FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Apparatus and Method to Display Fault History in a Circuit Breaker Using
Hybrid Display"
2. APPLICANT:
(a) NAME: Larsen & Toubro Limited
(b) NATIONALITY: Indian Company registered under the
provisions of the Companies Act-1956.
(c) ADDRESS: LARSEN & TOUBRO LIMITED,
L&T House, Ballard Estate, P. 0. Box: 278, Mumbai 400 001, India
3. PREAMBLE TO THE DESCRIPTION:
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Apparatus and Method to Display Fault History in a Circuit Breaker Using
Hybrid Display
FIELD OF INVENTION
The present invention relates to the field of display systems. More particularly, the present invention relates to an information display system for displaying information pertaining to circuit breaker tripping.
BACKGROUND OF THE INVENTION
Generally, electrical faults such as short circuiting, overloading and earth faults in a power distribution network of a power distribution system may cause irreparable damage to the power distribution system. Further, such electrical faults may also cause fire hazards. A circuit breaker is an automatically operated electrical switch that cuts off electrical flow to the remaining power distribution network or isolates the faulty power distribution network in an event of a possible electrical fault, such as short-circuit, overload, and earth faults, thereby protecting the power distribution system against damages caused by short-circuiting or overloading. The circuit breaker is generally an electro-magnetic device that localizes the electrical fault by isolating the faulty power distribution network, thereby preventing damage to the entire power distribution system. More specifically, a trip unit detects a fault conditions based on current and voltage measurements and issues a trip command to the circuit breaker. The circuit breaker in-turn, by interrupting the electrical continuity immediately discontinues electrical flow to the remaining power distribution network, thereby isolating the faulty power distribution network and protecting the remaining power distribution network against any further damage. The trip unit is an intelligent device that measures system parameters such as voltage, current, power etc., and based on the measurements performed, controls the operation of the circuit breaker. The trip unit operates in conjunction with the circuit breaker to protect the power distribution system against the electrical faults

such as overload, short circuit, earth fault, etc. by isolating the faulty power distribution network.
As the circuit breaker trips in case of an electrical fault, the power supply to the remaining power distribution network as well as the trip unit is disrupted. The circuit breaker is generally powered through a current transformer. Further, as the circuit breaker trips, there is no flow of electrical current to the circuit breaker and no power is available for operating the conventional display systems used with the circuit breaker. Accordingly, the conventional display systems fail to provide any information pertaining to circuit breaker tripping and in most of the cases, the reason for the tripping of the circuit breaker, i.e. if the tripping of the circuit breaker has occurred due to short circuiting, overload or earth faults is either not recorded, or is recorded but not displayed by the conventional circuit breakers and trip units, as a result the exact nature of the electrical fault that caused the tripping of the circuit breaker is not known to the maintenance personal. However, such information may be required for the timely rectification of the electrical fault. Further, the maintenance personnel is required to analyse the various tripping parameters such as current, voltage and power at the time of the electrical fault, wherein analysis of such tripping parameters assists the maintenance personnel in identifying the electrical fault and timely rectifying the electrical fault. Further, various other information such as day, date and time at which the circuit breaker tripped may be useful data required for ensuring proper maintenance and safety of the power distribution system. However, all such information is not recorded and displayed in most of the conventional trip units and circuit breakers. Further, some other conventional display systems for displaying the various tripping parameters and other information pertaining to tripping require dedicated display devices powered by an independent power source such as a battery for continuously displaying the tripping parameters and other information related to tripping, as after the tripping of the circuit breaker, the current transformer that was initially supplying electrical current to the circuit breaker before tripping, no longer supplies electrical current to the circuit breaker and the convention display systems require electrical power for operating. In case of such display systems, the information is

