Automatic switching device and method for electrical tests of bushings

Abstract

The present application belongs to the field of extra-high voltage bushing electrical test, and particularly relates to a bushing electrical test automatic conversion device and method, which comprises a remote computer operating system, a conversion control box main body, a conversion control box front panel and a conversion control box rear panel. The front part of the conversion control box main body is provided with the conversion control box front panel. The present application realizes real-time visual monitoring of test state, channel selection and grounding condition through remote operation of a computer interface isolated by an optical fiber, utilization of an integrated system touch screen, multiplexing buttons and multi-color state indicator lights, red dielectric loss output indication, orange partial discharge output indication and green grounding indication. An operator can quickly judge the system operation state through intuitive light signals. The dielectric loss setting button and the partial discharge setting button adopt multiplexing logic design, and channel enabling, switching and grounding control can be completed through simple clicking. In combination with the parameter setting and state monitoring functions of the touch screen, the operation complexity is greatly reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of extra-high voltage bushing electrical test, in particular to a bushing electrical test automatic switching device and method. BACKGROUND

[0002] As a core component of modern power industry, the safe and stable operation of the extra-high voltage power transmission system is directly related to the reliability and economy of national energy transmission. As a key device in the system, the extra-high voltage bushing mainly undertakes the important function of connecting the converter valve hall in the converter station with the external transmission line, and is used to lead the high and low voltage windings of the transformer out of the oil tank, with the dual functions of insulation and fixation. In high-voltage direct-current transmission projects, the technical content and performance requirements of the extra-high voltage bushing are extremely high, and its quality directly determines the stability and safety of the entire power transmission system, and is one of the core components to ensure uninterrupted operation of power transmission.

[0003] From the type, the extra-high voltage bushing mainly includes four types:

[0004] The extra-high voltage oil-paper bushing adopts an oil-paper composite insulation structure, has high insulation strength and good heat dissipation performance;

[0005] The extra-high voltage impregnated paper bushing strengthens the insulation performance of paper through impregnation process, and has excellent moisture and dirt resistance;

[0006] The extra-high voltage SF6 gas insulated bushing realizes compact design by using the high insulation characteristics of SF6 gas, while reducing the impact on the environment;

[0007] The extra-high voltage impregnated fiber bushing impregnates insulation glue with fiber material, and has high strength and good insulation performance.

[0008] Different types of bushings need to pass strict electrical test to verify their insulation reliability, voltage resistance performance and operation stability, which is a key link to ensure their factory quality and engineering applicability.

[0009] From the industry level, the power equipment accounts for about 70% of the converter station investment, among which the converter transformer and the converter valve account for 46%. Although the DC wall bushing accounts for only 1.4% as a key component, it has great technical difficulty. The development and test of the extra-high voltage bushing have become an important topic for the self-development of China's power equipment, and the bushing production and manufacturing units in the middle stream industry chain urgently need reliable test equipment to conduct comprehensive test research and factory inspection on high voltage bushings and other high voltage test products of various voltage grades to meet the strict requirements of extra-high voltage engineering on equipment performance;

[0010] However, in the conventional high-voltage sleeve test process, different test items, such as partial discharge measurement, dielectric loss measurement, power frequency withstand voltage test, lightning impulse test, etc., need to manually switch the connection and adjust the test circuit repeatedly, which is not only cumbersome and inefficient, but also has high-voltage safety risks caused by human error; At the same time, the technical difficulties such as multi-channel synchronous test demand, test state interlocking control, anti-interference ability also put forward higher requirements for the automation and intelligent level of the test equipment.

[0011] Therefore, the present application provides a sleeve electrical test automatic conversion device and method. SUMMARY

[0012] In order to make up for the deficiencies of the prior art and solve at least one technical problem raised in the background art.

[0013] The technical scheme adopted by the present application to solve its technical problems is: the sleeve electrical test automatic conversion device comprises a remote computer operating system, a conversion control box main body, a conversion control box front panel and a conversion control box rear panel, the front part of the conversion control box main body is provided with the conversion control box front panel, the rear part of the conversion control box main body is provided with the conversion control box rear panel, and the inside of the conversion control box main body is provided with a PLC;

[0014] The conversion control box front panel comprises a power switch PWR, a power frequency impulse button, a dielectric loss partial discharge button, a system touch screen, a CX-OUT interface, a dielectric loss output indicator lamp, a dielectric loss setting button, a partial discharge setting button, a partial discharge output indicator lamp, a PD output interface, a first channel grounding indication, a PD output grounding indication and a second channel grounding indication;

[0015] The conversion control box rear panel comprises a first input terminal, a second input terminal, a GROUND grounding terminal, a too network communication port, a STOPIN terminal, a cooling fan, a temperature controller, an ST expansion optical port, a power socket and a power fuse.

