KR20030020001A - Portable transformer tester - Google Patents

Abstract

PURPOSE: A portable transformer tester is provided to increase convenience by employing a high-speed microprocessor for processing a signal. CONSTITUTION: A system management module(21) is comprised of a hardware system and a software system. The hardware system comprises an operating switch panel, a power operating circuit, a power supply unit, a CPU(Central Processing Unit), a digital signal input circuit, a digital signal output circuit, a voltage/current detection circuit, an analog signal input circuit, a gain control circuit, and peripheral devices. A digital signal acquisition module(22) comprises a scanning routine and a filter to sample a switch contact signal of the operating switch panel as a code value. An analog signal acquisition module(23) comprises an ADC(Analog-to-Digital Conversion) operating program and a filter to sample and performs a digital conversion on voltage and current signals of the voltage/current detection circuit. A measuring module(24) processes data acquired by the analog signal acquisition module(23). A database(25) stores testing/measuring data in the form of a file. An MMI(Main-Machine Interface)(26) interfaces a portable transformer tester with a user. A digital signal output module(27) generates a digital signal for opening/closing an electronic switch.

Description

Portable Transformer Tester

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable transformer tester for testing the characteristics of power transformers and transformers, and more particularly to the field of manufacture of instrumentation and test equipment for testing electrical characteristics of power equipment.

This is an indicator of the characteristics of transformers and transformers.The parameters that affect the stability of the power supply and the protection control of the power system are polarity, turns ratio, excitation current, short circuit current and phase difference angle or phase angle displacement. The characteristics test of transformers is conducted by combining various measuring instruments in the construction, repair, inspection and testing of power facilities at KEPCO, large-capacity power supply, heavy electric manufacturers, power equipment builders, and research institutes. Although the need for a portable transformer characteristic tester is recognized, it is postponing the research and development at the instrument manufacturer for the demand and economic reasons.

Portable transformer tester and related technologies / products include BIDDLE TTR Transformer Turn Ratio Test Set (AVO International, USA), BIDDLE THREE-PHASE TTR Transformer Turn Ratio Test, Set (AVO International), Portable Current Transformer Tester (Patent No. 0206655, 1999.02. 09, patent holders Korea Electric Power Corporation, inventor Han Hong-seok et al., And each description is shown in Table 1.

As described in the table below, the AVO International's BIDDLE TTR and BIDDLE THREE-PHASE TTR are portable testers for power system installations, but they measure the turns ratio and phase difference of the transformer. It has only functions, and there are problems such as economic and maintenance due to expensive foreign products. The portable current transformer tester can test the characteristics of the current transformer, but cannot be applied to a transformer. Therefore, it is necessary to develop a field tester that can measure the characteristics of the transformer such as winding ratio, short circuit current, polarity, phase difference angle, excitation current, voltage in one test.

TABLE 1

The technical development of the portable transformer tester, which is easy to use, inexpensive and easy to maintain, is the object of the present invention. The features and functions of the present invention are as follows:

-Portable measuring instrument for transformer and transformer characteristics test of high voltage power system equipment

-Real time measurement and test based on microprocessor for high speed signal processing

-Implementation of pager measurement technique based on DFT operation

-Auto-ranging function

-Test / measurement items: turns ratio, short circuit current, polarity, phase difference, excitation current, transformer winding voltage

-Test result processing: display LCD, recording S-RAM, communication RS232 / 485, printing dot matrix

-Setting: Transformer installation information, environmental information, menu type setting

Output: 220V (single phase) / 380V (three phase), 0 ~ 10V 60Hz (three phase)

-Operation: Output ON / OFF, test voltage switching, test mode switching, printing, setting key operation

Power supply: 3 phase 220V, 3A

Environment: 0 ℃ ~ 50 ℃, 0 ~ 90% (Non-condensing)

-PC monitoring software program: data upload / download, data retrieval and printing

1 is a hardware system configuration of a portable transformer tester according to the present invention.

1 is a software system configuration of a portable transformer tester according to the present invention.

1 is a flow chart of the operation of the portable transformer tester according to the present invention.

