Integrated mutual inductor detector

Abstract

The utility model relates to the technical field of transformer detection, and discloses an integrated mutual inductor detector which comprises a box body, one surface of the box body is used as a panel, and the panel is provided with a display screen, a CT line bank, a PT line bank, a power switch button and a selection switch button set. An electromagnetic voltage transformer detection board, a capacitor voltage transformer detection board and a current transformer detection board are installed in the box body. Data acquisition ports of the electromagnetic voltage transformer detection board, the capacitor voltage transformer detection board and the current transformer detection board are respectively connected with a CT connector bar or a PT connector bar through contacts of corresponding relays, and power supply ports are respectively connected with power supply wiring holes used for accessing a power supply through the contacts of the corresponding relays and a power supply switch. And the signal input and output ports are respectively connected with the display screen through contacts of the corresponding relays. According to the utility model, the detection convenience is improved.

Description

Technical Field

[0001] This utility model relates to the field of transformer testing technology, specifically to an integrated instrument transformer tester. Background Technology

[0002] Current transformers (CTs) and voltage transformers (PTs) play a very important role in power system relay protection and metering. Their performance and quality directly affect whether the power system can operate safely and stably, whether the relay protection devices can work properly, and the accuracy of metering and billing.

[0003] Traditional voltage and current transformers require connection to a standard current transformer, standard voltage transformer, current booster, voltage booster, current and voltage load box, voltage regulation control box, and high-current conductors for testing. This is very inconvenient when conducting on-site testing, as it involves carrying multiple instruments and equipment.

[0004] To facilitate portability, some portable voltage and current transformer testers have appeared on the market for on-site online testing of transformers. However, when testers go to the field, they have to carry two test devices, one for testing voltage transformers and the other for testing current transformers. This is not only inconvenient for testers to carry, but also inconvenient for movement and on-site operation. Utility Model Content

[0005] This utility model provides an integrated instrument transformer tester, which integrates the circuit boards of existing current transformer testers, electromagnetic voltage transformer testers, and capacitor voltage transformer testers into one box, making it convenient to carry out on-site testing of metering devices.

[0006] This utility model is achieved through the following technical solution:

[0007] An integrated instrument transformer tester includes a housing, one surface of which serves as a panel. The panel includes a display screen for showing test results, a CT terminal block for connecting test leads to test current transformers, a PT terminal block for connecting test leads to test voltage transformers, a power switch button for activating the tester, and a set of selection switches for selecting the instrument transformer testing board. The housing houses an electromagnetic voltage transformer testing board, a capacitive voltage transformer testing board, and a current transformer testing board, and includes data acquisition ports for these boards. Each of the three circuits is connected to the CT terminal block or PT terminal block via the contacts of the corresponding relays. The power supply ports of the electromagnetic voltage transformer detection board, the capacitor voltage transformer detection board, and the current transformer detection board are connected to the power supply connection hole via the contacts of the corresponding relays and the power switch. The signal input and output ports of the electromagnetic voltage transformer detection board, the capacitor voltage transformer detection board, and the current transformer detection board are connected to the display screen via the contacts of the corresponding relays. The coil of each relay is connected to the power supply connection hole via the corresponding selection switch button in the selection switch button set.

[0008] As an optimization, the relay includes a first relay, a second relay, and a third relay, wherein,

[0009] The first end of the coil JX of the first relay is grounded, and the second end of the coil JX of the first relay is connected to the power supply terminal through the first selection switch button KX in series. The number of contacts JX1 of the first relay is the same as the number of interfaces of the PT terminal block. The first end of each contact JX1 of the first relay is connected to the interface of the PT terminal block, and the second end of each contact JX1 of the first relay is connected to the data acquisition port of the electromagnetic voltage transformer detection board.

[0010] The first end of the coil JY of the second relay is grounded, and the second end of the coil JY of the second relay is connected to the power supply terminal through the second selection switch button KY in series. The number of contacts JY1 of the second relay is the same as the number of interfaces of the PT terminal block. The first end of each second relay contact JY1 is connected to the interface of the PT terminal block, and the second end of each second relay contact JY1 is connected to the data acquisition port of the capacitor voltage transformer detection board.

[0011] The first end of the coil JZ of the third relay is grounded, and the second end of the coil JZ of the third relay is connected to the power supply terminal through a third selection switch button KZ in series. The number of contacts JZ1 of the third relay is the same as the number of interfaces of the CT terminal block. The first end of each contact JZ1 of the third relay is connected to the interface of the CT terminal block, and the second end of each contact JZ1 of the third relay is connected to the data acquisition port of the current transformer detection board.