[0016] Preferably, the power switch PWR is used for power on / off of the conversion control box system;

[0017] The power frequency impulse button is a power frequency impulse selection button, after switching, the system will automatically ground all channels;

[0018] The dielectric loss partial discharge button is a dielectric loss partial discharge selection button, which needs to be selected and placed in the ON state before using the conversion box function.

[0019] Preferably, the system touch screen is used for parameter setting of the conversion box input / output channel, system state monitoring and system man-machine interaction; the FAULT is a channel fault warning lamp, and the COMM is a communication normal operation indicator lamp;

[0020] The CX-OUT interface is a dielectric loss CX output channel of the conversion box. CH1, CH2, CH3, CH4, CH5, CH6, CH7 and CH8 are output from the channel through internal switching. During measurement, the channel must not be open or virtually connected;

[0021] The dielectric loss output indicator is used to indicate the dielectric loss output state of each corresponding channel. The indicator is red.

[0022] Preferably, the dielectric loss setting button is a click button that can select the dielectric loss output channel of the corresponding unit. The button is a multiplex button. The first click enables the first channel. The second click disables the first channel and enables the second channel. The third click disables all the selected channels and connects them to the ground.

[0023] The partial discharge setting button is a click button that can select the partial discharge output channel of the corresponding unit. The button is a multiplex button. The first click enables the partial discharge test output of the balance method. The second click disables the balance method and enables the partial discharge test output of the first channel of the series method. The third click disables the balance method and enables the partial discharge test output of the second channel of the series method. The fourth click disables all the selected channels and connects them to the ground.

[0024] Preferably, the partial discharge output indicator is used to indicate the partial discharge output state of each corresponding channel. The indicator is orange.

[0025] The PD output interface is a partial discharge output channel of the conversion box. CH1-CH2, CH3-CH4, CH5-CH6 and CH7-CH8 are output from the channel through internal switching.

[0026] The first channel ground indication is used to indicate the grounding condition of the first channel. The indication is displayed by a green indicator.

[0027] The PD output ground indication is used to indicate the connection condition of the partial discharge test and the loop ground. The indication is displayed by a green indicator.

[0028] The second channel ground indication is used to indicate the grounding condition of the second channel. The indication is displayed by a green indicator.

[0029] Preferably, the first input terminal includes CH2, CH4, CH6 and CH8 channel input terminals. High-voltage bushings CH2, CH4, CH6 and CH8 are connected to the terminals. The terminals are marked in yellow and can be fastened by 6mm banana plugs or thread nose screws.

[0030] The second input terminal includes CH1, CH3, CH5 and CH7 channel input terminals. High-voltage bushings CH1, CH3, CH5 and CH7 are connected to the terminals. The terminals are marked in red and can be fastened by 6mm banana plugs or thread nose screws.

[0031] The GROUND grounding terminal is preferably a conversion box grounding terminal, which is kept at the same grounding point as the tested product;

[0032] The Ethernet communication port is used for remote access and later expansion;

[0033] The STOPIN terminal is a function expansion terminal, and users can access the signal to link with other control devices;

[0034] The cooling fan is used for cooling the power supply and control system power supply of the isolation unit module;

[0035] The temperature controller is an automatic temperature monitoring device in the case, and users can set the starting or stopping temperature range according to the situation;

[0036] The ST expansion optical port is used for system remote expansion, and is adapted to a fiber wavelength of multimode 1310 nm, a fiber core diameter of 62.5 μm, and a transmission distance of 2 kM, and is used for optical fiber communication computer remote monitoring.