<Explanation of symbols for the main parts of the drawings>

01: Plug Receptacle Panel 02: Power Control Circuit

03: operation switch panel 04: DC power supply

05: Central processing unit (CPU) 06: Bus (Bus)

07: voltage current detection circuit 08: digital signal input circuit

09: analog signal input circuit 10: digital signal output circuit

11 gain control circuit 12 display device drive circuit

13 key controller 14 communication controller

15: printer controller 16: memory (RAM / SRAM)

21: system management module 22: digital signal acquisition module

23: analog signal acquisition module 24: measurement module

25: Database 26: MMI (Man-Machine Interface) Module

27: digital output signal generation module 28: drive module

31: System Initialization 32: Select Settings

33: Select test mode 34: Select output voltage

35: output selection 36: processing routine

37: Key Operation 38: Test Mode Switch

39: output voltage switching switch 40: output switch operation

41: Print switch operation 42: Print selection

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram of a hardware system of a portable transformer tester according to the present invention.

In Fig. 1, 01 is a plug socket panel, 02 is a power control circuit, 03 is a control switch panel, 04 is a DC power supply, 05 is a central processing unit (CPU), 06 is a bus (Bus), 07 is a voltage and current detection circuit. , 08 is digital signal input circuit, 09 is analog signal input circuit, 10 is digital signal output circuit, 11 is gain control circuit, 12 is display device driver circuit, 13 is key controller, 14 is communication controller, 15 is printer controller, 16 denotes a memory (RAM / SRAM), respectively.

In FIG. 1, the plug socket panel 01 is a panel on which a power input socket, a voltage output socket, and a voltage input socket, which are three-phase plug sockets for electrical connection between a portable transformer tester and an external device, are mounted. The input socket is a plug socket for connecting an external three-phase AC power supply and a power supply control circuit (02), and the voltage output socket has a test voltage output from the power supply control circuit (02) via a voltage current detection circuit (07). A plug socket for connecting to the transformer primary terminal, the voltage input socket is a plug socket for connecting the voltage input from the transformer secondary terminal under test to the voltage current detection circuit (07), each plug socket is a three-phase circuit It has three terminals for each phase, one neutral / ground terminal and four terminals in total.

In FIG. 1, the power control circuit 02 is a manual switch of a power circuit for opening and closing the power flowing from the power input socket of the plug socket panel 01, and an overcurrent protection circuit to protect the power and the device by blocking an overload. , Power display lamp for displaying power status, output circuit electronic switch for opening and closing test voltage output, test voltage switching electronic switch for switching test voltage level, and test voltage regulator for continuously adjusting test voltage As a circuit comprising a, output a test voltage to the voltage current detection circuit 07 and supplies the internal power to the DC power supply (04).

In FIG. 1, the operation switch panel 03 is an output switch which is an ON / OFF switch for generating an open / close signal of the electronic switch for the test voltage output circuit of the power supply control circuit 02, and the test voltage of the power supply control circuit 02. A test voltage switching switch which is an ON / OFF switch for generating an open / close signal of a level switching electronic switch, and an automatic return type push button switch for switching the test mode of the portable transformer tester of the present invention to a winding ratio test or a short test mode. A mode switch, a print switch which is an auto-return push button switch for controlling the operation of the printer embedded in the portable transformer tester of the present invention, and the test voltage is continuously changed when the position of the test voltage change switch is 'LOW'. A panel comprising a control knob of a voltage regulator, which is a switch panel for operating the portable transformer tester of the present invention.

In FIG. 1, the DC power supply device 04 is an AC / DC converter, and when the manual power switch of the power control circuit 02 is input, power is applied to supply DC power to the internal power supply and the peripheral device including the CPU 05. Device.

In FIG. 1, the CPU 05 as the central processing unit is a DSP (Digital Signal Processor) as a microprocessor for high-speed signal processing, and includes a system management program, a test / measurement algorithm, and an I / O interface (Input / Output Interface (MMI) and Man-Machine Interface (MMI) programs are built-in, and various interfaces and peripheral devices and mutual data / connected to the busbar 06 for communicating data and instructions between the CPU and peripheral devices of the processor system. It receives commands and manages the system according to the user's instructions through MMI.

In FIG. 1, the voltage current detection circuit 07 is connected to the output voltage circuit of the power supply operation circuit 02, and the voltage detection transformer and current detection current transformer for detecting the voltage current applied to the primary side of the transformer under test. A resistance voltage divider connected to a voltage input circuit connected to a voltage input socket of the plug socket panel 01 to detect a secondary voltage of a transformer under test, and an electrical circuit between an output circuit of the transformer, a current transformer, a voltage divider and a microprocessor input circuit. A signal isolation circuit for isolation, a filtering circuit for removing noise from the output signal of the signal isolation circuit, and an amplifier, a resistor array for adjusting amplification gain and gain for automatically adjusting the amplification gain of the signal according to the signal level. The control circuit 11 includes an amplifying circuit to which an auto-ranging circuit including a decoder which decodes an output code value is added. An analog circuit that converts the detected signal into a signal of 0~5V level and outputs it to the analog signal input circuit (09).

