DESC:FIELD OF THE INVENTION
The present invention relates to switchgears and specifically concerning about molded case circuit breakers (MCCB). Particularly, the invention relates to MCCB using microprocessor based release with auxiliary accessory mounting. More particularly the invention relates to a system, and a method for life count of circuit breakers.

BACKGROUND OF THE INVENTION AND PRIOR ART

Generally it is known to couple one of the release units to a MCCB for providing overload and short circuit protections such as
· Thermal- magnetic release
· Microprocessor based release
Those releases are mechanically coupled together with the MCCB basic unit and are provided by actuating means for actuating the operation of the electrical device (for example opening or closing of a circuit or similar).
It is known that the trip life of mechanism involves de-latching of the mechanism which is sensed by the trip alarm contact of the MCCB. It is also known that each trip cycle results in reduction of the life of the circuit breaker. In the known art, mechanical life and electrical life counting of the breaker becomes essential for the preventive maintenance of the breaker. Though it was known that trip cycle reduces the life of a circuit breaker, it was not known how one could monitor or count life of a circuit breaker.
Thus there the present inventors realized that there is a need for a system for counting trip life, mechanical life and Electrical life of the breakers in conjunction with the release and accessory modules. Circuit breakers form one of the most important parts of a power transmission and distribution system which involves quite good number equipments which are sometimes very costly. During any fault conditions it is required to break or isolate equipment or equipments from a particular circuit and then circuit breakers play a major role by tripping at an instantaneous faulty condition which would otherwise turn to be unhealthy for the transmission and distribution power system.
With this concept one can utilize effectively the already existing modules for preventive maintenance purposes.

OBJECTS OF THE INVENTION

A basic object of the present invention is to overcome the disadvantages / drawbacks of the prior art.
Another object of the present invention is to provide a system for life count of circuit breakers.
Another object of the present invention is to provide a method for life count of circuit breakers.
These and other advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.
In an aspect of the present invention, there is provided a system for life count of a circuit breaker, said system comprising:
a release unit for sensing and processing a trip signal;
a trip alarm contact and an auxiliary contact for providing a trip alarm contact signal and an auxiliary signal; and
a flux shift device (FSD) and a shunt trip unit for tripping said circuit breaker; and
a life counter unit operationally connected with the release unit, the trip alarm contact, the auxiliary contact, the FSD, and the shunt trip unit,
wherein the life counter unit computes the life remaining count of said circuit breaker by sensing signals from said FSD, shunt trip unit, auxiliary contact and trip alarm contact.

In another object of the present invention, there is provided a method for life remaining count of a circuit breaker; said method comprising steps of:
feeding a trip signal from trip alarm contact and an auxiliary contact in a release unit,
processing and sensing from said trip alarm contact and said auxiliary signal(s),
selectively relaying said trip signal(s) to a flux shift device and a shunt trip unit for tripping the circuit breaker,
computing the life remaining count of the circuit breaker by sensing the trip signal from said FSD, said shunt trip unit, said auxiliary contact and said trip alarm contact using a life counter unit.
Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

The following drawings are illustrative of particular examples for enabling methods of the present invention, are descriptive of some of the methods, and are not intended to limit the scope of the invention. The drawings are not to scale (unless so stated) and are intended for use in conjunction with the explanations in the following detailed description.

Figure 1 illustrates the various ways in which this logic could be made a part of the moulded case circuit breaker as a system.

Figure 2 illustrates block diagram of the invention.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure.

Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE INVENTION
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.
By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
Accordingly, present invention provides a system, and a method for life count of circuit breakers.
This feature shall be built as a part of the micro-processor based release with indispensable or factory mounted shunt, Trip alarm contact and Microprocessor based release.
The release feature is as follows: the Trip Alarm contact feedback and Auxiliary contact feedback are fed to the micro processor based release for processing. The release senses various faults and selectively relays over current faults to FSD and other faults to the Shunt Trip unit. In the case of failure in operation of FSD, the Shunt release is relayed with the “Trip” signal hence improving the otherwise complete dependency on the Flux Shift Device.
The features described above can be built into a separate module (externally/Internally) and can act as an extended feature for the already available microprocessor based systems operating independent of feedbacks from other accessories like Auxiliary and Trip Alarm contacts.
This release feature if modular is to be mounted on the UV accessory mounting cavity. It is to be connected through buses with the Micro processor based Release and the Auxiliary and Trip Alarm ad-on modules.
The trip life is computed by electronically counting the contact change feedback from Trip Alarm contact. The mechanical life is computed by electronically counting the contact change feedback from Auxiliary contact. The mechanical life is computed by electronically counting the contact change feedback from Auxiliary contact ‘AND’ing with Rogowski signal presence in specified limits as per requirements.
Trip Life :: Mechanical trip life :: Count of Trip Alarm of Contact
Electrical Life of breaker contacts:: Auxiliary count (AND) Continuity sensed through release Rogowski
Mechanical Life of breaker:: Trip Life of the breaker (AND) Electronic FSD Life
In the case when a shunt is used to improve the Life of the breaker and excluding dependency of FSD for tripping the breaker Mechanical life of breaker will be independent in the FSD Life. Remaining life of the breaker is to be computed by subtracting the above values from the predefined constant values.
Fig1 represents the various ways in which this logic could be made a part of the moulded case circuit breaker as a system. This feature in-built in the Release unit can display the details on the release itself or communicate the present status to a remote location as well.
Figure 2 shows the implementation block diagram. The Microcontroller unit of the device senses the FSD signal, Auxiliary signal, Trip Alarm contact signal and sense signal to compute the Life Remaining count of the circuit breaker. In the block diagram, Rogowski signals are preceded by signal conditioning circuits before feeding into the microcontroller. The counting happens by a soft logic built into the micro controller. ,CLAIMS:1. A system for life count of a circuit breaker, said system comprising:
a release unit for sensing and processing a trip signal;
a trip alarm contact and an auxiliary contact for providing a trip alarm contact signal and an auxiliary signal; and
a flux shift device (FSD) and a shunt trip unit for tripping said circuit breaker; and
a life counter unit operationally connected with the release unit, the trip alarm contact, the auxiliary contact, the FSD, and the shunt trip unit,
wherein the life counter unit computes the life remaining count of said circuit breaker by sensing signals from said FSD, shunt trip unit, auxiliary contact and trip alarm contact.
2. The system as claimed in claim 1, wherein trip life of said circuit breaker is determined by counting the contact change signal from said trip alarm contact.
3. The system as claimed in claim 1, wherein mechanical life of said circuit breaker is determined by counting the contact change signal from said auxiliary contact.
4. The system as claimed in claim 1, wherein electrical life of said circuit breaker is determined by subtracting the contact change signal from said auxiliary contact form a signal from Rogowski.
5. The system as claimed in claim 4, wherein said Rogowski signal is present in specified limits as per requirements.
6. The system as claimed in claim 1, wherein said life counter unit is a microcontroller.
7. The system as claimed in claim 1, wherein said release unit is a microprocessor based release unit.
8. The system as claimed in claim 1, wherein said life counter unit can be attached externally/internally to said release unit.
9. A method for counting remaining life of a circuit breaker; said method comprising steps of:
feeding a trip signal from a trip alarm contact and an auxiliary contact in a release unit;
processing and sensing from said trip alarm contact and said auxiliary signal(s);
selectively relaying said trip signal(s) to a flux shift device and a shunt trip unit for tripping the circuit breaker; and
computing the life remaining count of the circuit breaker by sensing the trip signal from said FSD, said shunt trip unit, said auxiliary contact and said trip alarm contact using a life counter unit.