displayed on different screens, for example, the user has to navigate through different screens for accessing the different information and such display systems are difficult to operate. Display systems having such configuration, may require the user to collect the information from different display screens and may cause confusion and undue delay. Further, the conventional display systems are not properly controlled and are inaccurate and ineffective.
Accordingly, there is a need for a display system that not only displays system parameters when there is no tripping but also displays all the information pertaining to the circuit breaker tripping such as the nature of the electrical fault that caused tripping, the date and time at which the circuit breaker tripped and the tripping parameters such as current and voltage on one screen. Further, there is a need for a display system that redundantly displays information irrespective of circuit breaker tripping. Furthermore, there is a need for a display system that continuously displays information pertaining to circuit breaker tripping without requiring continuous supply of electrical power. Still further, there is a need for a display system that assists the maintenance personnel to timely rectify the electrical fault by providing necessary information to the maintenance personnel in an easy to understand and readable format at one place. Further, there is a need for a display system that enables the maintenance personnel to read the information displayed thereon from a wider viewing angle. Furthermore, there is a need for a display system that is reliable, easy to use and economical. Still further, there is a need for a display system that is sturdy, does not fail frequently and has longer service life. Further, there is a need for a display system that may be easily retrofitted and used with any of the conventionally known circuit breakers and trip units.
OBJECTS OF THE INVENTION
Some of the objects of the present invention are described herein below:

It is an object of the present invention to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present invention is to provide a display system that displays all the information pertaining to circuit breaker tripping such as the nature of the electrical fault that caused tripping, the date and time at which the circuit breaker tripped and the tripping parameters such as current and voltage.
Another object of the present invention is to provide a display system that displays all information regarding circuit breaker tripping on one screen, thereby eliminating the need to navigate to different screens for accessing different set of information.
Yet another object of the present invention is to provide a display system that continuously displays information pertaining to circuit breaker tripping without requiring continuous supply of electrical power and is operational even after tripping.
Still another object of the present invention is to provide a display system that eliminates the need for a dedicated power source for continuously displaying information pertaining to circuit breaker tripping.
Yet another object of the present invention is to provide a display system that assists the maintenance personnel to timely rectify the electrical fault by providing necessary information to the maintenance personnel in a easy to understand and readable format.
Still another object of the present invention is to provide a display system that enables the maintenance personnel to read the information displayed thereon from a wider viewing angle.
Yet another object of the present invention is to provide a display system that is reliable.

Another object of the present invention is to provide a display system that is easy to use.
Still another object of the present invention is to provide a display system that is economical.
Another object of the present invention is to provide a display system that is sturdy, does not fail frequently and has longer service life.
Still another object of the present invention is to provide a display system that may be easily retrofitted and used with any of the conventionally known circuit breakers and trip units.
Yet another object of the present invention is to provide a display system that displays useful data required for ensuring proper maintenance and safety of the power distribution system.
SUMMARY OF THE INVENTION
A display system for redundantly displaying information is disclosed in accordance with an embodiment of the present disclosure. The display system includes a controller, an output console and an E-paper display device. The controller is functionally coupled to a trip unit and a circuit breaker, wherein the trip unit measures system parameters corresponding to current received from current transformer and performs calculations to determine threshold values of the system parameters. The controller detects a fault condition based on the measurements and calculations performed by the trip unit and issue a trip command to the circuit breaker. The controller further issues a display actuation command corresponding to measurements performed by the trip unit before issuing the trip command. The output console includes at least one display device and is functionally coupled to the controller. The at least one display device derives electrical power from the

current transformer and displays system parameters measured by the trip unit in case no fault condition is detected and no tripping occurs. The E-paper display device is functionally coupled to the controller and initially derives electrical power from the current transformer to electronically "print" and display information pertaining to circuit breaker tipping upon receiving the display actuation command from the controller. The E-paper display device continuously displays the information pertaining to circuit breaker tipping even after the electrical power from the current transformer is disrupted due to the circuit breaker getting tripped, thereby facilitating redundant display of desired information at all times.
Typically, the controller is a Programmable Logic based Controller (PLC).
Generally, the at least one display device is a Liquid Crystal Display (LCD).
Alternatively, the display device is an (Organic Light Emitting Diodes) OLED based display device.
In accordance with another embodiment, the display device is a Thin Film Transistor (TFT) based display screen.
Preferably, the E-dispiay device is mounted along with other display devices on a single unit.
Typically, the E-paper display device gets refreshed by an electrical signal issued by the controller upon restoring of the electrical power supply to the controller after rectification of the electrical fault.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates a schematic block diagram depicting interaction of various auxiliary elements with a controller of a display system in accordance with an