[0012] As an optimization, the enclosure is also equipped with a voltage conversion circuit for converting the voltage of the power supply into the rated voltage suitable for the first relay, the second relay, and the third relay. The power supply wiring hole is connected to the first selection switch button KX, the second selection switch button KY, and the third selection switch button KZ respectively through the voltage conversion circuit.

[0013] As an optimization, a first light-emitting diode D1, a second light-emitting diode D2, and a third light-emitting diode D3 are respectively provided between the voltage conversion circuit and the first relay, the second relay, and the third relay. The first light-emitting diode D1 is connected in series to one end of the first selection switch button KX, the second light-emitting diode D2 is connected in series to one end of the second selection switch button KY, and the third light-emitting diode D3 is connected in series to one end of the third selection switch button KZ.

[0014] As an optimization, the first LED D1, the second LED D2, and the third LED D3 are respectively disposed at the output terminal of the voltage conversion circuit. The positive terminal of the first LED D1 is connected to the output terminal of the voltage conversion circuit, and the negative terminal of the first LED D1 is connected to the first selection switch button KX. The positive terminal of the second LED D2 is connected to the output terminal of the voltage conversion circuit, and the negative terminal of the second LED D2 is connected to the second selection switch button KY. The positive terminal of the third LED D3 is connected to the output terminal of the voltage conversion circuit, and the negative terminal of the third LED D3 is connected to the third selection switch button KZ.

[0015] As an optimization, the first light-emitting diode D1 is disposed between the coil JX of the first relay and the first selector switch button KX; the second light-emitting diode D2 is disposed between the coil JY of the second relay and the second selector switch button KY; and the third light-emitting diode D3 is disposed between the coil JZ of the third relay and the third selector switch button KZ. The positive terminal of the first light-emitting diode D1 is connected to the first selector switch button KX, and the negative terminal of the first light-emitting diode D1 is connected to the coil JX of the first relay. The positive terminal of the second light-emitting diode D2 is connected to the second selector switch button KY, and the negative terminal of the second light-emitting diode D2 is connected to the coil JY of the second relay. The positive terminal of the third light-emitting diode D3 is connected to the third selector switch button KZ, and the negative terminal of the third light-emitting diode D3 is connected to the coil KZ of the third relay.

[0016] As an optimization, the output of the voltage conversion circuit is also connected to the display screen to supply power to the display screen.

[0017] As an optimization, the first relay further includes contact JX2, the second relay further includes contact JY2, and the third relay further includes contact JZ2. The first end of contact JX2 is connected to the power supply port of the electromagnetic voltage transformer detection board, the first end of contact JY2 is connected to the power supply port of the capacitor voltage transformer detection board, and the first end of contact JY2 is connected to the power supply port of the current transformer detection board. The second ends of contact JX2, contact JY2, and contact JZ2 are all connected to the power supply wiring hole.

[0018] As an optimization, the first relay further includes contact JX3, the second relay further includes contact JY3, and the third relay further includes contact JZ3. The first end of contact JX3 is connected to the signal input / output port of the electromagnetic voltage transformer detection board, and the second end of contact JX3 is connected to the display screen. The first end of contact JY3 is connected to the signal input / output port of the capacitor voltage transformer detection board, and the second end of contact JY3 is connected to the display screen. The first end of contact JZ3 is connected to the signal input / output port of the current transformer detection board, and the second end of contact JZ3 is connected to the display screen.

[0019] As an optimization, the power connection hole is located on the panel, or the power connection hole is located on the side wall of the enclosure.

[0020] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0021] This invention integrates existing instrument transformer testing boards (including electromagnetic voltage transformer testing boards, capacitive voltage transformer testing boards, and current transformer testing boards) into a single enclosure. This allows testing personnel to test different types of instrument transformers using only one enclosure, improving the convenience of testing. Attached Figure Description

[0022] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0023] Figure 1 This is a schematic diagram of the panel structure of the detector of this utility model;

[0024] Figure 2 This is a schematic diagram of the internal structure of the detector housing of this utility model;

[0025] Figure 3 This is a schematic diagram showing another location for the LED and the selector switch;

[0026] Figure 4 This is a schematic diagram of a piano key switch.

