AC / DC integrated on-load tap-changer tester calibration device

Abstract

The invention discloses an alternating current and direct current integrated on-load tap-changer tester calibration device, which comprises an upper computer and a lower computer, and is characterized in that the upper computer is set to input a control instruction; the lower computer is in communication connection with the upper computer and is set to respond to the control instruction to verify the transition resistance, the transition time and the three-phase synchronism measurement performance of the transformer on-load tap-changer tester; the lower computer comprises a main control unit, each phase control unit and a power supply module, and the main control unit is connected with each phase control unit and is set to issue a control instruction from the upper computer to each phase control unit; each phase control unit is set to control the constant resistance function module or the resistor array combination to realize resistance change so as to simulate transition resistance and transition time and synchronously simulate a three-phase transition process; and the power supply module is used for supplying power to each unit in the lower computer. According to the invention, the problem that there is no device for verifying the on-load tap-changer tester in the prior art is solved.

Description

Technical Field

[0001] The invention relates to the technical field of on-load tap changer tester calibration, and more particularly to an AC / DC integrated on-load tap changer tester calibration device. Background Art

[0002] The transformer on-load tap changer is the only moving part connected to the transformer circuit, so the detection of on-load tap changers has attracted more and more attention. In the relevant regulations, it is required to check the parameters such as transition resistance, transition time, and action sequence of the on-load voltage regulator.

[0003] In view of the importance of transformer on-load tap-changers in substation operation, more and more power test instrument manufacturers in the domestic market have begun to manufacture transformer on-load tap-changer testers. In order to promote the standardization of such testers of different manufacturers, relevant departments have issued corresponding power industry standards and put forward corresponding requirements for the performance of such test instruments.

[0004] The publication number is CN101169474A, and the name is a transformer on-load tap changer tester calibration device, which includes a plurality of physical standard resistors and a plurality of switch switching devices, forming a resistance switching network, and the resistance switching network is electrically connected to a core controller, and is characterized in that: the physical standard resistor is a power-type precision resistor with a low temperature coefficient and low distribution parameters, and its accuracy is better than 100mΩ; the switch switching device is a power-type field effect tube with an ultra-low on-resistance, and its on-resistance is less than 10mΩ, and the switching speed is better than 1μs.

[0005] The publication number is CN204374399U, and the name is a calibration device for an on-load tap changer tester. A calibration device for an on-load tap changer tester comprises a touch screen (1), a control ARM module (2), a time reference module (3), a switching module (4), a resistor network (5), and an analog switch (6). The control ARM module (2) is respectively connected to the touch screen (1), the time reference module (3), the switching module (4), and the analog switch (6) through signal lines, and the switching module (4) is connected to the resistor network (5) through signal lines.

[0006] It can be seen that the following technical defects exist at present: The defect of single calibration function is that traditional calibration devices cannot meet the calibration requirements of both AC and DC test modes at the same time. Most devices on the market only support a single test mode (such as only supporting DC method or AC method), resulting in the need to configure multiple sets of equipment to complete the complete calibration, which significantly increases the equipment cost and operation complexity; The simulation accuracy of dynamic parameters is insufficient. The existing devices have the following problems when simulating two key dynamic parameters in the transition process (transition resistance value change and transition time sequence): the resistance switching uses mechanical relays, resulting in slow response speed (millisecond level) and contact jitter. The resistance value adjustment adopts extensive grading, which cannot achieve fine adjustment below 1%. The time control accuracy is limited by mechanical action delay, and it is difficult to achieve microsecond synchronization; Three-phase asynchronous simulation defects. The three-phase channels of traditional equipment have the following synchronization problems: there are differences in signal transmission delays in the control circuits of each phase, and there is a lack of a dedicated synchronization signal mechanism, which leads to a start time deviation of more than 100μs in the three-phase transition process, and insufficient B / C phase verification accuracy (resistance accuracy is only 5%), which cannot meet the latest industry standard requirements; Therefore, how to provide an AC / DC integrated on-load tap changer tester calibration device is a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0007] In view of this, the present invention provides an AC / DC integrated on-load tap changer tester calibration device, aiming to solve the technical problems of single calibration function defect, insufficient dynamic parameter simulation accuracy and three-phase asynchronous simulation defect.

[0008] In order to achieve the above object, the present invention adopts the following technical solution: A calibration device for an AC / DC integrated on-load tap changer tester comprises: an upper computer and a lower computer, wherein the upper computer is configured to input control instructions, wherein the control instructions include parameters that need to be set when calibrating the transition resistance, transition time and three-phase synchronicity measurement performance of the transformer on-load tap changer tester; the lower computer is connected to the upper computer for communication and configured to respond to the control instructions to calibrate the transition resistance, transition time and three-phase synchronicity measurement performance of the transformer on-load tap changer tester; the lower computer comprises: a main control unit, control units of each phase and a power module, wherein the main control unit is connected to the control units of each phase and configured to send the control instructions from the upper computer to the control units of each phase; the control units of each phase are configured to control a constant resistance function module or a resistor array combination to realize resistance change, so as to simulate the transition resistance, transition time and synchronously simulate the three-phase transition process; the power module is configured to supply power to each unit in the lower computer.