[0037] A method for automatically converting a bushing electrical test device, the method comprising the following steps:

[0038] S1, turn on the power switch PWR of the conversion control box main body to power on the system, and perform parameter pre-setting of the input and output channels and initial monitoring of the system state through the system touch screen or remote computer on the front panel of the conversion control box, to ensure that the COMM communication normal operation indicator light is on;

[0039] S2, select the placement position according to the test type: the DC partial discharge test is placed on the DC generator coupling capacitor side, the AC partial discharge test is placed on the power frequency capacitor voltage divider side, the dielectric loss test is placed on the power frequency tested product side, and the lightning impulse discharge test is placed on the lightning impulse device test product side;

[0040] S3, ground the conversion box through the GROUND grounding terminal on the rear panel of the conversion control box, and keep the same grounding point as the tested product;

[0041] S4, signal access: the coupling capacitor output signal of the DC partial discharge test, the coupling voltage divider output signal of the AC partial discharge test, and the measured capacitor output signal of the dielectric loss test are correspondingly accessed to the CH1-CH8 channels, wherein the CH2, CH4, CH6, and CH8 channels are accessed to the first input terminal with yellow identification, the CH1, CH3, CH5, and CH7 channels are accessed to the second input terminal with red identification, and a 6mm banana plug or a thread nose screw is used for fastening; the lightning impulse discharge test connects the rear side input channels of each bushing to the impulse tested product through the first input terminal and the second input terminal, and shorts the test product to the ground;

[0042] S5, mode and channel setting: DC partial discharge test and AC partial discharge test operation dielectric loss partial discharge button is placed in ON state, click partial discharge setting button to select partial discharge output channel, enable the first channel of balanced method partial discharge test output for the first time, disable the balanced method and enable the first channel of series method partial discharge test for the second time, disable the balanced method and enable the second channel of series method partial discharge test for the third time;

[0043] Dielectric loss test test operation dielectric loss partial discharge button is placed in ON state, click dielectric loss setting button to select dielectric loss output channel, enable the first channel for the first time, cut off the first channel and enable the second channel for the second time;

[0044] Lightning impulse discharge test operation power frequency impulse button is switched to power frequency impulse mode, and the system automatically grounds all channels;

[0045] S6, state confirmation: DC partial discharge test and AC partial discharge test observe the orange state of the orange partial discharge output indicator light to confirm that the partial discharge output is normal, and observe the green indicator light of the first channel grounding indication, the second channel grounding indication and the PD output grounding indication to confirm that the non-selected channel grounding is normal;

[0046] Dielectric loss test test observes the red state of the red dielectric loss output indicator light to confirm that the dielectric loss output is normal;

[0047] Lightning impulse discharge test observes the green indicator light of the first channel grounding indication and the second channel grounding indication to confirm that all channels are grounded normally;

[0048] S7, execute test and signal transmission: DC partial discharge test and AC partial discharge test transmit the partial discharge output signal to the partial discharge instrument through the PD output interface for measurement;

[0049] Dielectric loss test transmits the dielectric loss output signal to the dielectric loss instrument through the CX-OUT interface, adopts positive connection, external standard capacitor, external high voltage test mode to press and test, and ensures that the CX-OUT interface is not open or virtual;

[0050] Lightning impulse discharge test executes lightning impulse test, checks the withstand voltage of the test sample, and observes the FAULT channel fault warning light and the COMM communication normal operation indicator light of the system touch screen after the test is completed.

[0051] The beneficial effects of the application are as follows:

[0052] 1. The automatic conversion device and method for electrical test of bushings, which realizes real-time visual monitoring of test state, channel selection and grounding condition by remote operation through optical fiber isolation computer interface, utilizes integrated system touch screen, multiplexed buttons and multi-color status indicator, red dielectric loss output indication, orange partial discharge output indication and green grounding indication, and enables operation personnel to quickly judge system operation state through intuitive light signals;

[0053] The dielectric loss setting button and the partial discharge setting button adopt multiplexed logic design, and channel enabling, switching and grounding control can be completed by simple clicking, which, in combination with parameter setting and state monitoring functions of the touch screen, greatly reduces operation complexity and improves human-machine interaction friendliness.

[0054] 2. The automatic conversion device and method for electrical test of bushings, which takes PLC as a logic control core to realize automatic conversion of each measurement channel, supports multi-channel synchronous measurement, for example, balance method partial discharge test can simultaneously test AC and DC partial discharge of eight bushings through one 4-channel digital partial discharge comprehensive analyzer, and dielectric loss test can simultaneously test dielectric loss of eight bushings through one dielectric loss measuring instrument in steps, without repeated manual wiring switching during the test process, effectively shortening the test cycle.