[0027] The attached diagram shows the markings and corresponding component names:

[0028] 1-Box housing, 2-Display screen, 3-CT terminal block, 4-PT terminal block, 5-Selector switch button set, 6-Light emitting diode bulb, 7-Power switch button, 8-Power wiring hole, 9-Voltage conversion circuit. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0030] This embodiment 1 provides an integrated current transformer detector, such as... Figure 1 As shown, the device includes a housing 1, with one surface of the housing 1 serving as a panel. In this embodiment, the upper surface of the housing 1 serves as the panel.

[0031] The panel is equipped with a display screen 2 for showing test results, a CT terminal block 3 for connecting test leads to test current transformers, a PT terminal block 4 for connecting test leads to test voltage transformers, a power switch button 7 for starting the detector, and a set of selection buttons 5 for selecting the transformer test board. The enclosure 1 houses electromagnetic voltage transformer test boards, capacitive voltage transformer test boards, and current transformer test boards. The data acquisition ports of these boards are connected to the CT terminal block 3 or PT terminal block 4 via corresponding relay contacts. The power supply ports of these boards are connected to power supply terminals 8 via corresponding relay contacts and a power switch K1. In this embodiment, the power supply terminals 8 are located on the panel or on the side wall of the enclosure 1. The power supply can be AC ​​mains power or a storage battery. The power switch button 7 is connected to the power switch K1 and is used to control the power switch K1 to open or close.

[0032] In this technical solution, existing instrument transformer testing boards (including electromagnetic voltage transformer testing boards, capacitive voltage transformer testing boards, and current transformer testing boards) are installed in the same enclosure 1. The electromagnetic voltage transformer testing boards and capacitive voltage transformer testing boards share the same interface (in this embodiment, a common PT terminal block 4), while the current transformer testing boards have a separate interface (in this embodiment, a CT terminal block 3). This allows testing personnel to test different types of instrument transformers using only one enclosure 1. For more accurate testing, an isolation layer can be installed in enclosure 1 to shield external electrical signals from affecting the internal electrical signals, such as a metal isolation sleeve. Each testing board is housed within the metal isolation sleeve. The installation method of the metal isolation sleeve is existing technology; for example, refer to the technology in patent CN216485470U, and therefore will not be elaborated here.

[0033] The selection switch button set 5 has multiple selection switch buttons, such as I for connecting to the electromagnetic voltage transformer detection board, II for connecting to the capacitor voltage transformer detection board, III for connecting to the current transformer detection board, and IV for the reset button.

[0034] The selector switch set 5 also includes a reset button. The reset button, along with the first, second, and third selector switches, together form a 4-button piano key switch. A piano key switch is a convenient combination switch, typically available in sets of 4, 6, 8, 12, or 16 buttons. It operates by pressing and releasing (only one button can be pressed at a time, the other will release). There is a reset button (not a lock button), which, when pressed, will release all other buttons. The model of the piano key switch can be selected based on the actual size of the enclosure 1, such as the piano key switches from Hongmingqiang Technology. Therefore, the specific structure of the piano key switch will not be described in detail here.

[0035] like Figure 4 As shown, from left to right are the reset button, the third selection switch button, the second selection switch button, and the first selection switch button.

[0036] In this technical solution, when the current transformer test board is needed to test the current transformer, the test wires are inserted into the corresponding interfaces of the CT terminal block 3, and then the power supply is inserted into the power connection hole 8 (this step can also be done before the test wires are inserted into the CT terminal block 3). Then, the power switch button 7 and the third selection switch button are pressed in sequence. At this time, the current transformer test board is connected to the CT terminal block 3, while the electromagnetic / capacitive voltage transformer test board is disconnected from the PT terminal block 4. This ensures that the tester will not cause inaccurate testing due to incorrect terminal block insertion, or cause internal malfunction of the tester due to incorrect terminal block insertion.

[0037] It should be noted that the electromagnetic voltage transformer test board, capacitor voltage transformer test board, and current transformer test board are all existing test boards, and no modifications are made to the circuits or programs on the test boards.

[0038] The signal input and output ports of the electromagnetic voltage transformer detection board, the capacitor voltage transformer detection board, and the current transformer detection board are connected to the display screen 2 through the contacts of the corresponding relays. The coil of each relay is connected to the power wiring hole 8 through the corresponding selection switch button in the selection switch button set 5.

[0039] The signal input / output ports here include input interfaces for signal input only, output interfaces for signal output only, and input / output interfaces that can both input and output signals. Furthermore, the signals here can be control signals or other signals that need to be displayed or operated.

