The present invention relates, in general to transformer testing. The present invention in particular relates to automated test rig/ jig/ testing device. More particularly, the invention relates to an IoT based system to perform multiple tests with adjustable test sequence and test limits as well as to calibrate the testing device periodically.
DESCRIPTION OF THE RELATED ART:
[002] Power transformers play an important role in transmission and distribution of power. Power transformers form a critical link in the supply of power from the generation source to the users of the utility. Failure of a power transformer often means power loss to a number of consumers, therefore, transformer reliability is a very important parameter. In addition to transformer reliability, energy companies are typically very concerned about cost and efficiency of the power transformers.
[003] To meet the market demand, transformer manufacturers attempt to design reliable and efficient power transformers. Power transformer design, however, is a very complex process. There are probably hundreds of design parameters that affect the cost performance (e.g. reliability, efficiency, etc) of a transformer.
[004] Moreover, there are many manufacturing steps for a transformer, each of which could affect the transformer performance. For example, if a transformer is manufactured with a piece of equipment that is out of calibration, it may fail to meet a performance specification. Because of the complexity of transformer design and manufacture, it is very difficult to troubleshoot the root because of a test failure and to determine a solution to address the test failure.
[005] Transformers are tested by their manufacturers and the generation and transmission authorities. The typical test parameters may include polarity, phase relation, core loss, load loss, and transformer ratio.
[006] However, there is no universal testing procedure followed by the testing agencies. Different standards are followed and sometimes transformer manufacturers implement their own custom test sequences. Many times, the customer requires the manufacturer to follow a certain test sequence and with many different customers, changing test sequences after every order is not an easy task for the manufacturer's transformer testing facility. Moreover, different systems are typically needed to implement different tests.
[007] Automated testing devices to test the transformers according to a test program having a predetermined sequence of test instructions, are known. In other words, the known test devices execute a test program in fixed sequence of test instructions during the testing that cannot be varied with the requirements. For example, if the test program selects a transformer test which is programmed to first run a winding resistance test and then a voltage ratio test at a certain set of parameters, then each time the transformer test is selected, the winding resistance test is performed first and the voltage ratio test is performed second.
[008] Thus, the sequence of test instructions is arranged such that a sequence of test instructions specifying a winding resistance test is listed before a sequence of test instructions specifying a voltage ratio test. The disadvantage of having a test program with a fixed sequence of test instructions is that the user does not have the flexibility of editing or creating a particular sequence to optimize the transformer test program.
[009] 2024/DEL/2014 relates to a system for non-contactably perform multiple tests of major operating parameters of transformers with adjustable test sequence and test limits the current transformers each having at least a primary winding and a secondary winding, the system comprising: an alternating current (AC) power source configured to supply an AC signal; a variable AC voltage controller to generate a desired voltage; a switch coupled between a micro - controller and the transformer to switch power to the controller responsive to the control commands; a plurality of individual wires for connection to transformer terminals, an alphanumeric keyboard to change the imputed value of test parameters, an optional ampere meter for sine wave transformers to power the power backup systems, a display device, a visual indicator, a pneumatic linear movable fixture, a communication port, a data logger with input means, a biometric or password protection device, a RTC connected to the controller and a switch mode power supply with fixed DC voltage and current to measure such as but not limited to winding resistance and HV test of the transformers, wherein the system is enabled to create sequences by the user for testing a transformer and store these sequences for future use; select the testing limits of the transformer to be tested including the upper - lower limits of turns/ winding ratio, no load current of all windings on particular voltages, DC resistance of all windings, no-load factor, no load power consumption, ratio error and phase angle error in the steady state, errors in boundary conditions, and verification of the design for low leakage flux, and generate new transformer profile by assigning date relating to transformer capacity both lower and upper testing limits and the test sequence.
[010] 2204/DEL/2011 relates to a system for performing high rate discharge capacity of batteries, comprising a load assembly, a control unit, a mechanical assembly and a communication means, wherein the load assembly constitutes a transistor assembly and provides discharge path to the system and consists of N transistors, an X-power transistors, the N-transistors connected in parallel configuration to carry (NxY) Amp current, wherein said each of said N-transistors carries current of Y Amp, wherein said X power transistors connected in parallel and including at least one driver transistor; and wherein said control unit controls the discharge current through the transistor assembly.