In FIG. 1, the digital signal input circuit 08 receives a contact state output signal such as a test voltage output switch, a test voltage level switch, a test mode switch, or a print switch of the operation switch panel 03, and then performs logic isolation after signal isolation. It includes a photo-coupler and a logic circuit that converts the signal, and provides information to the CPU by digitizing the contact signal and placing it on the bus line 06.

In FIG. 1, the analog signal input circuit 09 receives a voltage signal of 0-5V level, which is an output signal of the voltage current detection circuit 07, and digitizes it by means of an analog-to-digital converter (ADC) on the bus line 06. It is an analog / digital conversion circuit that provides information to the CPU by placing it.

In FIG. 1, the digital signal output circuit 10 includes an optoelectronic device that converts a digital code value input through a bus line 06 into a logic signal and insulates a signal, and a relay that converts a logic signal into a contact signal. The controller converts the code value commanded by the CPU into a contact signal to trigger the electronic switch of the power supply operation circuit.

In Fig. 1, the gain control circuit 11 is composed of an optoelectronic device which converts the amplification degree setting value input through the bus 6 into a logic value and insulates the signal, and realizes auto-ranging of the voltage current detection signal level. It is a logic circuit which outputs an amplification degree setting signal to the decoder of the voltage current detection circuit 07.

1, a display device driver circuit 12 for driving a liquid crystal display device for testing and setting value display, a key controller 13 for controlling a keypad for inputting setting data, and an external device are connected to each other as peripheral devices. Communication controller 14 for receiving, printer controller 15 for controlling an internal printer for printing test results, semiconductor memory 16 capable of power failure compensation for storing test and setting data, and other peripheral devices. As a timer (Clock) and LED for indicating the status of the portable transformer tester system of the present invention, the peripheral devices are the same as the computer peripherals generally used, so the detailed description is omitted.

2 is a software system configuration of a portable transformer tester according to the present invention.

2, 21 is a system management module, 22 is a digital signal acquisition module, 23 is an analog signal acquisition module, 24 is a measurement module, and 25 is a database. Base), 26 denotes an MMI module, 27 denotes a digital output signal generation module, and 28 denotes a peripheral drive module.

In FIG. 2, the system management module 21 includes a main program including a scheduler that manages a processing sequence and a processing time of each software module constituting the portable transformer tester software system according to a user input program. Each software module has an organic relationship with each other, and serves as a system manager that enables the test and measurement to be performed as shown in the flowchart of FIG. 3.

In FIG. 2, the digital signal acquisition module 22 distinguishes the contact signal of the operation switch inputted into the digital signal input circuit 08 of FIG. 1 from the chattering and noise of the contact according to the scheduling of the system management module. Is a software program configured to include a software filter and a scanning routine for reading a contact signal as a digital code value. The system management is performed by updating the corresponding variable value of the software program indicating the operation switch contact state to the acquired new value. The module 21 is used to provide information for the schedule progress and to be used as a logic input on the operation processing flowchart of FIG. 3.

In FIG. 2, the analog signal acquisition module 23 converts the amount of detection of voltage and current input to the analog signal input circuit 09 of FIG. 1 into digital code values according to the scheduling of the system management module. This is a software program that includes a moving average filter. It is a software filter for removing noise from the digital signal that is the driver and the output of the ADC. It is a software program that includes a moving average filter. By updating, the measurement module 24 is used as raw data input to various test and measurement algorithms.

In FIG. 2, the measurement module 24 is a software program for processing raw data acquired by the analog signal acquisition module 23 and displaying them as physical quantities. The basic algorithm is based on the Phaser Measurement Method, which calculates and calculates the effective value of voltage, current, power, reactive power, frequency, and phase.

A pager measurement module for calculating a voltage and current phaser represented by a real part and an imaginary part obtained by using a cyclic recursive discrete fourier transformation (DFT) algorithm from instantaneous values of voltage and current which are raw data;

The actual effective value for measuring the primary and secondary winding voltage, excitation current, short circuit current, etc. of the transformer under test by calculating by the recursive form formula of the effective value definition formula from the instantaneous values of the raw data voltage and current ( Real rms Value) measurement module;

A fundamental wave RMS measurement module obtained by dividing a square root of a sum of squares of a real part and a square of an imaginary part obtained by the pager measurement module by two square roots;

A winding ratio measuring module using a voltage comparison method obtained as a ratio of the primary winding voltage of the transformer under test to the secondary winding voltage obtained from the fundamental wave RMS measurement module;