embodiment of the present disclosure, wherein the controller regulates the operation of a circuit breaker, an E-paper display device and an output console;
Figure 2a - Figure 2c illustrates examples of different contents displayed on the E-paper display for providing information pertaining to circuit breaker tripping under different circumstances;
Figure 3 illustrates flow diagram depicting the various steps followed by the display system for displaying information pertaining to circuit breaker tripping; and
Figure 4 illustrates an E-paper display device disposed along with at least one display devices of an output console for displaying information pertaining to circuit breaker tripping in accordance with an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
The invention will now be described with reference to the accompanying drawings which do not limit the scope and ambit of the invention. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific

embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
The .terms Electronic paper or e-paper used in the specification refers to an electronically "printed" screen that enables viewing of contents thereon using reflected light, unlike using backlight as is in case of Liquid Crystal Display (LCD) screens, thereby continuously displaying the contents electronically "printed" thereon without requiring continuous supply of electrical power, further, the contents electronically "printed" and displayed on the Electronic paper or e-paper can be "erased" and "rewritten" as often as desired.
A circuit breaker is an automatically operated electrical switch that cuts off electrical flow to the remaining power distribution network or isolates the faulty power distribution network in an event of a possible electrical fault, such as short-circuit, overload, and earth faults, thereby protecting the power distribution system against damages caused by short-circuiting or overloading. The circuit breaker is generally powered through a current transformer. However, as the circuit breaker trips, there is no flow of electrical current to the circuit breaker and no power is available for operating the conventional display systems used with the circuit breaker, accordingly, the conventional display systems fail to display the cause for the circuit breaker trip. Under such circumstances it becomes difficult for the maintenance personnel to rectify/debug the faulty system without knowing the exact cause of the fault.
The present disclosure envisages a display system for redundantly displaying information such as system parameters, irrespective of the tripping of a circuit-

breaker used in a power distribution system. More specifically, the display system displays information such as system parameters measured by a trip unit in case no fault condition is detected and no tripping occurs and information pertaining to circuit breaker tripping such as the nature of the electrical fault that caused tripping, the date and time at which the circuit breaker tripped and the tripping parameters such as current and voltage even after the electrical power from a current transformer is disrupted due to the circuit breaker getting tripped. Further, the display system displays all information regarding circuit breaker tripping on one screen, thereby eliminating the need to navigate to different screens for accessing different information. Such a display system facilitates constant monitoring of an electrical distribution system of which the circuit breaker is a part of.
The display system of the present invention achieves the desired redundancy by duplication of critical display devices, more particularly, by using an E-paper display device along with other display devices such as Liquid Crystal Display (LCD) and (Organic Light Emitting Diodes) OLED based display device with the intention of increasing reliability of the system. The E-paper display device initially derives power from the current transformer to electronically "print" and display information pertaining to circuit breaker tipping such as the nature of the electrical fault that caused tripping, the date and time at which the circuit breaker tripped and the tripping parameters such as current and voltage. Thereafter, the E-paper display device continuously displays the information pertaining to circuit breaker tipping even after the electrical power supply from the current transformer is disrupted due to the circuit breaker getting tripped, thereby facilitating redundant display of desired information at all times. However, the E-paper display device of the display system of the present invention is not limited to display only the above mentioned information and can be used for displaying other additional information.
The E-Paper display displays all information on one screen, thereby eliminating the discomfort of navigating through different screens for accessing the information. The E-Paper display displays all information regarding circuit breaker tripping in case the circuit breaker is tripped due to an electrical fault. The E-Paper display

retains the contents displayed thereon until the E-paper display is refreshed. The E-paper display device can be refreshed by an electrical signal upon restoration of the electrical power supply that occurs after rectification of the electrical fault. In the nut shell, the E-Paper display is used only when the circuit breaker is tripped, and in all other conditions an LCD/OLED/TFT screen is used for display.
Referring to Figure 1, a schematic block diagram depicting interaction of various auxiliary elements with a controller (101) of a display system (100) is disclosed. As illustrated in Figure 1, the controller (101) directly or indirectly interacts with different auxiliary elements that includes a current transformer (110), a flux shift device (111), a Rogowski/CT (neutral) (112), a Rogowski coil (113), a test kit programming connector (114), a Liquid Crystal Display (LCD) (115), an E- paper display (116), a LED indication display (117), a dip switch (118), a dip switch selection (119), a FSD trip circuitry (120), a power supply (] 21), a thermal memory circuitry (122) and a signal conditioning circuit (123).
The controller (101) is a microcontroller based controller. In accordance with another embodiment, the controller is a Programmable Logic Controller (PLC) based controller. The controller (101) mainly interacts with a trip unit that includes the FSD trip circuitry (120) and regulates the operation of a circuit breaker via a dip switch (118), an E-paper display device (116) and an output console, wherein the LED indication based display (117) and the LCD display (115) are part of the output console. In accordance with an embodiment, the E-paper display device (116), the LED indication based display (117) and the LCD display (115) are all configured CP. a single unit.
As illustrated in Figure 1, the controller (101) is functionally coupled to the FSD trip circuitry (120) of the trip unit and the dip switch (118) of the circuit breaker. The trip unit also referred to as the Electronic Trip Unit (ETU) senses the current from the current transformer (110) and power supply (121), operates in conjunction with the controller (101) to do computation for fault currents, and finally sends electrical signals to the circuit breaker based on sensed current values and fault