[011] US5889385A discloses a method for equalizing the charge among a plurality of series-connected energy storage devices in a set of said energy storage devices, comprising the steps of applying at least one charging pulse to said set, said charging pulse providing a series charging current, said series charging current having an amplitude and a duration, each said energy storage device receiving a portion of said charging pulse which is independent of a portion of said charging pulse received by any other energy storage device; applying a plurality of depolarization pulses to said set, said depolarization pulses each drawing a discharge current having an amplitude and a duration, said depolarization pulses being separated from each other by rest periods, each said rest period having a duration; for each said energy storage device, measuring the voltage of said energy storage device at a pre determined point within a said rest period preceding a predetermined said depolarization pulse; for each said energy storage device, measuring the voltage of said energy storage device at a pre determined point within a said rest period following said predetermined depolarization pulse; for each said energy storage device, determining a voltage difference between said voltage at said pre determined point within said preceding rest period and said voltage at said predetermined point within said following rest period.
[012] US3622857A discloses a rapid battery charging circuit comprising transmission means operable to transmit direct current pulses to a battery through a continuously operable electrical connection; a discharge path including an active element having a control terminal for applying the discharge path; and a discharge means for periodically electrically applying said discharge path across said battery without interrupting said electrical connection between said battery and said transmission means, said discharge means including a series voltage divider combination of four impedance elements connected across said battery; a capacitor connected across three of said impedance elements, with one side of the capacitor connected to the negative terminal of said battery; a series combination of a silicon-controlled rectifier and a resistor connected in parallel with said capacitor, with the resistor connected in the cathode circuit of the silicon controlled rectifier; means for connecting the gate of the silicon-controlled rectifier to the middle junction of the four impedance elements; a source of voltage of opposite polarity and of the same phase as the direct current pulses applied to said battery, and means for connecting said source to the junction of the two impedance elements between the gate of said silicon controlled rectifier and the terminal of the battery to which one side of the capacitor is connected; and means for connecting the cathode of said silicon-controlled rectifier to the control terminal of said active element.
[013] US3559025A discloses apparatus for rapidly charging a battery from a source of charge current pulses, said apparatus comprising a first controllable switch connected between the source and the battery; a second controllable switch connected across the battery; means for sensing the terminal voltage of the battery; means for sensing the flow of charge current through the battery; and means responsive to both sensing means for controlling the operation of said second controllable switch for discharging the battery.
[014] US4257002A discloses an apparatus for storing the circuit conditions existing between a plurality of end points established by the conductors of a known multi conductor harness and for comparing the circuit conditions existing between a plurality of points established by the conductors of a multi conductor harness to be tested to said circuit conditions of the conductors of said known multi conductor harness, said apparatus comprising: storage means for storing information representative of circuit conditions existing between said plurality of points established by the conductors of said known multi conductor harness; testing means for applying a signal to said plurality of points; detection means responsive to said signal for determining the existence of circuit conditions existing between said plurality of points; transfer means responsive to said detection means for transferring information representative of said circuit conditions of the conductors of said known multi conductor harness to said storage means; comparing means for comparing the circuit conditions existing between said plurality of points established by the conductors of said known harness with the circuit conditions existing between the plurality of points established by the conductors of said harness to be tested; control means for selectively operating said transfer means when the conductors of said known harness are connected to said points and for selectively operating said comparing means when the conductors of said multi conductor harness to be tested are connected between said points wherein said comparing means further comprises means responsive to said detection means for comparing the end points being tested by said testing means with the interconnections in said storage means having the same end points further comprising signaling means responsive to said comparing means for indicating the result of the comparing operation performed by the comparing means further comprising means responsive to operation of said detection means for selecting a portion of said data in said storage means associated with the said one of said end points; said comparing means comparing the contents of said portion of said data with the end point being scanned by said testing means when said detection means was engaged and he connectors are of the 50 point type.
[015] US6788077B2 discloses a system for testing a transformer comprising: a processor comprising a transformer test engine adapted to execute a user-changeable transformer test sequence comprising a plurality of user-selected tests and instructions in a user-defined order of execution; a controller coupled to the processor to output control commands; a switcher coupled between the controller and the transformer to switch power to the controller responsive to the control commands; and a metering system coupled between the transformer and the processor to receive measurements from the transformer and provide the measurements to the processor further comprising a memory device coupled to the processor for storing transformer specifications; a memory device for storing the transformer test sequence and a test sequence editor to allow customization of the transformer test sequence and an input device for receiving commands into the test sequence editor, wherein the transformer test sequence comprises a plurality of test instructions and associated parameters.