[0040] More specifically, the relays include a first relay, a second relay, and a third relay, such as... Figures 2-3As shown, the first end of the coil JX of the first relay is grounded, and the second end of the coil JX of the first relay is connected to the power supply terminal 8 through the first selection switch button KX in series. The number of contacts JX1 of the first relay is the same as the number of interfaces of the PT terminal block 4. The first end of each contact JX1 of the first relay is connected to the interface of the PT terminal block 4, and the second end of each contact JX1 of the first relay is connected to the data acquisition port of the electromagnetic voltage transformer detection board.

[0041] The first end of the coil JY of the second relay is grounded, and the second end of the coil JY of the second relay is connected to the power wiring hole 8 through the second selection switch button KY in series. The number of contacts JY1 of the second relay is the same as the number of interfaces of the PT terminal block 4. The first end of each second relay contact JY1 is connected to the interface of the PT terminal block 4, and the second end of each second relay contact JY1 is connected to the data acquisition port of the capacitor voltage transformer detection board.

[0042] The first end of the coil JZ of the third relay is grounded, and the second end of the coil JZ of the third relay is connected to the power supply terminal 8 through the third selector switch button KZ in series. The number of contacts JZ1 of the third relay is the same as the number of interfaces of the CT terminal block 3. The first end of each contact JZ1 of the third relay is connected to the interface of the CT terminal block 3, and the second end of each contact JZ1 of the third relay is connected to the data acquisition port of the current transformer detection board.

[0043] The first, second, and third relays are all normally open relays, meaning they only close when energized.

[0044] In this way, when one of the relays is energized (the other two relays will not be energized due to the piano key switch), the corresponding contact of this relay closes, connecting the corresponding detection board and terminal block.

[0045] In some embodiments, the first relay further includes contact JX2, the second relay further includes contact JY2, and the third relay further includes contact JZ2. The first end of contact JX2 is connected to the power supply port of the electromagnetic voltage transformer detection board, the first end of contact JY2 is connected to the power supply port of the capacitor voltage transformer detection board, the first end of contact JY2 is connected to the power supply port of the current transformer detection board, and the second ends of contact JX2, contact JY2, and contact JZ2 are all connected to the power supply wiring hole 8.

[0046] In this way, when one of the relays is energized (the other two relays will not be energized due to the key switch), the corresponding contact of this relay closes, connecting the corresponding detection board and the power connection hole 8. Thus, the power supply will only supply power to the detection board connected to the power connection hole 8, avoiding powering the detection boards that do not need to be detected, thereby achieving the effect of saving power.

[0047] In some embodiments, the first relay further includes contact JX3, the second relay further includes contact JY3, and the third relay further includes contact JZ3. The first end of contact JX3 is connected to the signal input / output port of the electromagnetic voltage transformer detection board, and the second end of contact JX3 is connected to the display screen 2. The first end of contact JY3 is connected to the signal input / output port of the capacitor voltage transformer detection board, and the second end of contact JY3 is connected to the display screen 2. The first end of contact JZ3 is connected to the signal input / output port of the current transformer detection board, and the second end of contact JZ3 is connected to the display screen 2.

[0048] Thus, when one of the relays is energized (the other two relays will not be energized due to the piano key switch), the corresponding contact of this relay closes, connecting the corresponding detection board and display screen 2. Display screen 2 then displays the detection data from the detection board connected to it. In this embodiment, display screen 2 is a touch screen, allowing data input directly onto the touch screen.

[0049] Since the first relay, the second relay, the third relay and the display screen 2 all have rated voltages, the housing 1 is also equipped with a voltage conversion circuit 9 for converting the voltage of the power supply into the rated voltage suitable for the first relay, the second relay and the third relay. The power supply terminal 8 is connected to the first selector switch button KX, the second selector switch button KY and the third selector switch button KZ respectively through the voltage conversion circuit 9.

[0050] In some embodiments, the output of the voltage conversion circuit 9 is also connected to the display screen 2 to supply power to the display screen 2.

[0051] Here, the voltage conversion circuit 9 is existing technology. For example, multiple step-down circuits or existing voltage conversion modules can be used, with each step-down circuit / voltage conversion module corresponding to a relay or display screen 2.