[0055] The system has operation control interlocking function, and different test states are independent of each other, such as power frequency impulse, partial discharge measurement and dielectric loss measurement, and when switching, automatic safety operation such as grounding of non-selected channel is completed, avoiding test interruption or equipment risk caused by human error;

[0056] The system is equipped with self-diagnosis and self-protection functions, and if an abnormality occurs during the test process, such as channel failure or communication interruption, the FAULT warning light will light up in time and prompt the fault cause through the system interface, facilitating quick troubleshooting and reducing downtime.

[0057] 3. The automatic conversion device and method for electrical test of bushings, which adopts a two-stage isolation system of relays and photoelectric isolation, in combination with a built-in SPD module and an EMC filter, to effectively suppress surge, electromagnetic interference and ground potential rise interference, ensure the stability of the measurement and control system in a high-voltage environment, and reduce the risk of equipment damage. The grounding specification is strictly implemented, the GROUND grounding terminal and the tested product ground are kept at the same grounding point, the PD output grounding indication monitors the loop ground connection state in real time, ensures reliable grounding during the test process, and avoids high-voltage counterattack danger;

[0058] The high-voltage and low-voltage circuits are physically isolated, and the dielectric loss output channel (CX-OUT) is designed to be strictly prohibited from being open or virtually connected, and the state monitoring is combined with the test state interlocking mechanism to double-protect the safety of operation personnel and equipment from both software and hardware levels.

[0059] 4. The automatic switching device and method for electrical test of bushing according to the present application, which integrates functions such as power frequency withstand voltage, lightning impulse, partial discharge measurement (balance method / series method), dielectric loss and capacitance measurement, can meet the needs of parallel test of multiple high-voltage bushings or high-voltage test samples one by one or synchronously, and does not need to additionally configure multiple sets of special equipment, thereby saving equipment investment and space;

[0060] Supports multiple test types such as DC partial discharge, AC partial discharge, dielectric loss test, lightning impulse discharge, and the like, and can adapt to different test scenes through simple mode switching (power frequency impulse button, dielectric loss and partial discharge button), and flexibly meets the diversified test needs of a high-voltage test hall;

[0061] The input terminal adopts a 6mm banana plug or a wire nose screw fastening design, is compatible with different wiring modes, and distinguishes the channel groups through yellow / red identification, thereby improving wiring convenience and accuracy.

[0062] 5. The automatic switching device and method for electrical test of bushing according to the present application, which adopts a 19-inch standard case design, each channel has a shielding anti-interference function, and combines a remote isolation control mode of optical fiber communication, thereby effectively reducing the influence of space charge, power supply voltage and the like on test signals, and ensuring the accuracy of key test data such as partial discharge and dielectric loss, for example, the fluctuation of AC partial discharge test is only 1-2pC, thereby meeting the needs of high-precision test;

[0063] The switching logic of "first grounding-gear switching-then separation" is adopted during dielectric loss measurement, which avoids signal disturbance during the switching process under high voltage, and ensures the consistency of test data after channel switching under different voltages.

[0064] 6. The automatic switching device and method for electrical test of bushing according to the present application, which is equipped with a too net communication port, an ST expansion optical port and a STOPIN function expansion terminal, supports remote access, system expansion and linkage with other control equipment, and provides convenience for later upgrading of multi-machine networking or access to a DCS system;

[0065] Supports two modes of local operation (button / touch screen) and remote control (computer optical fiber / ethernet wire connection), and an operator can complete test control outside a safe distance, which is especially suitable for safety operation specifications of a high-voltage test hall, and is convenient for remote storage and analysis of test data.

[0066] 7. The automatic switching device and method for electrical test of bushing according to the present application, which has a modular design, clear structure, and a cooling fan and a temperature controller cooperate to realize automatic monitoring of the temperature in the case, thereby ensuring stable operation of the equipment under an environmental temperature of-5℃ to 55℃, and reducing maintenance cost;

[0067] The software and hardware multiple redundancy design reduces the risk of core device damage, the remote communication and data interaction adopts the self-owned patent topology architecture, the use amount of multi-core control cable is reduced, the field wiring and later maintenance are facilitated, and the overall service life and reliability of the equipment are improved. BRIEF DESCRIPTION OF DRAWINGS

[0068] The application will be further described below in combination with the drawings.