[016] US6798211B1 discloses a fault locator system for an underground residential distribution power cable system which includes a distribution loop, the fault locator system comprising: means for providing a pulse signal which approximates an impulse; means for applying the pulse signal as a first pulse signal to the distribution loop when no power is applied to the distribution loop and there is no fault in the cable and for measuring a response of the distribution loop to estimate a first impedance transfer function of the distribution loop to the pulse signal when no fault exists; means for applying the pulse signal as a second pulse signal to the distribution loop when power is applied and the fault exists and for measuring a response of the distribution loop to estimate a second impedance transfer function of the distribution loop to the pulse signal when the fault exists; means for defining a third impedance transfer function as a function of the first impedance transfer function; means for adjusting the third impedance transfer function to minimize differences between the second impedance transfer function and the adjusted third impedance transfer function; and means for adjusting parameters of a pre determined parametrically adjustable impedance model to minimize differences between the third impedance transfer function and the parametrically adjustable model, whereby the adjusted parameters indicate the location of the fault and a fault distance indicator (FDI), locates a fault in a power line by modeling pulses of reflected travelling wave signals which are generated from electrical arcs that occur as a result of the fault.
[017] A new online method based on leakage flux analysis for the early detection and location of insulating failures in power transformers: Application to remote condition monitoring by Cabanas MF, Melero MG, Pedrayes F, Rojas CH, Orcajo GA, Cano JM, Iglesias JG, Nuno F. IEEE transactions on power delivery; 22.07.2007 talks about an online analysis of transformer leakage flux as an efficient alternative procedure for assessing machine integrity and detecting the presence of insulating failures during their earliest stages. A 12-kVA 400-V/400-V power transformer was specifically manufactured for the study. A finite-element model of the machine was designed to obtain the transient distribution of leakage flux lines in the machine’s transversal section under normal operating conditions and when shorted turns are intentionally produced. Very cheap and simple sensors, based on air-core coils, were built in order to measure the leakage flux of the transformer, and nondestructive tests were also applied to the machine in order to analyze pre and post failure voltages induced in the coils.
[018] US Patent No.6,788,077 discloses a system and method for creating, editing, and/or executing a test program for testing a transformer. The system includes an input that allows the user to select the desired test instructions and preexisting sequences of test instructions to create or edit a test program having a sequence of test instructions. The processor executes the test program by generating commands that are performed in a predetermined order.
[019] Publication No. CN 202330594 describes an intelligent distribution transformer terminal computer programmed test platform, characterized in that it comprises a control computer and the test bench, the test bench equipped with a standard three-phase power source, three-phase standard table, a small test signal terminal interface board, a pulse signal generator, power test module, the DC output module and a plurality of communication interfaces test bench, test bench control computer via the communication interface, respectively, with the three phase standard power source, three-phase standard meter, power test module, the DC output module, pulse signal generator and small signal interface board to connect the terminal test, three-phase power source with a standard three phase standard meter connections.
[020] Publication No. CN 102830311 teaches a transformer testing system for automatically testing a transformer. The transformer testing system comprises a conveying system and a detection system.
[021] Publication No. CN 101382575 provides an automatic test system of an electronic transformer, which comprises a machine cabinet, a high-low voltage switching box, a programmable high-voltage tester, a computer, a displayer, a programmable alternating current power supply, a keyboard, an indicator light, a loading plate and a relay that are sequentially connected from down to up and arranged in the machine cabinet, the high-low voltage switching box is installed with a position sensor; the automatic test system of the electronic transformer obtains test data by using the computer for controlling a dada acquisition card, calculates the test data by using the computer, and then obtains the result for judging the good and bad of the tested product; the computer has DAQ and DIO serial ports.
[022] Publication No. CN 2601406 suggests a computer control transformer test bench for testing the performance of a transformer and technical energy saving. The device is composed of a computer display, a keyboard, a printer worktable and a cabinet, wherein the cabinet is provided with the industrial computer, a DC resistance test module and a transformation ratio test module, and is composed of a loss test module and a loss test control box.
[023] Publication No. CN 203117358 describes an intelligent tester for secondary polarity of a four-star-shaped voltage transformer. The intelligent tester for secondary polarity of a four-star-shaped voltage transformer automatically determines whether secondary side wiring of the four-star-shaped voltage transformer is correct and the error type, and is rapid and accurate in test, convenient to operate, and direct in display, thereby substantially improving work efficiency, and reducing potential safety hazards.