[0052] A first LED D1, a second LED D2, and a third LED D3 are respectively installed between the voltage conversion circuit 9 and the first, second, and third relays. The first LED D1 is connected in series with one end of the first selector switch button KX, the second LED D2 is connected in series with one end of the second selector switch button KY, and the third LED D3 is connected in series with one end of the third selector switch button KZ. If the first LED D1, the second LED D2, and the third LED D3 are installed, then an LED bulb 6 is also installed on the panel at the position corresponding to the selector switch button. In this embodiment, the LED bulb 6 is positioned next to the selector switch button. When the selector switch button is pressed, the corresponding LED will light up, thus indicating whether the selector switch button has been pressed effectively.

[0053] The LED can be positioned to the left or right of the selector switch button.

[0054] In some embodiments, a first light-emitting diode D1, a second light-emitting diode D2, and a third light-emitting diode D3 are respectively disposed at the output terminal of the voltage conversion circuit 9. The positive terminal of the first light-emitting diode D1 is connected to the output terminal of the voltage conversion circuit 9, and the negative terminal of the first light-emitting diode D1 is connected to the first selection switch button KX. The positive terminal of the second light-emitting diode D2 is connected to the output terminal of the voltage conversion circuit 9, and the negative terminal of the second light-emitting diode D2 is connected to the second selection switch button KY. The positive terminal of the third light-emitting diode D3 is connected to the output terminal of the voltage conversion circuit 9, and the negative terminal of the third light-emitting diode D3 is connected to the third selection switch button KZ.

[0055] In some embodiments, a first light-emitting diode D1 is disposed between the coil JX of the first relay and the first selector switch button KX; a second light-emitting diode D2 is disposed between the coil JY of the second relay and the second selector switch button KY; and a third light-emitting diode D3 is disposed between the coil JZ of the third relay and the third selector switch button KZ. The positive terminal of the first light-emitting diode D1 is connected to the first selector switch button KX, and the negative terminal of the first light-emitting diode D1 is connected to the coil JX of the first relay. The positive terminal of the second light-emitting diode D2 is connected to the second selector switch button KY, and the negative terminal of the second light-emitting diode D2 is connected to the coil JY of the second relay. The positive terminal of the third light-emitting diode D3 is connected to the third selector switch button KZ, and the negative terminal of the third light-emitting diode D3 is connected to the coil KZ of the third relay.

[0056] To prevent dust and water damage, a cover that matches the enclosure 1 can be installed. The cover can cover the enclosure 1, thereby protecting the panel and the circuit board inside the enclosure 1.

[0057] The above specific embodiments further illustrate the purpose, technical solution and beneficial effects of this utility model. It should be understood that the above are only specific embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. An integrated current transformer tester, characterized in that, The device includes a housing, one surface of which serves as a panel. The panel includes a display screen for showing test results, a CT terminal block for connecting test leads to test current transformers, a PT terminal block for connecting test leads to test voltage transformers, a power switch button for starting the test instrument, and a set of selection switches for selecting the transformer test board. The housing houses an electromagnetic voltage transformer test board, a capacitive voltage transformer test board, and a current transformer test board. The data acquisition ports of these three test boards are connected via corresponding... The contacts of the relays are connected to the CT terminal block or PT terminal block, and the power supply ports of the electromagnetic voltage transformer detection board, the capacitor voltage transformer detection board, and the current transformer detection board are respectively connected to the power supply connection hole for connecting to the power supply through the corresponding relay contacts and the power switch. The signal input and output ports of the electromagnetic voltage transformer detection board, the capacitor voltage transformer detection board, and the current transformer detection board are respectively connected to the display screen through the corresponding relay contacts. The coil of each relay is respectively connected to the power supply connection hole through the corresponding selection switch button in the selection switch button set.

2. The integrated current transformer tester according to claim 1, characterized in that, The relay includes a first relay, a second relay, and a third relay, wherein, The first end of the coil JX of the first relay is grounded, and the second end of the coil JX of the first relay is connected to the power supply terminal through the first selection switch button KX in series. The number of contacts JX1 of the first relay is the same as the number of interfaces of the PT terminal block. The first end of each contact JX1 of the first relay is connected to the interface of the PT terminal block, and the second end of each contact JX1 of the first relay is connected to the data acquisition port of the electromagnetic voltage transformer detection board. The first end of the coil JY of the second relay is grounded, and the second end of the coil JY of the second relay is connected to the power supply terminal through the second selection switch button KY in series. The number of contacts JY1 of the second relay is the same as the number of interfaces of the PT terminal block. The first end of each second relay contact JY1 is connected to the interface of the PT terminal block, and the second end of each second relay contact JY1 is connected to the data acquisition port of the capacitor voltage transformer detection board. The first end of the coil JZ of the third relay is grounded, and the second end of the coil JZ of the third relay is connected to the power supply terminal through a third selection switch button KZ in series. The number of contacts JZ1 of the third relay is the same as the number of interfaces of the CT terminal block. The first end of each contact JZ1 of the third relay is connected to the interface of the CT terminal block, and the second end of each contact JZ1 of the third relay is connected to the data acquisition port of the current transformer detection board.