[0069] Figure 1 is the front view of the conversion box in the application;

[0070] Figure 2 is the rear view of the conversion box in the application;

[0071] Figure 3 is the DC partial discharge test circuit diagram in the application;

[0072] Figure 4 is the AC partial discharge test circuit diagram in the application;

[0073] Figure 5 is the dielectric loss test test circuit diagram in the application;

[0074] Figure 6 is the lightning impulse discharge test circuit diagram in the application;

[0075] Figure 7 is the main circuit electrical principle diagram in the application.

[0076] In the figure: 1, conversion control box main body; 2, conversion control box front panel; 21, power switch PWR; 22, power frequency impulse button; 23, dielectric loss partial discharge button; 24, system touch screen; 25, CX-OUT interface; 26, dielectric loss output indicator light; 27, dielectric loss setting button; 28, partial discharge setting button; 29, partial discharge output indicator light; 210, PD output interface; 211, first channel grounding indication; 212, PD output grounding indication; 213, second channel grounding indication; 3, conversion control box rear panel; 31, first input terminal; 32, second input terminal; 33, GROUND grounding terminal; 34, Ethernet communication port; 35, STOPIN terminal; 36, cooling fan; 37, temperature controller; 38, ST expansion optical port; 39, power socket; 310, power supply fuse. DETAILED DESCRIPTION

[0077] In order to make the technical means, creative features, purposes and effects realized by the application easy to understand, the application will be further described below in combination with specific embodiments.

[0078] As Figures 1 to 7As shown, the sleeve electrical test automatic conversion device of the embodiment of the application comprises a remote computer operating system, a conversion control box main body 1, a conversion control box front panel 2 and a conversion control box rear panel 3. The front part of the conversion control box main body 1 is provided with the conversion control box front panel 2, and the rear part of the conversion control box main body 1 is provided with the conversion control box rear panel 3. The inside of the conversion control box main body 1 is provided with a PLC.

[0079] The conversion control box front panel 2 comprises a power switch PWR21, a power frequency impact button 22, a dielectric loss local discharge button 23, a system touch screen 24, a CX-OUT interface 25, a dielectric loss output indicator lamp 26, a dielectric loss setting button 27, a local discharge setting button 28, a local discharge output indicator lamp 29, a PD output interface 210, a first channel grounding indicator 211, a PD output grounding indicator 212 and a second channel grounding indicator 213.

[0080] The conversion control box rear panel 3 comprises a first input terminal 31, a second input terminal 32, a GROUND grounding terminal 33, a too net communication port 34, a STOPIN terminal 35, a cooling fan 36, a temperature controller 37, an ST expansion optical port 38, a power socket 39 and a power supply fuse 310.

[0081] The power switch PWR21 is used for switching on and off the power supply of the conversion control box system.

[0082] The power frequency impact button 22 is a power frequency impact selection button. After switching, the system will automatically ground all channels.

[0083] The dielectric loss local discharge button 23 is a dielectric loss local discharge selection button. Before using the conversion box function, the button needs to be selected and placed in the ON state.

[0084] The system touch screen 24 is used for parameter setting of the conversion box input and output channels, system state monitoring and system man-machine interaction. The FAULT is a channel fault warning lamp, and the COMM is a communication normal operation indicator lamp.

[0085] The CX-OUT interface 25 is a conversion box dielectric loss CX output channel. CH1, CH2, CH3, CH4, CH5, CH6, CH7 and CH8 are all output from the channel through internal switching. When measuring, the channel is strictly prohibited to be open or virtually connected.

[0086] The dielectric loss output indicator lamp 26 is used for indicating the dielectric loss output state of each corresponding channel. The lamp is red.

[0087] The dielectric loss setting button 27 is a button that can select the dielectric loss output channel of the corresponding unit. The button is a multiplexing button. The first click enables the first channel, the second click removes the first channel and enables the second channel, and the third click removes all the selected channels and grounds them.

[0088] The partial discharge setting button 28 can be clicked to select the partial discharge output channel of the corresponding unit. This button is a multiplexed button. Clicking it once enables the balanced method partial discharge test output, clicking it twice disables the balanced method and enables the first channel series method partial discharge test output, clicking it three times disables the balanced method and enables the second channel series method partial discharge test output, and clicking it four times cuts off all the selected channels and grounds them.