[024] Publication No. CN 102749607 discloses an electronic current transformer test platform comprising a PC (Personal Computer) test system, a comprehensive data interface, wiring terminals, current display screens, a current regulation turn knob, a power switch, a trolley body and universal wheels, wherein the PC test system is mounted on a side face of the trolley body, the comprehensive data interface is located at a side face of the trolley body, the current display screens are arranged at middle positions of the upper face of the trolley body, the wiring terminals are arranged at one side of the upper face of the trolley body, and the current regulation turn knob and the power switch are arranged at the other side of the upper face of the trolley body.
[025] Publication No. CN 101344566 describes a test apparatus and a test method used for testing the distortion of a coil of a power transformer. The apparatus comprises an upper computer, a test unit, a DDS sweeping a signal generator unit, a wide-frequency power amplifier unit and a power supply system.
[026] US Patent No. 5,264,799 teaches an apparatus for automatically testing the performance of a power transformer without requiring a testing operator repeatedly to disconnect-and-connect the power supply lines during the testing process so as to avoid the risk of high voltage electric shocks.
[027] Publication No. CN 203217023discloses a motor and transformer microcomputer integration test stand. The motor and transformer microcomputer integration test stand has functions of intelligent control and measuring, automatically completes functions of test data acquisition, calculating, storage and historical report check, automatic formation of a test report and printing, simplified a tedious wiring process in a test, effectively improves work efficiency and reduces an error ratio in the test.
[028] Publication No.CN 102565562 teaches a comprehensive testing device for an electrical test of a transformer. The whole device is provide with a set of working power supply, wherein a foreground processor of a central processing unit (CPU) system is used for the data acquisition work of three data acquisition systems and controls the work of a relay switching system; and a background computer finishes man-machine interaction work, manages data and outputs a testing report.
[029] Publication No. CN 103439682 describes a current transformer composite error testing technology and provides a portable current transformer composition error testing device and a method for testing a composite error of a current transformer by utilizing the portable current transformer composite error testing device.
[030] Reference may be made to prior non-patent literature entitled "TTRIOO handheld single phase turns ratio test set" by Megger Group Limited which talks about a handheld, robust, lightweight and battery operated instrument which tests turns ratio, phase displacement, excitation current, vector group, winding resistance and polarity. The device also has alphanumeric keyboard.
[031] Reference may be made to non-patent literature entitled "Technical & Testing equipment" by O'Hara Engineering that talks about a lightweight instrument for performing excitation, ratio, polarity and winding resistance tests on current transformers (CYs) as well as burden-impedance measurement.
[032] Reference may be made to known non-patent literature entitled "Multifunctional primary test system for substation commissioning and maintenance" by Omicron Electronics that talks about system for automated testing of power transformers such as testing of ratio, burden, polarity and winding resistance etc.
[033] Accordingly the prior art describe transformer testing devices that include multiple steps or involve different equipments. Also the testing device requires the transformer to be disposed into the device making it a time consuming and laborious job.
[034] A system for non-contactably perform multiple tests of major operating parameters of transformers with adjustable test sequence and test limits.
[035] The present invention provides a customized transformer rig/jig device whose testing limits and test sequence can be programmed by an authorized personnel and which is protected by the mean of an authentication system. Transformer testing rig provides the complete protection/isolation for any wrong connections.
OBJECTS OF THE INVENTION:
[036] It is therefore an objection of the invention to propose a system for non-contactably perform multiple tests of major operating parameters of transformers with adjustable test sequence and test limits.
[037] Another object of the invention is to propose a system for non-contactably perform multiple tests of major operating parameters of transformers with adjustable test sequence and test limits which is easy to operate.
[038] Yet another object of the present invention to propose a system for non-contactably perform multiple tests of major operating parameters of transformers with adjustable test sequence and test limits which is capable of testing a transformer with different winding configurations.
[039] Still another object of the present invention is to propose a system for non-contactably perform multiple tests of major operating parameters of transformers with adjustable test sequence and test limits which is enabled to test the no-load current, power including power factor of the transformer.
[040] A further object of the present invention is to propose a system for non contactably perform multiple tests of major operating parameters of transformers with adjustable test sequence and test limits which can be adjusted during the testing corresponding to the rating of transformers.
[041] A still further object of the invention is to propose a system for non-contactably perform multiple tests of major operating parameters of transformers with adjustable test sequence and test limits which is capable for current-controlled determination of characteristic of the transformers including the power supplies.