[0009] Preferably, each phase control unit includes an A-phase control unit, a B-phase control unit and a C-phase control unit, wherein the A-phase control unit, the B-phase control unit and the C-phase control unit all include an AC control module and a DC control module.

[0010] Preferably, the AC control module includes: a gas discharge tube, a varistor, a voltage transformer, a current transformer, a first high-voltage relay, a second high-voltage relay, a plurality of optocoupler relays and a plurality of resistors, wherein one end of the gas discharge tube is grounded and the other end is connected to the varistor; the voltage transformer is connected in parallel with the varistor and then connected in series with the current transformer; the current transformer is respectively connected to the first high-voltage relay and the second high-voltage relay, wherein the first high-voltage relay and the second high-voltage relay are connected in parallel; at least three groups of optocoupler relays and resistors connected in parallel are connected in series with the second high-voltage relay, wherein each group of optocoupler relays and resistors connected in parallel includes an optocoupler relay and a resistor; at least six groups of optocoupler relays and resistors connected in parallel are connected in series with the parallel circuit consisting of the first high-voltage relay and the second high-voltage relay.

[0011] Preferably, the DC control module includes: a first field effect tube, a second field effect tube, a precision resistor array and a correction resistor, wherein the gates of the first field effect tube and the second field effect tube are respectively connected to the controller of the DC control module; the drain of the first field effect tube is connected to the precision resistor array, and the drain of the second field effect tube is connected to the correction resistor; the source of the first field effect tube is connected to the source of the second field effect tube; and one end of the precision resistor array away from the first field effect tube is connected to one end of the correction resistor away from the second field effect tube.

[0012] Preferably, the lower computer also includes: an A-phase DC input interface, a B-phase DC input interface, a C-phase DC input interface, an A-phase AC input interface, a B-phase AC input interface, and a C-phase AC input interface, wherein the A-phase DC input interface is configured to connect the transformer on-load tap changer tester with the DC control module included in the A-phase control unit; the B-phase DC input interface is configured to connect the transformer on-load tap changer tester with the DC control module included in the B-phase control unit; the C-phase DC input interface is configured to connect the transformer on-load tap changer tester with the DC control module included in the C-phase control unit; the A-phase AC input interface is configured to connect the transformer on-load tap changer tester with the AC control module included in the A-phase control unit; the B-phase AC input interface is configured to connect the transformer on-load tap changer tester with the AC control module included in the B-phase control unit; and the C-phase AC input interface is configured to connect the transformer on-load tap changer tester with the AC control module included in the C-phase control unit.

[0013] Preferably, the lower computer also includes: indicator lights, wherein the indicator lights include: a power indicator light, an operation indicator light, a communication indicator light and a fault indicator light, wherein the power indicator light is configured to indicate the current power supply status of the power module; the operation indicator light is configured to indicate the current operation status of the lower computer; the communication indicator light is configured to indicate whether the communication between the upper computer and the lower computer is normal; and the fault indicator light is configured to indicate whether a fault occurs in each unit in the lower computer.

[0014] Preferably, the lower computer further includes: a power switch, a fan, a debugging port, a universal serial bus interface, a grounding post and a power socket; the lower computer is communicatively connected with the upper computer via the universal serial bus interface.

[0015] Preferably, the host computer runs control software, and the control software is used to input control instructions, wherein the control software includes a DC setting interface, an AC setting interface and a report display interface, wherein the DC setting interface is used to input control instructions when the transformer on-load tap changer tester and the lower computer are connected using the DC wiring method; the AC setting interface is used to input control instructions when the transformer on-load tap changer tester and the lower computer are connected using the AC wiring method; the DC setting interface and the AC setting interface both include: a menu bar, a waveform display area, a parameter setting area, an experimental operation area and a status bar; the report display interface is used to display the test results of calibrating the transformer on-load tap changer tester.

[0016] Preferably, the parameter setting area includes: a phase selection area, a waveform parameter setting area, a device under test test information setting area, a resistance representation mode setting area, a historically saved test scheme setting area, a startup item setting area, and a fan setting area, wherein the phase selection area is used to select the phase of the current operation; the waveform parameter setting area is used to set the parameter value sent to the lower computer; the device under test information setting area is used to fill in the test value of the device under test; the resistance representation mode setting area is used to select the resistance representation mode of different phases of the current test; the historically saved test scheme setting area is used to select a saved test as a shortcut solution; the startup item setting area is used to select the startup phase, and the startup item cannot be empty; the fan setting area is used to set whether the fan is started.

[0017] Preferably, the report display interface is provided with a report type selection control and a report generation control, wherein the report type selection control is used to set the type of the generated test report to be an AC test report or a DC test report; and the report generation control is used to generate a test report.