3. The integrated current transformer detector according to claim 2, characterized in that, The enclosure is also equipped with a voltage conversion circuit for converting the voltage of the power supply into the rated voltage suitable for the first relay, the second relay, and the third relay. The power supply wiring hole is connected to the first selection switch button KX, the second selection switch button KY, and the third selection switch button KZ respectively through the voltage conversion circuit.

4. The integrated current transformer tester according to claim 3, characterized in that, A first light-emitting diode (LED) D1, a second light-emitting diode (LED) D2, and a third light-emitting diode (LED) D3 are respectively provided between the voltage conversion circuit and the first relay, the second relay, and the third relay. The first LED D1 is connected in series with one end of the first selection switch button KX, the second LED D2 is connected in series with one end of the second selection switch button KY, and the third LED D3 is connected in series with one end of the third selection switch button KZ.

5. The integrated current transformer tester according to claim 4, characterized in that, The first light-emitting diode D1, the second light-emitting diode D2, and the third light-emitting diode D3 are respectively disposed at the output terminal of the voltage conversion circuit. The positive terminal of the first light-emitting diode D1 is connected to the output terminal of the voltage conversion circuit, and the negative terminal of the first light-emitting diode D1 is connected to the first selection switch button KX. The positive terminal of the second light-emitting diode D2 is connected to the output terminal of the voltage conversion circuit, and the negative terminal of the second light-emitting diode D2 is connected to the second selection switch button KY. The positive terminal of the third light-emitting diode D3 is connected to the output terminal of the voltage conversion circuit, and the negative terminal of the third light-emitting diode D3 is connected to the third selection switch button KZ.

6. The integrated current transformer tester according to claim 4, characterized in that, The first light-emitting diode D1 is disposed between the coil JX of the first relay and the first selector switch button KX; the second light-emitting diode D2 is disposed between the coil JY of the second relay and the second selector switch button KY; and the third light-emitting diode D3 is disposed between the coil JZ of the third relay and the third selector switch button KZ. The positive terminal of the first light-emitting diode D1 is connected to the first selector switch button KX, and the negative terminal of the first light-emitting diode D1 is connected to the coil JX of the first relay. The positive terminal of the second light-emitting diode D2 is connected to the second selector switch button KY, and the negative terminal of the second light-emitting diode D2 is connected to the coil JY of the second relay. The positive terminal of the third light-emitting diode D3 is connected to the third selector switch button KZ, and the negative terminal of the third light-emitting diode D3 is connected to the coil KZ of the third relay.

7. The integrated current transformer tester according to claim 3, characterized in that, The output of the voltage conversion circuit is also connected to the display screen to supply power to the display screen.

8. The integrated current transformer tester according to claim 2, characterized in that, The first relay further includes contact JX2, the second relay further includes contact JY2, and the third relay further includes contact JZ2. The first end of contact JX2 is connected to the power supply port of the electromagnetic voltage transformer detection board, the first end of contact JY2 is connected to the power supply port of the capacitor voltage transformer detection board, and the first end of contact JY2 is connected to the power supply port of the current transformer detection board. The second ends of contact JX2, contact JY2, and contact JZ2 are all connected to the power supply wiring hole.

9. The integrated current transformer tester according to claim 2, characterized in that, The first relay further includes contact JX3, the second relay further includes contact JY3, and the third relay further includes contact JZ3. The first end of contact JX3 is connected to the signal input / output port of the electromagnetic voltage transformer detection board, and the second end of contact JX3 is connected to the display screen. The first end of contact JY3 is connected to the signal input / output port of the capacitor voltage transformer detection board, and the second end of contact JY3 is connected to the display screen. The first end of contact JZ3 is connected to the signal input / output port of the current transformer detection board, and the second end of contact JZ3 is connected to the display screen.

10. The integrated current transformer tester according to claim 2, characterized in that, The power connection hole is located on the panel or on the side wall of the enclosure.

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