[042] Yet further object of the present invention is to propose a system for non-contactably perform multiple tests of major operating parameters of transformers with adjustable test sequence and test limits which eliminates substantial number of devices needed for testing of the transformers.
[043] Another object of the present invention is to propose a system for non-contactably perform multiple tests of major operating parameters of transformers with adjustable test sequence and test limits which simplifies the procedure of testing the transformers.
[044] Another object of the present invention is to propose a system for non-contactably perform multiple tests of major operating parameters of transformers with adjustable test sequence and test limits which is enabled to adjust the limits of testing parameters including testing sequence applicable to various types and capacities of transformers.
[045] Another object of the present invention is to propose a system for non-contactably perform multiple tests of major operating parameters of transformers with adjustable test sequence and test limits which can generate a testing profile for the transformer to be tested and maintain a record file.
[046] Another object of the present invention is to propose a system for non-contactably perform multiple tests of major operating parameters of transformers with adjustable test sequence and test limits which provides a protection to the testing rig of the testing system against connection - error and simultaneously suggests the desired connection.
SUMMARY OF THE INVENTION:
[047] The present invention relates to a system for non-contactably perform multiple tests of major operating parameters of transformers with adjustable test sequence and test limits which allows for automatic testing of different parameters of multiple types of transformers such as but not limited to polarity, no-load current, no-load power, no-load power factor including correctness of the winding ratio for variable AC voltage.
[048] In an embodiment of the present invention, the system incorporates a switching means which permits the windings of the transformer under test to be sequentially connected to a test rig/jig of the testing system.
[049] In another embodiment of the present invention, the system includes an alphanumeric input/output devices such as but not limited to a keyboard so that user can change inputted technical parameters as per rating of the transformer into the system.
[050] In yet another embodiment of the present invention, the user can set a lower and upper limit of turns/ winding ratio. No-load current of all windings on particular voltages, DC resistance of all windings, no-load power factor, no-load power consumption, ratio error and phase angle error in the steady state, errors in boundary conditions, and verification of the design for low leakage flux.
[051] In still another embodiment of the present invention, the order of execution of each test instructions are stored and the transformer test sequence is generated based on the order.
[052] In a further embodiment of the present invention, indications are provided to know the test status of the transformer i.e. pass, rejected or testing in progress.
[053] In a still further embodiment of the present invention, a display is provided to show the status of parameters of the transformer.
[054] In an yet further embodiment of the present invention, a communication interface is provided for local and remote monitoring of the system.
[055] In another embodiment of the present invention, a data logging and RTC is provided to know hour wise, current and daily date of transformer test rig/jig testing device.
[056] In yet another embodiment of the present invention, a user selection facility is provided to extract the data.
[057] In still another embodiment of the present invention, the system comprises separate wires which can be connected directly to the transformer terminals through clips which make it easier for testing in field conditions.
[058] In yet another embodiment of the present invention, a transformer testing profile can be generated which contains but not limited to upper lower limits, testing sequence by an authorized personnel.
[059] In yet another embodiment of the present invention, an authentication means is provided for example, a biometric device which also keeps the record.
[060] In yet another embodiment of the present invention, the system provides complete protection/isolation against wrong electrical connections at the end of the testing transformer or at end of the transformer test rig and also provides a solution/step to be taken to avoid wrong connections.
BREIF DESCRIPTION OF THE INVENTION
[061] It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments.
[062] Figure 1 illustrates an exemplary system in accordance with the present invention used for testing transformers;
DETAILED DESCRIPTION OF THE INVENTION:
[063] The present invention provides an IoT based system to perform multiple tests with adjustable test sequence and test limits as well as to calibrate the testing device periodically. The system comprises a controller with a switch coupled between controller and the device to be tested (8) to switch power to the controller responsive to the control commands. The user can set the test parameters at the remote server using hand held device. An IoT based central system with remote data logging characterized in that the said system is in communication with the controller of test device as well as the distributors wherein the distributors have limited access and the user can set the reference parameters at the central system using hand held device based upon need and usage (fig 1).
[064] The power analyzer calibrates the testing device periodically by measuring an electrical signal’s True RMS time period; voltage and current which is communicated to the central system which performs subsequent calculation and detects frequency cycles to provide reliable RMS periods during power conversion. An optional ampere meter is provided for sine wave transformers to power the power backup systems, a display device, and a visual indicator, a pneumatic linear movable fixture, a communication port.