current values, for causing tripping of the circuit breaker. More specifically, the trip unit measures system parameters corresponding to current received from the current transformer (110) and perform calculations for threshold values of the system parameters. The trip unit typically uses an air core signal sensor for measuring system parameters. However, the present invention is not limited to any particular type and configuration of the sensor used by the trip unit for measuring system parameters. The signal condition circuit (123) conditions the sensor signals and passes it on to the controller (101). The controller (101) detects a fault condition based on the measurements and calculations performed by the trip unit and issue a trip command to the circuit breaker. More specifically, the controller (101) digitizes the analog signal and checks whether the input current has exceeded the set threshold. If the current exceeds the set threshold for set duration of time, the controller sends electrical pulses to an electromechanical relay and thus trips the breaker, thereby, isolating the faulty system from rest of the power distribution network. The controller (101) further issues a display actuation command before issuing the trip command. More specifically, the display actuation command actuates the display of the E-Paper display device (116) corresponding to measurements performed by the trip unit before issuing the trip command. The E-paper display device (116) is activated, few milliseconds before the circuit breaker could trip. Gnce the E-Paper device (116) is activated, the electrical parameters leading to the fault and the cause of fault are displayed on to the E-Paper display device (116) and then the circuit breaker issues a trip command. As the circuit breaker trips, the power supply to the circuit breaker is disrupted, however, the E-paper display device (116) continues to display the cause of the trip along with the electrical parameters as illustrated in Figure 2a and Figure 2c. Thus even in the absence of electrical power, the end user/ maintenance personnel will know the reason for trip, electrical system parameters at the time of fault and date and time at which fault .occurred.
The power supply for the ETU is derived from the current transformer (110). The power supply (121) generates the necessary voltage for the signal conditioning circuit (123), the microcontroller (101) and others peripherals. The power for the

display namely E-Paper display (116) and the LCD display (315) is derived from the power supply (121).
The controller (101) also monitors the electrical parameters measured by the trip unit and displays the system parameters/ electrical parameters on display devices, preferably LCD (115) or OLED (117) of the output console in case there is no tripping and the electrical power is available for operating these display devices, LCD (115) or OLED 117 of the output console.
As the circuit breaker trips in case of an electrical fault, the circuit breaker isolates itself from rest of the power system and there is no electrical power available for operating the display devices, LCD (115) or OLED (117) of the output console. The display devices such as the LCD (115) and the OLED (117) require power to display the cause of the trip and other essential information pertaining to circuit breaker tripping. Accordingly, the display devices, LCD (115) or OLED 117 of the output console fail to display the cause of trip in the absence of the electrical power and are ineffective. The present invention uses an Electronic flexible paper based display or E-paper display (116) that gets electronically "printed" and enables viewing of contents thereon using reflected light, thereby continuously displaying the contents electronically "printed" thereon without requiring continuous supply of electrical power. More specifically, as the E-paper display (116) receives a display actuation command corresponding to measurements performed by the trip unit, a charge is held at appropriate pixel, such storage of charges at appropriate pixels define a scheme of pixels stored with charges to mimic the appearance of ordinary ink on paper, thereby facilitating the display of content. As a circuit breaker trips due to an electrical fault, the E-paper display (116) holds charge in its pixel to retain the scheme pixels stored with charges, as long as the E-paper display (116) is refreshed using an electrical signal. It means, once values displayed on the E-paper display (116) can remain displayed on the E-paper display (116) for a long duration, until another electrical pulse is applied to erase or refresh the contents being displayed on the E-paper display (116). The E-paper display (116) used in a