A phase difference angle measurement module for obtaining a phase of a transformer under test using a real part and an imaginary part obtained in the phaser measurement module, and obtaining a phase difference angle which is a phase angle between two phasers;

A polarity measuring module for determining the polarity or the polarity by evaluating the phase difference angles of the primary and secondary winding voltage phasers of the transformer to be tested obtained from the phase difference angle measuring module; And

When the level of the winding voltage, excitation current, short circuit current, etc. of the test target transformer obtained by the actual effective value measurement module is lower than the reference level input by the user, the amplification gain of the voltage current detection circuit 07 of FIG. 1 may be increased. It is a software measurement program including an input signal gain module for controlling the gain control circuit 11.

In FIG. 2, the database 25 stores setting and test / measurement data in a file format in the internal memory, and uploads data such as test date, test item, and setting item to the MMI module 26 according to the inquiry contents. It is a portable data management system.

In FIG. 2, the MMI module 26 is a soft control program for an interface between a portable transformer tester and a user of the present invention. The MMI module 26 includes a key scan module, setting data, and measurement data for transmitting key operation details to the system management module 21. And a display module which is input to the display device driving module 12 of FIG. 1 and displayed on the display device.

In FIG. 2, the digital output signal generation module 27 is a logic program for generating a digital signal for opening and closing the electronic switch of the power supply operation circuit 02 according to the switch operation of the operation switch panel 03 of FIG.

In FIG. 2, the driving module 28 includes a communication module for driving a communication port according to a communication protocol, a printing module for driving a printer, a display module for driving a display device, a key module for driving a keypad, and the like. A software program for driving a peripheral device, which is configured to be, is a general one supplied with the peripheral device, and thus description thereof is omitted.

3 is a flowchart of the operation of the portable transformer tester according to the present invention.

3, 31 is system initialization, 32 is setting selection, 33 is test mode selection, 34 is output voltage selection, 35 is output selection, 42 is processing routine, 37 is key operation, 38 is test mode switching switch and 39 is output Voltage switching switch, 40 denotes output switch operation, 41 denotes print switch operation, and 36 denotes print selection.

In FIG. 3, the system initialization 31 is a routine for warming-up of system components and initialization of system program variables when the portable transformer tester is powered on.

In Fig. 3, the setting selection 32 is a conditional statement. If YES, the setting of the test environment and the setting of the test operation data are performed by the key operation 37 of the key controller 13 of Fig. 1; .

In Fig. 3, the test mode selection 33 is a conditional sentence. If YES, the test mode switching switch 38 of the operation switch panel 03 of Fig. 1 is switched to the winding ratio test or the short circuit test, and if NO, the process proceeds to the next routine.

In FIG. 3, the output voltage selection 34 is a conditional sentence. If YES, the output voltage switching switch 39 of the operation switch panel 03 of FIG. 1 is switched to HIGH or LOW, and if it is LOW, the operation switch panel 03 of FIG. ) And the voltage adjustment knob to adjust the desired voltage. If NO, go to the next routine.

In Fig. 3, the output selection 35 is a conditional sentence. If YES, the test is started by turning on the output switch operation 40 of the operation switch panel 03 of Fig. 1 and applying a test voltage to the transformer under test. Go to the routine.

In FIG. 3, the processing routine 36 is the software program module of FIG. 2, the system management module, the digital signal acquisition module, the analog signal acquisition module, the measurement module, the database, the MMI module, and the digital output signal generation module. In addition, the peripheral device driving module and the like are routines to be performed. When the test is completed by satisfying the test condition input from the setting routine 32, the system is placed in a standby state.

In Fig. 3, the print selection 42 is a conditional statement. If YES, the print switch operation 41 of the operation switch panel 03 of Fig. 1 is performed to print the test result by the built-in printer. To fulfill;

The infinite loop from the setting selection 32 to the printing selection 42 is performed as long as the power during the transformer test of the present invention is not OFF.

According to the development of the manufacturing technology / product of the portable transformer tester according to the present invention, it becomes possible to use the instrument for transformer test / measurement in the institution / entity related to the manufacture, installation, operation, maintenance, and inspection of ultra high voltage power system equipment. For example, the technical and economic effects expected to result in the acquisition of relevant metrology technologies in the instrumentation work body are:

ㆍ Technical Effect

-Development of portable measuring instrument for transformer and transformer characteristics test of high voltage power system

-Real-time measurement technology based on microprocessor for high speed signal processing

-Secure electricity measurement technology by pager operation based on DFT technique

-Measurement of winding ratio, polarity, phase difference, excitation current, short circuit test, winding voltage measurement technology

-Implementation of auto-ranging function

-The output voltage can be selected and the continuous variable can be applied so that the test voltage can be applied to either winding of the transformer primary side or secondary side.