[0089] Partial discharge output indicator 29 is used to indicate the partial discharge output status of each corresponding channel; this light is orange.

[0090] PD output interface 210 is the partial discharge output channel of the converter box. CH1-CH2, CH3-CH4, CH5-CH6, and CH7-CH8 are two channels that are switched internally and output from this channel respectively.

[0091] The first channel grounding indicator 211 is used to indicate the grounding status of the first channel, and is displayed by a green indicator light;

[0092] The PD output ground indicator 212 is used to indicate the connection status of partial discharge test and loop ground, which is displayed by a green indicator light;

[0093] The second channel grounding indicator 213 is used to indicate the grounding status of the second channel, and is displayed as a green indicator light.

[0094] The first input terminal 31 includes CH2, CH4, CH6 and CH8 channel input terminals, and external high voltage bushings CH2, CH4, CH6 and CH8 channels are marked in yellow. They can be fastened with 6mm banana plugs or wire lug screws.

[0095] The second input terminal 32 includes CH1, CH3, CH5 and CH7 channel input terminals, and external high voltage bushings CH1, CH3, CH5 and CH7 channels are marked in red. They can be fastened with 6mm banana plugs or wire lug screws.

[0096] Grounding terminal 33 is the grounding terminal of the conversion box, and it maintains the same grounding point as the ground of the tested object;

[0097] Ethernet port 34 is used for remote access and future expansion;

[0098] STOPIN terminal 35 is a function expansion terminal, which allows users to connect this signal for linkage with other control devices;

[0099] Cooling fan 36 is used for cooling the power supply of the isolation unit module and the power supply of the control system;

[0100] Temperature controller 37 is an automatic temperature monitoring device inside the chassis. Users can set the start or stop temperature range as needed.

[0101] The ST expansion optical port 38 is used for system remote expansion, and is adapted to fiber wavelength of multimode 1310nm, fiber core diameter of 62.5μm, and transmission distance of 2kM, and is used for fiber communication computer remote monitoring.

[0102] A method for automatically switching a sleeve electrical test device, comprising the following steps:

[0103] S1, turn on the power switch PWR21 of the switching control box main body 1 to power on the system, and perform parameter pre-setting of the input and output channels and initial monitoring of the system state through the system touch screen 24 of the front panel 2 of the switching control box or a remote computer, and ensure that the COMM communication normal operation indicator light is on;

[0104] S2, select the placement position according to the test type: the DC partial discharge test is placed on the side of the coupling capacitor of the DC generator, the AC partial discharge test is placed on the side of the power frequency capacitor voltage divider, the dielectric loss test is placed on the side of the tested product, and the lightning impulse discharge test is placed on the side of the lightning impulse device product;

[0105] S3, ground the switching box through the GROUND grounding terminal 33 of the rear panel 3 of the switching control box, and keep the same grounding point with the tested product;

[0106] S4, signal access: the coupling capacitor output signal of the DC partial discharge test, the coupling voltage divider output signal of the AC partial discharge test, and the measured capacitor output signal of the dielectric loss test are accessed to the CH1-CH8 channels, wherein the CH2, CH4, CH6, and CH8 channels are accessed to the first input terminal 31 of the yellow mark, the CH1, CH3, CH5, and CH7 channels are accessed to the second input terminal 32 of the red mark, and a 6mm banana plug or a thread nose screw is used for fastening; the lightning impulse discharge test connects the rear side each sleeve input channel to the impulse tested product through the first input terminal 31 and the second input terminal 32, and shorts the product to the ground;

[0107] S5, mode and channel setting: the dielectric loss partial discharge button 23 is operated to be in the ON state for the DC partial discharge test and the AC partial discharge test, the partial discharge setting button 28 is clicked to select the partial discharge output channel, the first time enables the balance method partial discharge test output, the second time disables the balance method and enables the first channel series method partial discharge test, and the third time disables the balance method and enables the second channel series method partial discharge test;

[0108] The dielectric loss partial discharge button 23 is operated to be in the ON state for the dielectric loss test, the dielectric loss setting button 27 is clicked to select the dielectric loss output channel, the first time enables the first channel, and the second time cuts off the first channel and enables the second channel;

[0109] The power frequency impulse button 22 is operated to switch to the power frequency impulse mode for the lightning impulse discharge test, and the system automatically grounds all the channels.