circuit breaker to display the cause of trip and electrical parameters at the time of fault.
Figure 2 illustrates examples of different contents displayed on the E-paper display for providing information pertaining to circuit breaker tripping under different circumstances. The E-paper display (116) displays information such as system parameters measured by a trip unit in case no fault condition is detected and no tripping occurs as is illustrated in screen 213 of Figure 2b. The E-paper display (116) displays information even after the electrical power from a current transformer is disrupted due to the circuit breaker getting tripped. For example, the E-paper display (116) displays information like nature of the electrical fault that caused tripping, e.g. due to overload as displayed in screen 211 or due to short circuit as displayed in screen 212. The E-paper display (116) displays information like the date and time at which the circuit breaker tripped and the tripping parameters such as current and voltage.
Figure 3 illustrates flow diagram depicting the various steps followed by the display system 100 for displaying information pertaining to circuit breaker tripping. In accordance with an embodiment of the present invention, the E-display device (413) is mounted along with other display devices such as the (Organic Light Emitting Diodes) OLED (414) based display device and the Liquid Crystal Display (LCD) on a single unit. Figure 4 illustrates an E-paper display device (413) disposed along with at least one display devices of an output console for displaying information pertaining to circuit breaker tripping.
Advantages of the invention
The display system in accordance with the present invention for displaying information pertaining to circuit breaker tripping has several technical advantages including but not limited to the realization of:

• a display system that redundantly displays all the information pertaining to circuit breaker tripping such as the nature of the electrical fault that caused tripping, the date and time at which the circuit breaker tripped and the tripping parameters such as current and voltage;
• a display system that displays all information regarding circuit breaker tripping on one screen, thereby eliminating the need to navigate to different screens for accessing different set of information;
• a display system that continuously displays information pertaining to circuit breaker tripping without requiring continuous supply of electrical power and is operational even after tripping;
• a display system that assists the maintenance personnel to timely rectify the electrical fault by providing necessary information to the maintenance personnel in a easy to understand and readable format;
• a display system that enables the maintenance personnel to read the information displayed thereon from a wider viewing angle;
• a display system that is reliable;
• a display system that is easy to use;
• a display system that is economical;
• a display system that is sturdy, does not fail frequently and has longer service life;
• a display system that may be easily retrofitted and used with any of the conventionally known circuit breakers and trip units; and
• a display system that displays useful data required for ensuring proper maintenance and safety of the power distribution system.
Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the invention. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the invention as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the invention, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the invention. These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We Claim:
1. A display system for redundantly displaying information, said display system
comprising:
a controller functionally coupled to a trip unit and a circuit breaker, wherein said trip unit adapted to measure system parameters corresponding to current received from current transformer and perform calculations to determine threshold values of said system parameters, said controller adapted to detect a fault condition based on the measurements and calculations performed by said trip unit and issue a trip command to said circuit breaker, said controller further adapted to issue a display actuation command corresponding to measurements performed by said trip unit before issuing said trip command;
an output console comprising at least one display device and functionally coupled to said controller, said at least one display device adapted to derive electrical power from said current transformer and display system parameters measured by said trip unit in case no fault condition is detected and no tripping occurs; and
an E-paper display device functionally coupled to said controller and adapted to initially derives electrical power from said current transformer to electronically "print" and display information pertaining to circuit breaker tipping upon receiving said display actuation command from said controller, said E-paper display device adapted to continuously display said information pertaining to circuit breaker tipping even after said electrical power from said current transformer is disrupted due to said circuit breaker getting tripped, thereby facilitating redundant display of information at all times.
2. The display system as claimed in claim 1, wherein said controller is a Programmable Logic based Controller (PLC).
3. The display system as claimed in claim 1. wherein said at least one display device is a Liquid Crystal Display (LCD).

4. The display system as claimed in claim 1, wherein said display device is an (Organic Light Emitting Diodes) OLED based display device.
5. The display system as claimed in claim 1, wherein said display device is a Thin Film Transistor (TFT) based display screen.
6. The display system as claimed in claim 1, wherein said E-display device is mounted along with other display devices on a single unit.
7. The display system as claimed in claim 1, wherein said E-paper display device adapted to be refreshed by an electrical signal issued by said controller upon restoring of the electrical power supply to said controller after rectification of the electrical fault.