FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Hand Held Test Kit for Circuit Breaker Trip Units to Simulate Three Phase Current and Three Phase Voltage Fault Conditions"
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
Electrical & Automation North Wing, Gate 7, Level 0, Powai Campus, Saki Vihar Road, Mumbai 400 072, INDIA
3. PREAMBLE TO THE DESCRIPTION:
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Hand Held Test Kit for Circuit Breaker Trip Units to Simulate Three Phase Current and Three Phase Voltage Fault Conditions
Field of invention
This invention relates a hand held simulation test kit for circuit breaker trip units, and more particularly, it relates to a hand held simulation test kit to simulate three phase current and three phase voltage fault conditions.
Background of the invention
Trip units are basically used to provide protection and control for circuit breaker under fault conditions. The function of protection trip unit is to cause prompt discontinuation of service in presence of a short circuit, or when it starts to operate in any abnormal manner that might cause damage or otherwise interfere with the effective operation of the rest of the system.
The known testing methods for trip unit are basically known as primary injection testing. Wherein the current transformer are used to provide analog signals in proportion to the input power lines. These signals are evaluated with different protection algorithm to check for fault conditions. If a fault condition exists the trip unit gives a signal to the tripping mechanism which is an electromechanical flux shift device or trip solenoid. This solenoid in turn opens the breaker contacts thus discontinuing the supply to further loads and providing protection against faults. The test equipments and sources needed to perform these tests are very expensive, complicated and humongous. It is not always possible to have these setups at the installation site or substations. Also the wiring is very cumbersome and time consuming.

Accordingly, there exists a need to provide device which overcomes drawbacks of the prior art.
Object of the invention
An object of the present invention is to provide a simulation kit which does not require any external power to energies the trip solenoid which is used to open the breaker when a valid signal is given by trip unit during fault condition
Another object of the present invention is to provide a simulation kit which is used as a calibrating device during production of the protection and control units.
Brief description of the drawing
Figure 1 shows a hand held simulation kit for testing the trip units for circuit breakers, in accordance with the present invention;
Figure 2 shows a connection of the hand held simulation kit with a trip unit which is mounted on the breaker in the panel; and
Figure 3 shows a block diagram of a hand held simulation kit, 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 microcontroller based hand held simulation kit to verify the operation of trip units for circuit breakers. The simulation kit generates three phase current (R, Y, B) and three phase voltage signals (R, Y, B) with variable phase angle and frequency. The present invention is a battery operated device with an internal battery charger design and an organic LED display.
Referring now to figure 1 which shows a detailed diagram of hand held simulation kit (100) for testing the trip units for circuit breakers. The simulation kit (100) includes an enclosure (1) which is light weight and easy to handle. The simulation kit (100) is configured using a flexible overlay (2) with seven navigation keys and one test Start/Stop key. The simulation kit (100) has a built in organic LED (3) display for parameterization and metering. The simulation kit (100) is battery operated which can be charged using a built in power adaptor (4). It is connected to the trip unit using a simple interface cable (5). The simulation kit (100) also has a USB slot (6) for PC interface which is used during calibration of trip units during production. The test results and test scripts are stored in SD card (7) is used for further reference. The hand held simulation kit (100) has MODBUS interface for wired communication and Bluetooth for wireless communication with the trip.
Figure 2 shows a typical connection of the hand held simulation kit with the trip unit which is mounted on the breaker in the panel. The interface between the simulation kit (100) and the trip unit is a single cable which is used to inject three phase current and three phase voltage signals in the trip unit. The feedback for CT continuity, trip solenoid continuity and trip unit connectivity is also taken in the simulation kit (100) using this cable. The setting data from the trip unit is downloaded in the simulation kit (100) using this cable. The simulation kit (100) computes the fault signals according to the settings and injects them through the cable.