[0018] The above technical solution includes at least the following technical effects: The present invention discloses a calibration device for an AC / DC integrated on-load tap changer tester. Compared with the prior art, the present invention can calibrate and verify the measurement performances such as transition resistance, transition time, and three-phase synchronization of the mainstream (based on the constant current source principle) transformer on-load tap changer tester on the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0020] Figure 1 The present invention is a schematic structural diagram of an AC / DC integrated on-load tap changer tester calibration device.

[0021] Figure 2 The present invention is a schematic structural diagram of a front panel of an AC / DC integrated on-load tap changer tester calibration device.

[0022] Figure 3a It is a wiring diagram of the DC two-terminal method; Figure 3b It is a wiring diagram of a DC four-terminal method; Figure 3c It is a schematic diagram of an AC wiring method; Figure 4 It is a schematic diagram of the rear panel of an AC / DC integrated on-load tap changer tester calibration device according to an embodiment of the present application; Figure 5 This is a DC setting interface diagram in the control software of an AC / DC integrated on-load tap changer tester calibration device according to an embodiment of the present application; Figure 6 This is the schematic diagram of the AC control module for AC calibration of the on-load tap changer tester; Figure 7 This is a schematic diagram of a DC control module for DC calibration of an on-load tapchanger tester. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In order to better understand the embodiments of the present application, the technical terms involved in the embodiments of the present application are explained as follows: The transformer on-load tap changer (OLTC) is a device that can change the winding turns ratio when the transformer is running, that is, under load conditions. By adjusting the position of the tap, the OLTC can adjust the transformer output voltage, thereby maintaining the voltage stability of the power system.

[0025] Transition resistance refers to a temporary connection resistance set between contacts in order to limit the arc current generated during the switching process of the on-load tap changer. This resistance forms a loop between the new and old contacts, allowing the current to be smoothly transferred from one contact to another, thereby avoiding the damage to the equipment and the power grid caused by the high-voltage arc caused by the instantaneous opening or closing. The design purpose of the transition resistance is to ensure a safe and reliable switching process and minimize the impact on the power system.

[0026] Transition time refers to the time required from the start of the on-load tap changer to the completion of the entire switching process, which includes two key stages: Single-stage transition time: refers to the length of time from the separation of one contact to the full contact of the new contact. Total transition time: covers all related actions, that is, the time from the issuance of the start switching command to the completion of all necessary mechanical movements and finally reaching a new stable state.

[0027] Three-phase synchronization means that in a three-phase power system, when the on-load tapchanger is operated, the switching actions of the three different phases should occur as synchronously as possible. Ideally, all tapchangers should complete switching at the same time to maintain the balance of the power system. If there are significant differences in the actions between the three phases, it may cause unbalanced current, voltage fluctuations or even more serious faults. The assessment of three-phase synchronization usually involves checking whether the maximum time difference between the phases is within an acceptable range and whether the behavior of each phase during the transition is consistent. Good three-phase synchronization performance helps reduce the impact on the power grid and ensure the quality of power transmission.

[0028] In the related art, there is a lack of a device for calibrating an on-load tap changer tester. In order to solve this problem, an AC / DC integrated on-load tap changer tester calibration device is provided in an embodiment of the present application. The calibration device is a special device for calibrating and verifying the measurement performances such as transition resistance, transition time, and three-phase synchronization of the mainstream (based on the constant current source principle) transformer on-load tap changer tester on the market.

[0029] The verification device mainly includes the following functions: 1. The transition resistance and transition time measurement functions of the on-load tap changer tester can be verified. This device has a three-phase transition process simulation channel, which can simulate the resistance change time (transition time) while simulating the standard resistance value (transition resistance). The two main parameters of the simulated transition process (resistance value and time) can be easily traced. Because the transition time and transition resistance are a comprehensive performance, the actual transition time is affected by the switching time of the transition resistance. Since the relay switching time is usually several milliseconds and has great instability, MOS tubes are selected as the switching switches of the transition resistance. MOS tubes have the characteristics of small on-resistance and short response time.

[0030] 2. It can verify the three-phase synchronization measurement function of the on-load tap changer tester. This device has analog channels with A, B, and C phases electrically isolated from each other, and can synchronously simulate the three-phase transition process.

[0031] 3. This device is mainly suitable for on-load tap changer testers based on the constant current source test method; and when using this device to simulate transition resistance, transition time and other functions, the user needs to first distinguish the current direction of the constant current source of the instrument to be calibrated.

[0032] 4. The verification device consists of two parts: the upper computer and the lower computer. The two parts communicate through the Universal Serial Bus (USB) interface. The upper computer provides users with a friendly control interface in the form of PC human-computer interaction, which is used to select the verification content, method, parameters, etc. The lower computer is a specific component that responds to various command parameters of the upper computer and implements the verification work.

[0033] 5. The lower computer processor adopts advanced high-speed single-chip microcomputer, which has fast data processing speed, stable performance, rich control functions, and can respond to the upper computer instructions quickly and in real time; the lower computer adopts many precision components and core design schemes such as high-precision low-temperature drift non-inductive precision resistors, high-speed high-power switch tubes, multi-channel electrical isolation, multi-range AC and DC signal measurement in the realization of core functions. The design ideas of software and hardware are novel and highly targeted, and can calibrate the on-load tap changer tester based on the constant current source test scheme on the market. The following is a detailed description in conjunction with specific embodiments.