-Localization of the environment and simple operation (minimization of setting items, menu type operation)

Economic effect

-KEPCO Electric Power Corporation (Power Generation Substation, Electric Power Management Office, Korea Electric Power Research Institute, etc.), Heavy Electric Manufacturers, Electric Power Equipment Companies, Large Electric Power Customers, Research Institutions

-Import substitution: $ 750,000 annually ($ 250,000 × 30 units / year based on AVO's TTR introduction price)

ㆍ Other Effects

-Diversified varieties for customer service at instrument makers

Claims (2)

A portable instrument manufacturing technique for testing the turns ratio, polarity, excitation current, phase difference and short circuit current characteristics of a voltage level converter such as a power transformer and a transformer; A plug socket panel equipped with a socket for electrical connection between a portable transformer tester and an external device of the present invention, and an operation switch panel equipped with an operation switch; A power supply operation circuit including a circuit switch and a voltage regulator such as a power supply circuit, a test voltage output circuit, and a test voltage switching circuit connected to the plug socket panel; A power supply device connected to a power circuit breaker of the power control circuit for supplying power to the internal components of the portable transformer tester of the present invention; A CPU including a microprocessor in which a software program of the portable transformer tester of the present invention operated by power supply of the power supply device is embedded; A digital signal input circuit comprising a photo coupler and a logic circuit for converting a switch contact state signal of the operation switch panel into a code value and providing the same to the CPU; A digital signal output circuit comprising a switching semiconductor element and a logic circuit for opening and closing the electronic switch driving circuit of the power supply operation circuit according to a command of a CPU; A voltage current detection circuit including a test voltage output and an input circuit voltage, a current detector, a signal insulation circuit, a filtering circuit, an amplifier circuit, and an auto-ranging circuit connected to the socket of the plug socket panel; An analog signal input circuit including an ADC and a sample-and-holder for converting an output signal of the voltage and current detection circuit into a digital signal; A gain control circuit including a logic circuit converting the amplification degree setting value of the CPU into a logic signal and outputting the logic signal to a decoder of an auto-ranging circuit of the voltage and current detection circuit; A hardware system including a display device driving circuit connected to the CPU bus, a key controller, a communication controller, a memory device capable of power failure compensation, a peripheral device such as a clock and an LED; And A system management module including a main scheduler, a system scheduler for managing a processing sequence and a processing time of a portable transformer tester component of the present invention; A digital signal acquisition module including a scanning routine and a filter for sampling the switch contact signal of the operation switch panel to a code value; An analog signal acquisition module including an ADC drive program and a filter for sampling and digitizing the voltage and current signals of the voltage and current detection circuit; A measurement module based on a phasor measurement technique for calculating the amount of electricity by processing the data acquired by the analog signal acquisition module; A database for storing setting and test / measurement data in an internal memory in the form of a file according to the scheduling of the system management module and for retrieving the stored data; MMI module including a key scan module and a display module for the interface between the portable transformer tester and the user of the present invention; A digital output signal module for generating a digital signal for opening and closing the electronic switch of the power control circuit according to the switch operation of the operation switch panel; Portable transformer tester characterized in that the software system comprising a peripheral drive module, such as a communication module for printing the portable transformer tester and an external device of the present invention, a printing drive module, a display device drive module, a keypad drive module. The apparatus of claim 1, wherein the measurement module comprises: a pager measuring technique for measuring a phase of voltage and current by processing data acquired by the analog signal acquisition module with a cyclic recursive discrete fourier transform (DFT) algorithm; A fundamental wave rms measurement technique for measuring fundamental wave rms values of voltage and current from a voltage and current phaser of the phaser measuring module; A winding ratio measuring technique using a voltage comparison method for comparing the fundamental wave effective value voltages of the primary and secondary windings of the transformer under test of the fundamental wave effective value measuring module; A phase angle measuring technique for obtaining a phase angle from the pager; A phase difference measuring technique for calculating a phase angle difference between two signals of the phase angle measuring module; A polarity measuring method by comparing phases of the transformer primary and secondary windings of the phase angle measuring module; And The data acquired by the analog signal acquisition module is processed by a cyclic algorithm in which the effective value definition equation is modified to measure an electric quantity by applying a technique such as an actual effective value measuring technique for calculating winding voltage, excitation current, and short circuit current. Portable transformer tester.