Referring now to figure 3, which depicts a block diagram of the hand held simulation kit (100). The hand held simulation kit (100) is powered using a set of rechargeable batteries (116). These batteries (116) are charged using by connecting a power adaptor (4) to the mains. The battery charging circuit (115) is inbuilt. The energy needed to operate the trip solenoid is also derived from these batteries. The power supply generator (118) needed to operate the microcontroller and rest of the circuitry by generating power from the battery. The simulation kit (100) also displays the charge status of the battery which gives a timely indication for charging.
The simulation kit has one master controller (114) and three slave controller (111), (112), (113) for three phases (R, Y, B). These slave controllers (111), (112), (113) are independent of each other. The slave controller (ill), (112), (113) does the processing and computation for generating each phase current and voltage signals. These signals are then fed to the trip units using the connection cable. The test scripts needed to test the trip units can be automatically generated or configured manually using a smart GUI with multifunctional keypad (120). There are also pre-configured test scripts for basic faults like overload, short circuit, instantaneous and earth fault. In addition to the basic current protection more advance voltage and frequency protections can also be simulated. These test scripts can be viewed on the Organic LED display (119).
Using the said simulation kit (100) it is possible to generate current fault signals from 0.1 to 16 times the rated current of the circuit breaker. Also it is possible to generate voltage fault signals from 0.1 to 1.5 times the rated voltage of the circuit breaker. The phase angle can be varied from 0 to 359 degrees with frequency variation of 44 to 66Hz.
The simulation kit (100) generates test reports with Rel / Brk ID, operator name, test result, trip time and date and time stamping. These records are stored in a

Secured Digital (SD) card (124) which is accessible for future reference. The preconflgured test scripts are also saved in this card. Thus the test scripts can be programmed independently on a computer and downloaded in this card and used.
In addition to the fault simulation iunction, the hand held test kit (100) also has a unique CT/ Rogowski coil continuity check (121) which ensures the electronic trip unit can actually open the breaker i.e. system meets trip requirement. This is a novel feature which facilitates safety to the user to check the correctness of the installation of current transformers the connectivity and continuity to avoid further accidents. The trip solenoid (122) which is an important interface between the trip units and the circuit breaker is also monitored for proper operation.
The simulation kit (100) communicates with the trip units using MODBUS (125) and Bluetooth (126) communication protocol. For auto testing the settings of the release is downloaded in the test kit and the test script is generated accordingly. The complete cycle of test can be done without manual intervention.
Further, the simulation kit is also used as a source for calibrating the trip unit during production. This is done using the USB slot (123) on the test kit. The test kit has an inbuilt temperature sensor (117) which monitors the temperature of the internal circuitry. It gives a message on the display if there is any nuisance and if the internal temperature exceeds the said reference.
The hand held simulation kit (100) described in the present invention is used to run secondary injection test with no complicates wiring. It is used to simulate all the basic faults viz. overload, short circuit, instantaneous and earth fault with no external equipments. The simulation kit does not require any external power to energise the trip solenoid which is used to open the breaker when a valid signal is

given by trip unit during fault condition. This kit is also used as a calibrating device during production of the protection and control units.
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 simulation kit for testing the trip units for circuit breakers, the simulation
kit comprising:
an enclosure for enclosing a circuitry;
a flexible overlay with plurality of navigation keys disposed on the enclosure;
a display disposed on the enclosure parameterization and metering;
a power adaptor for connecting with the power source for charging batteries;
a interface cable provided for connecting with the trip unit;
a USB slot configured on the enclosure for connecting USB device; and
a SD card slot configured on the enclosure for connecting the SD card and for storing the test results and test scripts.
2. The simulation kit as claimed in claim 1, wherein the circuitry comparing:
a slave controller R phase, a slave controller Y phase and a slave controller B phase independently process and compute to generate each phase current and voltage signals;
a master controller for controlling a slave controller R phase, a slave controller Y phase and a slave controller B phase;
a battery charging circuit with a battery for supping stored power to the master controller, a slave controller R phase, a slave controller Y phase and a slave controller B;
a temperature sensor for sensing temperature and sending the data to the master controller for analysis;
a power supply generator to generate electricity;
a OLED display is provided to display test script;
a keypad overlay to provide inputs to the controller;

a CT/Rogowski coil continuity check ensures the electronic trip unit opens the breaker to meet trip requirement;
a trip solenoid provides an interface between the trip units and the circuit breaker is also monitored for proper operation;
a Universal Serial Bus (USB) interface to connect USB for data transfer;
a Secured Digital (SD) card interface to connect a SD card for data transfer;
a modbus and a Bluetooth interface to communicate with the simulation kit remotely.