[0034] Figure 1 is a structural block diagram of an AC / DC integrated on-load tap changer tester calibration device according to an embodiment of the present application, such as Figure 1 As shown, the device includes: an upper computer 10 and a lower computer 12, wherein: The host computer 10 is configured to input control instructions, wherein the control instructions include parameters that need to be set when calibrating the transition resistance, transition time and three-phase synchronization measurement performance of the transformer on-load tap changer tester.

[0035] According to an optional embodiment of the present application, the host computer 10 may be a computer, a mobile terminal, a tablet computer, or the like.

[0036] The lower computer 12 is in communication connection with the upper computer 10 and is configured to verify the transition resistance, transition time and three-phase synchronization measurement performance of the transformer on-load tap changer tester in response to the control instruction.

[0037] The lower computer 12 includes: a main control unit 120, each phase control unit 122 and a power supply module 124, wherein: The main control unit 120 is connected to each phase control unit 122 , and is configured to send control instructions from the host computer 10 to each phase control unit 122 .

[0038] Each phase control unit 122 is configured to control a constant resistance function module or a resistor array combination to achieve resistance change, so as to simulate transition resistance, transition time, and synchronously simulate a three-phase transition process.

[0039] The core control component of the lower computer 12 is the single-chip minimum system (i.e., the above-mentioned main control unit 120), which communicates with the upper computer 10 through a USB interface and responds to user commands; the main control unit 120 issues user commands, and each phase control unit 122 controls the constant resistance function module (DC) or the combination of the resistor array (AC) to achieve resistance change through photoelectric isolation according to established requirements. Through the high-speed control and switching of the single-chip microcomputer, the purpose of simultaneously simulating the two important parameters (resistance and time) in the transition process can be achieved.

[0040] The entire lower computer 12 can simulate the transition process of the three channels A, B, and C, among which phase A can take into account the accuracy of both resistance and time parameters, and its accuracy meets the main technical indicators; phases B and C are mainly used to cooperate with phase A to perform three-phase synchronization calibration, so the resistance accuracy of the two phases is only designed to be 1%, while the time accuracy is the same as the phase A indicator.

[0041] The power module 124 is configured to supply power to each unit in the lower computer 12 .

[0042] In the embodiment of the present application, the multi-channel power supply module is used to provide mutually isolated working power supplies to each functional module in the lower computer 12.

[0043] The above-mentioned AC / DC integrated on-load tap changer tester verification device provided in the present application can calibrate and verify the measurement performances such as transition resistance, transition time, and three-phase synchronization of the mainstream (based on the constant current source principle) transformer on-load tap changer tester currently on the market.

[0044] According to an optional embodiment of the present application, each phase control unit 122 includes an A-phase control unit, a B-phase control unit and a C-phase control unit, wherein the A-phase control unit, the B-phase control unit and the C-phase control unit all include an AC control module and a DC control module.

[0045] The A-phase control unit includes an A-phase DC control module and an A-phase AC control module, the B-phase control unit includes a B-phase DC control module and a B-phase AC control module, and the C-phase control unit includes a C-phase DC control module and a C-phase AC control module.

[0046] Taking into account the mutual independence of the three phases of AC and DC, the lower computer 12 considers adopting a 1-with-6 mode, in which the main MCU (i.e., the main control unit 120) issues a synchronization model to ensure the synchronization of each phase. The main MCU and multiple slave MCUs (controllers in each AC and DC control module) realize data exchange through 485 communication and a dedicated synchronization signal.

[0047] Through the above design, strong independence and good interchangeability between modules can be achieved, which is conducive to equipment debugging and assembly.

[0048] Figure 6 This is the schematic diagram of the AC control module for AC calibration of the on-load tap changer tester. Figure 6 As shown, the AC control module includes: a gas discharge tube, a varistor, a voltage transformer, a current transformer, a first high-voltage relay ( Figure 6 S10 in), the second high voltage relay ( Figure 6 S11 in the figure), multiple optocoupler relays and multiple precision resistors (R1~R7, R9~R12, the symbol on the left of the resistor symbol is the resistor number, and the symbol on the right is the resistance value), wherein the AC_L symbol is connected to the output phase line terminal (phase A, phase B, phase C) of the AC on-load switch tester, and the AC_N symbol is connected to the output neutral line terminal of the AC on-load switch tester. One end of the gas discharge tube is grounded, and the other end is connected to the varistor; the voltage transformer is connected in parallel with the varistor and then connected in series with the current transformer; the current transformer is respectively connected to the first high-voltage relay and the second high-voltage relay, wherein the first high-voltage relay and the second high-voltage relay are connected in parallel; the optocoupler relay S9 and the resistor R11 are connected in parallel, the optocoupler relay S1 and the resistor R10 are connected in parallel, the optocoupler relay S2 and the resistor R9 are connected in parallel, and then the three groups of parallel-connected optocoupler relays and resistors are connected in series with the second high-voltage relay S11. Six groups of parallel-connected optocoupler relays and resistors (optocoupler relay S3 and resistor R2, optocoupler relay S4 and resistor R3, optocoupler relay S5 and resistor R4, optocoupler relay S6 and resistor R5, optocoupler relay S7 and resistor R6, optocoupler relay S8 and resistor R7) are connected in series with the parallel circuit consisting of the first high-voltage relay and the second high-voltage relay.

