FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION (See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Method for Protection Setting change detection in Circuit breaker Trip Unit"
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. O. 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.

Method for Protection Setting change detection in Circuit breaker Trip
Unit
Field of the invention
The present invention relates to circuit breakers, and more particularly, to a method of detection of change in setting of a trip unit of the circuit breaker in absence of power.
Background of the invention
Circuit breakers have electronic trip units for protection from faults such as overload, short circuit, earth fault and the like. For setting the parameters of these fault levels, the trip units include either DIP switches or Rotary switches. These settings can be viewed or changed either in LIVE mode i.e. when current is passing through the circuit breaker and the trip unit is functional or OFF mode i.e. when no current is flowing through the circuit breaker, the circuit breaker is in OFF mode and the trip unit is not powered through any means. These settings gets effective immediately if the circuit breaker is in live mode or once the circuit breakers powers up.
In LIVE mode, there are various means of indication being provided to customer either through blinking of a LED, displaying it on panel display or remotely sending a signal on network about change in setting. But if the settings are changed in absence of power and once the power is restored, no indication is provided in any form to the customer about the change in setting. This is risky for certain critical application. Moreover, these setting change needs to be registered, at least, as in event for future action.
Currently available solution for the trip units with switches does not register switch settings either in LIVE mode or OFF mode. Once the circuit breaker

power ups, the settings are read from the switches directly and stored in random access memory (RAM) location which stores this value as long as power is available. Once the power is OFF, these values is lost and re-read once the power is restored. Hence, there is no means to detect the difference in settings before the power trip and after power is restored.
Accordingly, there is a need for customer to know whether the setting change has occurred in absence of power.
Objects of the invention
An object of the present invention to inform customer about off lines setting changes being done on a circuit breaker.
Summary of the invention
Accordingly, the present invention provides a method for protection setting change detection of a trip unit of a circuit breaker in absence of power. The method includes storing the protection setting value by the trip unit in non volatile memory such as a data flash/read only memory (ROM)/EEPROM or any other such memory device for holding data in absence of power. By storing the protection setting value in non volatile memory, the availability of the protection setting is ensured even when the power is OFF. Further, the method includes reading the protection setting value by the trip unit while the power supply is ON and holding the read protection setting value in random access memory (RAM). Furthermore, the method includes comparing the read protection setting value in the random access memory (RAM) with the stored value in non volatile memory. Finally, the method includes any one of performing LIVE mode activities by the trip unit such as protection function and indication if the compared values are identical and sending a signal by the trip unit if the read protection setting value does not match with stored protection

setting value, indicating change in setting during power OFF condition. The trip unit updates the non volatile memory with the new settings.
Brief description of the drawings
Figure 1 shows a algorithm for protection setting change detection, in accordance with the present invention.
Detailed description of the invention
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.
The present invention provides a method for detection of change in setting of the trip unit in absence of power. The method provides an alarm to a customer if there is any change made when the circuit breaker was OFF i.e. not powered through any means.
Referring now to figure 1, there is shown an algorithm for method (100) for protection setting change detection in a switch of a in circuit breaker trip unit, in accordance with the present invention. The switch is any one of a dual in-line package (DIP switch) and a rotary switch. The algorithm for the method (100) is provided in a processor of the trip unit.
The method (100) includes storing the protection setting value by the trip unit in a non volatile memory therein. By storing the protection setting value in non volatile memory, the availability of the protection setting is ensured when the power to the circuit breaker is OFF.

The method further includes reading the protection setting value by the trip unit while the power supply to the circuit breaker is ON. The read value are then held in random access memory (RAM) of the trip unit.
The method furthermore includes comparing the read protection setting value in the random access memory (RAM) with the stored value in the non volatile memory.
If the compared read protection setting value in the random access memory (RAM) and the stored value in non volatile memory are identical, then the trip unit performs LIVE mode activities such as protection function, indication and the like.
Further, if the compared read protection setting value in the random access memory (RAM) and the stored value in non volatile memory are not identical.the trip unit sends a signal to a customer indicating change in protection setting value during power OFF condition of the circuit breaker. In an embodiment, the signal is any one of the various signals known in art such as sound, visual and the like. Once the customer acknowledges the change in settings in the circuit breaker, then trip unit updates the non volatile memory with new settings and proceeds to perform LIVE mode activities as explained earlier.
Advantages of the invention
l.The protection setting values are stored in non volatile memory instead of RAM only which are available even in absence of power.
2. If anyone changes the protection setting values on the trip unit, then the method (100) provides means to detect the change which was not there earlier.

4. The method (100) also provides means to inform customer about change in setting in absence of power.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

We claim
1. A method for protection setting change detection in a switch of a
trip unit of a circuit breaker, the method comprising:
storing the protection setting value by the trip unit in a non volatile memory, wherein by storing the protection setting value in non volatile memory, the availability of the protection setting is ensured when the power is OFF;
reading the protection setting value by the trip unit while the power supply is ON;
holding the read protection setting value in random access memory (RAM);
comparing the read protection setting value in the random access memory (RAM) with the stored value in non volatile memory;
performing LIVE mode activities by the trip unit if the compared values are identical;
sending a signal by the trip unit if the read protection setting value does not match with stored protection setting value, indicating change in setting during power OFF condition; and
updating the non volatile memory by the trip unit with new settings.
2. The method as claimed in claim 1, wherein the signal send by the trip unit to the customer is any one of audio and visual signal.
3. The method as claimed in claim 1, wherein the new settings are undated in the switch by the trip unit once the customer acknowledges the changed setting.