[065] A RTC connected to the controller and a switch mode power supply with fixed DC voltage and current wherein the system is enabled to: create sequences by the user for testing a device and store these sequences locally using data logger as well as remotely using central server for future use; select the testing limits of the transformer to be tested including the upper - lower limits of the parameters.
[066] A device (8) that is to be tested is disposed between the switches (2) consists of a clamp and the controller (3). The testing rig/ jig/ testing system further includes separate wires which can be connected directly to the device to be tested (8) terminals through clips which eliminates the need to dispose the device (8) into the testing system.
[067] The switch (2) is coupled to a power supply (1) and provides power to the device (8) during the test. If the wires are connected to wrong terminals, the device (8) is protected by automatically switching the power off.
[068] The switch (2) is controlled by the controller (3) to provide power from the power supply (1) to the device (8) being tested. The measured data is transferred to the controller (3) which is communicated to the IoT based central system which records the data along with product reference for future usage.
[069] The device test program is customized by user at IoT based central server using hand held device by creating or editing a new sequence of test instructions from individual test instructions or other preexisting sequences of test instructions. A user is able to create sequences for testing a transformer and store these sequences at IoT based central system for future use. The user customizes the testing limits of the device to be tested, using authorized person’s hand held device is able to change the limits. The central server records the person who changes the limits along with date time and old values. The central system restores factory default setting automatically. User is able to create new device profile with assigning transformer capacity, testing limits both lower and upper, test sequence.
[070] In an embodiment; the proximity sensors are following:
a) Proximity sensor 1 senses the input battery entering.
b) Proximity sensor 2 senses the battery is in position under the top clamping cylinder.
c) Proximity sensor 3 senses that the battery going out of the main conveyor or is in the right position for rejection cylinder to push it to the rejection conveyor.
d) Proximity sensor 4 senses the number of batteries in the rejection conveyor and senses the accumulation of batteries in rejection conveyor.
e) Reed switches are magnetic switches which are connected on every cylinder. These switches sense the position of the cylinder either home position or extended position.
[071] The system has variable selection of current value at which battery will discharge. The voltage trends are represented in graphical form to show when the battery is discharging, barcodes are generated for accepted batteries only.
[072] Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention.

WE CLAIM:

1. An IoT based system to perform multiple tests with adjustable test sequence and test limits as well as to calibrate the testing device periodically comprises
? a controller (2) with a switch coupled between controller and the device (1) to be tested to switch power to the controller responsive to the control commands; wherein user can set the test parameters at the remote server using hand held device;
? an IoT based central system (1A) with remote data logging characterized in that the said system is in communication with the controller of test device as well as the distributors wherein the distributors have limited access and the user can set the reference parameters at the central system using hand held device (1B) based upon need and usage;
? power analyzer (1C) calibrate the testing device periodically by measuring an electrical signal’s True RMS time period; voltage and current wherein the said power analyzer is controlled by the controller (2);
? an optional ampere meter for sine wave transformers to power the power backup systems;
? a pneumatic linear movable fixture;
? a RTC (7) connected to the controller and a switch mode power supply with fixed DC voltage and current wherein the system is enabled to: create sequences by the user for testing a device and store these sequences locally using data logger (8) as well as remotely using central server for future use; select the testing limits of the transformer to be tested including the upper - lower limits of the parameters.

2. The IoT based system to perform multiple tests with adjustable test sequence and test limits as well as to calibrate the testing device periodically, as claimed in claim 1, wherein the power analyzer (1C) calibrates the testing device periodically by measuring an electrical signal’s True RMS time period; voltage and current which is communicated to the central system which performs subsequent calculation and detects frequency cycles to provide reliable RMS periods during power conversion.
3. The IoT based system to perform multiple tests with adjustable test sequence and test limits as well as to calibrate the testing device periodically, as claimed in claim 1, wherein the device test program is customized by user at IoT based central server using hand held device by creating or editing a new sequence of test instructions from individual test instructions or other preexisting sequences of test instructions.
4. The IoT based system to perform multiple tests with adjustable test sequence and test limits as well as to calibrate the testing device periodically, as claimed in claim 1, wherein the user is creates sequences for testing a transformer and stores these sequences at central system for future use.

5. The IoT based system to perform multiple tests with adjustable test sequence and test limits as well as to calibrate the testing device periodically, as claimed in claim 1, wherein the user customizes the testing limits of the device to be tested, using authorized person’s hand held device is able to change the limits.