[0049] like Figure 6 As shown in the figure, the test signal input end is connected to the varistor and the gas discharge tube. When the input end has an overvoltage, it can protect the subsequent circuit. The AC signal is sampled by the current and voltage transformer, and the controller MCU detects the voltage and current signals through the AD. When the voltage or current signal is detected to be abnormal, the controller MCU controls the high-voltage relay to disconnect the circuit and prompts an abnormal alarm. The two-level protection of software and hardware can play a better protective role.

[0050] Taking into account the impedance of the real transformer on-load decomposition switch, the AC impedance uses two impedance levels of 10K and 50K. The impedance can be changed within the range of 1%-30% with an arbitrary value of 1% by controlling the on-off combination of the optocoupler relay.

[0051] Figure 7 This is the schematic diagram of the DC control module for DC calibration of the on-load tap changer tester, such as Figure 7 As shown, the DC control module includes: a first field effect tube ( Figure 7 Q1 in the second field effect tube ( Figure 7 Q2 in it), a precision resistor array and a correction resistor, wherein the gates of the first field effect tube and the second field effect tube are respectively connected to the controller of the DC control module; the drain of the first field effect tube is connected to the precision resistor array, and the drain of the second field effect tube is connected to the correction resistor; the source of the first field effect tube is connected to the source of the second field effect tube; and one end of the precision resistor array away from the first field effect tube is connected to one end of the correction resistor away from the second field effect tube.

[0052] like Figure 7 As shown, the DC signal sampling part uses resistor voltage division sampling, followed by the operational amplifier, and then enters AD sampling. The AD sampling result is transmitted to the controller MCU of the DC control module through the isolation interface.

[0053] The protection circuit performs the following two functions: (1) Overcurrent protection: The actual current is measured through a sampling resistor. When the current is too large, the hardware locks the overcurrent fault and disconnects the test circuit. After the fault is eliminated, the fault can be unlocked through software.

[0054] (2) Overvoltage protection: The actual voltage is measured through a sampling resistor. When the voltage is too high, the hardware locks the overvoltage fault and disconnects the test circuit. After the fault is eliminated, the fault can be unlocked through software.

[0055] Regarding the selection of key components, standard resistors (accuracy 0.1%, temperature drift 20ppm) can be customized according to technical requirements. Through the power switch circuit, the pre-designed power precision resistor array can be combined in different ways to obtain the required resistance value. The resistance value range is: 0.1Ω-40Ω.

[0056] The power switch uses the IRF4110 high-speed power field effect transistor with ultra-low equivalent on-resistance.

[0057] In addition, since the actual resistance is affected by factors such as the temperature drift of the standard resistance accuracy, the wire resistance and the on-resistance of the on-switch, a correction resistor needs to be introduced to ensure that the required transition resistance accuracy is achieved.

[0058] The waveform obtained by using the DC calibration method to test the transformer on-load tap changer is very different from the manufacturer's routine test waveform. The DC method test is limited by the test technology and technical capabilities, and the on-site tap changer test sometimes has problems such as the waveform cannot be interpreted.

[0059] The test voltage used in the transformer on-load tap changer test using the AC calibration method is relatively high, and there is no influence of the DC back-EMF jump of the on-load tap changer in the DC test. The measured waveform reflects the current flow state at every moment in the switching process and can clearly reflect its working process. The test waveform analysis can be used to detect poor contact defects of the transition switch and evaluate the switching process of the on-load tap changer.

[0060] According to another optional embodiment of the present application, the lower computer 12 also includes: an A-phase DC input interface, a B-phase DC input interface, a C-phase DC input interface, an A-phase AC input interface, a B-phase AC input interface, and a C-phase AC input interface, wherein the A-phase DC input interface is configured to connect the transformer on-load tap changer tester and the DC control module included in the A-phase control unit; the B-phase DC input interface is configured to connect the transformer on-load tap changer tester and the DC control module included in the B-phase control unit; the C-phase DC input interface is configured to connect the transformer on-load tap changer tester and the DC control module included in the C-phase control unit; the A-phase AC input interface is configured to connect the transformer on-load tap changer tester and the AC control module included in the A-phase control unit; the B-phase AC input interface is configured to connect the transformer on-load tap changer tester and the AC control module included in the B-phase control unit; and the C-phase AC input interface is configured to connect the transformer on-load tap changer tester and the AC control module included in the C-phase control unit.

[0061] Figure 2 is a schematic diagram of the front panel of an AC / DC integrated on-load tap changer tester calibration device according to an embodiment of the present application, such as Figure 2 As shown in the figure, Pa+, Pa-, Ca+, Ca- are A-phase DC input interfaces, Pb+, Pb-, Cb+, Cb- are B-phase DC input interfaces, and Pc+, Pc-, Cc+, Cc- are C-phase DC input interfaces.

