, circuit breaker mounting location, cable size, bus bar size, and wattage loss due to other circuit breakers, among other parameters. Such input parameters and working parameters can be received from a user/operator. In an exemplary implementation, the temperature rise (TR) can be calculated based on input of temperature sensors installed with the circuit breaker, and the ambient temperature can be calculated by adding micro-ambient temperature of the circuit breaker at different points, wherein the micro-ambient temperature is determined based wattage loss observed at the different points.
[0041] At step 206, micro-ambient temperature (Tmicro) inside the enclosure can be calculated based on addition of all the wattage loss sensed inside the enclosure, and at step 208, absolute temperature (Tabs) for the breaker can be calculated as sum of the micro-ambient temperature (Tmicro). In an exemplary implementation, a temperature sensor can be placed with the circuit breaker to monitor temperature ambient temperature at different points. At step 210, wattage loss (W) required to achieve TR within safe limits can be computed, based on which, at step 212, new TR rating is calculated inside the enclosure (In). That is, the current value is computed based on the watt loss.
[0042] At step 214, it is determined if In (current value) = Ir (initial current value), which if YES, enables, at step 216, the method ends by marking of the new re-rating the current for the circuit breaker to be “In”, else if NO, Ir is set as In at step 218 and the method flows back to step 206.
[0043] In an aspect therefore, prior arts in this domain adjust power supply under dynamic ambient condition to de-rate devices, whereas the present disclosure predicts current rating of devices under various ambient temperatures, venting and enclosure types, among other environmental/operational parameters as discussed above.
[0044] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[0045] The present invention provides a system and method for efficient and quick determination of re-rating for a given circuit breaker.
[0046] The present invention provides a system and method for determination of re-rating of a given circuit breaker based on its operating and environmental conditions.
[0047] The present invention provides a possibility for dynamic adjustment of current rating at which circuit breaker can operate.
[0048] The present invention provides a circuit breaker that can be configured to work based on adjusted re-rating determined based on operating and environmental condition.
,CLAIMS:1. A method for re-rating a circuit breaker, the method comprising-
collecting input parameters comprising any or combination of dimensions of an enclosure , ingress protection ( IP ) rating of the enclosure, watt loss due to other breakers inside the enclosure, dimensions of cable, dimensions of bus-bar and mounting locations of a circuit breaker to be re-rated;
receiving working parameters comprising any or combination of initial rated current (Ir), temperature rise (TR) of the circuit breaker, and ambient temperature (Tamb) for the circuit breaker; and
determining re-rated current for the circuit breaker based on the input parameters and the working parameters.

2. The method of claim 1, wherein the method further comprises step of associating the re-rated current with the circuit breaker.

3. The method of claim 1, wherein the working parameters are provided manually by a user.

4. The method of claim 1,wherein the temperature rise (TR) is calculated based on input of temperature sensors installed with the circuit breaker.

5. The method of claim of claim 1, wherein the ambient temperature is calculated by adding micro-ambient temperature of the circuit breaker at different points inside the enclosure, wherein the micro-ambient temperature is determined based wattage loss observed at the different points.

6. The system for re-rating a circuit breaker, the system comprising-
an user interface configured to receive input parameters comprising any or combination of dimensions of an enclosure , ingress protection ( IP ) rating of the enclosure, watt loss due to other breakers inside the enclosure, dimensions of cable, dimensions of bus-bar and mounting locations of a circuit breaker to be re-rated;
a working parameter receiving module configured to receive working parameters comprising any or combination of initial rated current (Ir), temperature rise (TR) of the circuit breaker, and ambient temperature (Tamb) for the circuit breaker; and
re-rating determination module configured to determine re-rating current for the circuit breaker based on the input parameters and the working parameters.

7. The system of claim 5, wherein the system is configured to associate the re-rated current with the circuit breaker.

8. The system of claim 5, wherein the working parameters are provided manually by a user.

9. The system of claim 5, wherein the temperature rise (TR) is calculated based on input of temperature sensors installed with the circuit breaker.

10. The system of claim 5, wherein the ambient temperature is calculated by adding micro-ambient temperature of the circuit breaker at different points inside the enclosure, wherein the micro-ambient temperature is determined based wattage loss observed at the different points.