[0062] Taking Pa+, Pa-, Ca+, Ca- (phase A DC) as an example, its function is to simulate the output terminals of DC transition resistance and transition time, and supports two-terminal and four-terminal measurements respectively.

[0063] Figure 3a This is a wiring diagram of a DC two-terminal method, such as Figure 3a As shown, when the measurement method of the on-load tap changer tester to be calibrated (hereinafter referred to as the tester to be calibrated) is the two-terminal method, the constant current source current output lead of the tester to be calibrated is connected to the Ca+ terminal, and the constant current source current input lead is connected to the Ca- terminal.

[0064] Figure 3b It is a wiring diagram of a DC four-terminal method, such as Figure 3b As shown, when the measurement method of the tester to be calibrated is the four-terminal method, the constant current source current output lead of the tester to be calibrated is connected to the Ca+ terminal, and its constant current source current input lead is connected to the Ca- terminal, and at the same time, its positive voltage measurement lead is connected to the Pa+ terminal, and its negative voltage measurement lead is connected to the Pa- terminal.

[0065] like Figure 2 As shown, La and Na are A-phase AC input interfaces, Lb and Nb are B-phase AC input interfaces, and Lc and Nc are C-phase AC input interfaces.

[0066] Taking La and Na (A-phase AC) as an example, its function is to simulate the output terminals of AC transition resistance and transition time. Figure 3c It is a schematic diagram of AC wiring method.

[0067] As some optional embodiments of the present application, the lower computer 12 also includes: an indicator light 125, wherein the indicator light 125 includes: a power indicator light, an operation indicator light, a communication indicator light and a fault indicator light, wherein the power indicator light is configured to indicate the current power supply status of the power module; the operation indicator light is configured to indicate the current operation status of the lower computer; the communication indicator light is configured to indicate whether the communication between the upper computer and the lower computer is normal; and the fault indicator light is configured to indicate whether a fault occurs in each unit in the lower computer.

[0068] The indicator light 125 includes a power indicator light, an operation indicator light, a communication indicator light, and a fault indicator light. The power indicator light includes two states: always off and always on, which is used to reflect the current power supply status; the operation indicator light has two states: flashing and stopped, flashing indicates that the device is operating normally, and stopping indicates that the device is abnormal; the communication indicator light flashes, indicating that the upper computer and the lower computer are communicating data; the fault indicator light has two states: always off and always on, always off indicates that the device is normal, and always on indicates a fault (overvoltage or overcurrent in any circuit of each AC or DC unit number will cause the fault light to be always on).

[0069] Figure 4 is a schematic diagram of the rear panel of an AC / DC integrated on-load tap changer tester calibration device according to an embodiment of the present application, such as Figure 2 and Figure 4 As shown, the lower computer 12 further includes: a power switch 121 , a fan 123 , a debugging port 126 , a universal serial bus USB interface 127 , a grounding post 128 and a power socket 129 .

[0070] In the embodiment of the present application, the lower computer 12 is communicatively connected to the upper computer 10 via a universal serial bus interface 127 .

[0071] USB is a standard interface technology for connecting computers and their peripheral devices. It was originally developed by Intel, Microsoft, Compaq, NEC, IBM and other companies in the mid-1990s, and has gradually become one of the most commonly used connections between personal computers and other electronic devices.

[0072] The main features of USB are as follows: Plug and Play: Supports hot-swap function, users can connect or disconnect devices without turning off the power.

[0073] Strong compatibility: One USB port can connect to multiple different types of devices, such as keyboard, mouse, printer, mobile hard disk, camera, etc.

[0074] Transfer rate: With the update of the version, the data transmission speed of USB has been continuously improved, from the initial 1.5 Mbps (USB 1.0) to the latest USB4 up to 40 Gbps.

[0075] Power supply capability: In addition to data transmission, USB can also provide power to connected devices. A standard USB port can provide 5V voltage and a certain amount of current. The specific value varies depending on the USB version.

[0076] In some other optional embodiments of the present application, the host computer 10 runs control software, which is used to input control instructions, wherein the control software includes a DC setting interface, an AC setting interface and a report display interface, wherein the DC setting interface is used to input control instructions when the DC wiring method is used to connect the transformer on-load tap changer tester and the lower computer 12; the AC setting interface is used to input control instructions when the AC wiring method is used to connect the transformer on-load tap changer tester and the lower computer 12; the report display interface is used to display the test results of calibrating the transformer on-load tap changer tester.

[0077] After ensuring that the wiring is correct, open the control software running on the host computer 10, set the basic information of the test or use the default value to conduct the test.

[0078] Figure 5 : is a DC setting interface diagram in the control software of an AC / DC integrated on-load tap changer tester calibration device according to an embodiment of the present application, such as Figure 5 As shown, the DC setting interface includes: menu bar, waveform display area, parameter setting area, experimental operation area and status bar.

[0079] It should be noted that the communication setting interface also includes: menu bar, waveform display area, parameter setting area, experimental operation area and status bar.

[0080] As some optional embodiments of the present application, the above-mentioned parameter setting area includes: a phase selection area, a waveform parameter setting area, a test information setting area for the device under test, a resistance representation setting area, a historical test plan setting area, a startup item setting area and a fan setting area, wherein the phase selection area is used to select the phase of the current operation; the waveform parameter setting area is used to set the parameter value sent to the lower computer; the test information setting area for the device under test is used to fill in the test value of the device under test; the resistance representation setting area is used to select the resistance representation method of different phases of the current test; the historical test plan setting area is used to select a saved test as a shortcut plan; the startup item setting area is used to select the startup phase, and the startup item cannot be empty; the fan setting area is used to set whether the fan is started.

[0081] The following is an introduction to the functions of each area in the DC setting interface.

[0082] 1. Menu Bar 1) Connection and exit function: When the device is not connected or disconnected, click Connect to connect the device; exit the application.

[0083] 2) Settings: Set the directory for saving data of the current test and the basic information of the current test.

[0084] 3) Detection method selection: including DC and AC detection methods.

[0085] 4) Report: Preview saved records and generate report documents 2. Waveform display area The three current ideal value waveforms are displayed separately: a single cycle waveform and a transition cycle number waveform.

[0086] 3. Parameter setting area 1) Phase selection area: Select the phase to be currently operated. Click three phases to operate all phases at the same time.

[0087] 2) Waveform parameter setting area: set the parameter values ​​to be sent.

[0088] 3) Test information setting area for the device under test: fill in the test value of the device under test.

[0089] 4) Resistance representation mode setting area: select the resistance representation mode for different phases of the current test.

[0090] 5) Historical saved test plan setting area: Select a saved test as a shortcut plan.

[0091] 6) Startup item setting area: Select the phase to be started. The startup item cannot be empty.

[0092] 7) Fan setting area: whether the fan is started (started by default).

[0093] 4. Experimental operation area 1) Save: Save the current parameter settings and test results.

[0094] 2) Parameter download: Load the setting parameters into the calibration device of the calibrator.

[0095] 3) Online: The online calibrator calibrates the device to establish the initial circuit. The first time you use it, you need to download the parameters before going online.

[0096] 4) Start: Start the transition process.

[0097] 5) Stop: Stop the transition process.

[0098] 6) Disconnection: The initial loop is disconnected, and the transition process simulation needs to be reconnected to establish the loop.

[0099] 5. Status Bar 1) Display current instrument status: instrument name.

[0100] 2) Display the current working directory: the directory where the test information is saved.

[0101] 3) Display working status: When used for the first time, it prompts "Not Ready". After the parameters are downloaded successfully, it enters the "Waiting to Start State". After clicking Start, it enters the "Running State". After the transition is completed, click Stop to re-enter the "Waiting to Start State".

[0102] After the experiment is over, click the "Save" button in the test operation button box to save the current settings and test results as a quick selection and report record for later tests.

[0103] According to an optional embodiment of the present application, the report display interface is provided with a report type selection control and a report generation control, wherein the report type selection control is used to set the type of generated test report to be an AC test report or a DC test report; and the report generation control is used to generate a test report.

[0104] This application uses MOSFET arrays to replace mechanical relays, shortens the resistance switching time to nanoseconds, designs a precision resistance network (0.1Ω step) and a digital correction algorithm to achieve a resistance control accuracy of ±0.5%, and innovatively adopts a 1-with-6 master-slave MCU architecture with a dedicated synchronization signal line to ensure that the three-phase transition start time deviation is <10μs. A three-level protection system (gas discharge tube + varistor + hardware fuse) is constructed, and intelligent control software is developed to achieve integrated operations of parameter setting, process monitoring, and report generation.

[0105] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0106] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An AC / DC integrated on-load tap changer tester calibration device, characterized in that: include: The upper computer and the lower computer, among which, The host computer is configured to input control instructions, wherein the control instructions include parameters that need to be set when verifying the transition resistance, transition time and three-phase synchronization measurement performance of the transformer on-load tap changer tester; The lower computer is connected to the upper computer in communication and is configured to verify the transition resistance, transition time and three-phase synchronization measurement performance of the transformer on-load tap changer tester in response to the control instruction; The lower computer includes: a main control unit, each phase control unit and a power supply module, wherein: The main control unit is connected to each phase control unit and is configured to send control instructions from the host computer to each phase control unit; The control units of each phase are configured to control the constant resistance function module or the resistor array combination to realize resistance change, so as to simulate the transition resistance, transition time and synchronously simulate the three-phase transition process; The power supply module is configured to supply power to each unit in the lower computer.

2. The AC / DC integrated on-load tap changer tester calibration device according to claim 1, characterized in that: Each phase control unit includes an A-phase control unit, a B-phase control unit and a C-phase control unit, wherein the A-phase control unit, the B-phase control unit and the C-phase control unit all include an AC control module and a DC control module.

3. The AC / DC integrated on-load tap changer tester calibration device according to claim 2, characterized in that: The AC control module includes: a gas discharge tube, a varistor, a voltage transformer, a current transformer, a first high-voltage relay, a second high-voltage relay, a plurality of optical coupler relays and a plurality of resistors, wherein: One end of the gas discharge tube is grounded, and the other end is connected to the varistor; The voltage transformer is connected in parallel with the varistor and then connected in series with the current transformer; The current transformer is connected to the first high-voltage relay and the second high-voltage relay respectively, wherein the first high-voltage relay and the second high-voltage relay are connected in parallel; At least three groups of the photocoupler relays and the resistors connected in parallel are connected in series with the second high-voltage relay, wherein each group of the photocoupler relays and the resistors connected in parallel includes one photocoupler relay and one resistor; At least six groups of the photocoupler relays and the resistors connected in parallel are connected in series with a parallel circuit consisting of the first high-voltage relay and the second high-voltage relay.

4. The AC / DC integrated on-load tap changer tester calibration device according to claim 2, characterized in that: The DC control module includes: a first field effect tube, a second field effect tube, a precision resistor array and a correction resistor, wherein: The gates of the first field effect transistor and the second field effect transistor are respectively connected to the controller of the DC control module; The drain of the first field effect tube is connected to the precision resistor array, and the drain of the second field effect tube is connected to the correction resistor; The source of the first field effect transistor is connected to the source of the second field effect transistor; One end of the precision resistor array away from the first field effect transistor is connected to one end of the correction resistor away from the second field effect transistor.

5. The AC / DC integrated on-load tap changer tester calibration device according to claim 2, characterized in that: The lower computer also includes: an A-phase DC input interface, a B-phase DC input interface, a C-phase DC input interface, an A-phase AC input interface, a B-phase AC input interface, and a C-phase AC input interface, wherein: The A-phase DC input interface is configured to connect the transformer on-load tap changer tester and the DC control module included in the A-phase control unit; The B-phase DC input interface is configured to connect the transformer on-load tap changer tester with a DC control module included in the B-phase control unit; The C-phase DC input interface is configured to connect the transformer on-load tap changer tester and the DC control module included in the C-phase control unit; The A-phase AC input interface is configured to connect the transformer on-load tap changer tester and the AC control module included in the A-phase control unit; The B-phase AC input interface is configured to connect the transformer on-load tap changer tester and the AC control module included in the B-phase control unit; The C-phase AC input interface is configured to connect the transformer on-load tap changer tester and the AC control module included in the C-phase control unit.

6. The AC / DC integrated on-load tap changer tester calibration device according to claim 1, characterized in that: The lower computer also includes: indicator lights, wherein the indicator lights include: a power indicator light, a running indicator light, a communication indicator light and a fault indicator light, wherein: The power indicator light is configured to indicate the current power supply status of the power module; The operation indicator light is configured to indicate the current operation status of the lower computer; The communication indicator light is configured to indicate whether the communication between the upper computer and the lower computer is normal; The fault indicator light is configured to indicate whether a fault occurs in each unit in the lower computer.

7. The AC / DC integrated on-load tap changer tester calibration device according to claim 1, characterized in that: The lower computer also includes: a power switch, a fan, a debugging port, a universal serial bus interface, a grounding post and a power socket; The lower computer is connected to the upper computer through the universal serial bus interface.

8. The AC / DC integrated on-load tap changer tester calibration device according to claim 1, characterized in that: The host computer runs control software, and the control software is used to input the control instructions, wherein: The control software includes a DC setting interface, an AC setting interface and a report display interface, wherein: The DC setting interface is used to input the control instruction when the transformer on-load tap changer tester and the lower computer are connected by a DC wiring method; The AC setting interface is used to input the control instruction when the transformer on-load tap changer tester and the lower computer are connected by an AC wiring method; The DC setting interface and the AC setting interface both include: a menu bar, a waveform display area, a parameter setting area, an experimental operation area, and a status bar; The report display interface is used to display the test results of calibrating the transformer on-load tap changer tester.

9. The AC / DC integrated on-load tap changer tester calibration device according to claim 8, characterized in that: The parameter setting area includes: phase selection area, waveform parameter setting area, device under test test information setting area, resistance representation mode setting area, historical save test scheme setting area, startup item setting area and fan setting area, wherein: The phase selection area is used to select the phase of the current operation; The waveform parameter setting area is used to set the parameter value sent to the slave computer; The device under test test information setting area is used to fill in the test value of the device under test; The resistance representation mode setting area is used to select the resistance representation modes of different phases in the current test; The historical saved test plan setting area is used to select a saved test as a shortcut plan; The startup item setting area is used to select the startup item, and the startup item cannot be empty; The fan setting area is used to set whether the fan is started.

10. The AC / DC integrated on-load tap changer tester calibration device according to claim 8, characterized in that: The report display interface is provided with a report type selection control and a report generation control, wherein: The report type selection control is used to set the type of the generated test report to be an AC test report or a DC test report; The report generation control is used to generate the test report.

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