[0110] S6, state confirmation: direct current partial discharge test and alternating current partial discharge test observe the orange light of partial discharge output indicator 29 to confirm that the partial discharge output is normal, and observe the green indicator lights of first channel grounding indicator 211, second channel grounding indicator 213 and PD output grounding indicator 212 to confirm that the non-selected channel grounding is normal;

[0111] Dielectric loss test test observes the red light of dielectric loss output indicator 26 to confirm that the dielectric loss output is normal;

[0112] Lightning impulse discharge test observes the green indicator lights of first channel grounding indicator 211 and second channel grounding indicator 213 to confirm that all channel grounding is normal;

[0113] S7, execute test and signal transmission: direct current partial discharge test and alternating current partial discharge test transmit partial discharge output signal to partial discharge instrument through PD output interface 210 for measurement;

[0114] Dielectric loss test test transmits dielectric loss output signal to dielectric loss instrument through CX-OUT interface 25, adopts positive connection, external standard capacitor, external high voltage test mode to press and test, and ensures that CX-OUT interface 25 has no open circuit or virtual connection;

[0115] Lightning impulse discharge test executes lightning impulse test, checks the impact voltage resistance of the test product, and observes the FAULT channel fault warning light and COMM communication normal operation indicator light of system touch screen 24 after the test is completed.

[0116] Specifically,

[0117] System composition and requirements:

[0118] The device is mainly composed of a conversion box and a remote computer operating system, and the automatic conversion device can realize local or remote operation of each measurement channel to perform grounding, impulse or power frequency test, partial discharge measurement (multi-channel synchronous measurement) and dielectric loss measurement conversion. The system has operation control interlocking and real-time state indication. It is mainly used in high voltage test hall to meet the automatic conversion of test conditions such as grounding, partial discharge measurement, dielectric capacity measurement, power frequency voltage withstand test and lightning impulse test of multiple high voltage bushings or high voltage test products in parallel.

[0119] The technical requirements of each component part are as follows:

[0120] I. Conversion box:

[0121] The converter box can be placed next to the test tank. Multiple bushing tap connection cables are connected to the converter box according to their numbers. One end of the connection cable uses an alligator clip to connect to the tap, and the other end uses a banana plug for a reliable connection to the converter box. The converter box has multiple functions including power frequency withstand voltage testing, lightning impulse withstand voltage testing, partial discharge measurement, and dielectric loss capacitance measurement.

[0122] The various test states are independent of each other. When one state is used, the other states are open circuits. For example, when performing power frequency withstand voltage tests and lightning impulse withstand voltage tests, all bushing taps are grounded, and the partial discharge measurement and dielectric loss capacitance measurement terminals are open circuits; when performing partial discharge measurements, the grounding and dielectric loss capacitance measurements are open circuits.

[0123] The partial discharge measurement has 8 input interfaces and 4 output interfaces. The impedance box is placed inside the conversion box. The partial discharge quantity can be measured using the balance method and the series method.

[0124] The dielectric loss capacitance measurement and partial discharge measurement share 8 input interfaces and 1 output interface (i.e., the Cx interface is connected to the high-voltage bridge Cx). When measuring the first bushing, all other interfaces are grounded; when measuring the second bushing, all other interfaces are grounded, and so on. When performing dielectric loss capacitance measurement under high voltage, the switching cabinet has the function of first grounding, then switching the range, and then disconnecting the grounding again when switching to the next measurement point.

[0125] The conversion box is connected to the indoor control system via fiber optic cable, and the conversion cabinet contains a PLC module. The conversion box outputs four BNC interfaces and one CX output interface, which are connected to the high-voltage bridge of the partial discharge instrument via user cables.

[0126] II. Control System:

[0127] The system uses an industrial control computer for switching and control operations. The industrial computer is an Advantech brand, and the monitor is a 24-inch LED high-brightness display. The operating system is Windows. In remote operation mode, if any components in the chassis are damaged, the system will activate ground short-circuit protection and issue a warning to prompt for repair.

[0128] Device operating conditions:

[0129] Location of use: Indoors;

[0130] Ambient temperature: -5℃ to 55℃;

[0131] Ambient humidity: Monthly average maximum relative humidity ≤ 85% (25℃);

[0132] Altitude: ≤1000m.

[0133] III. Main circuit electrical schematic diagram as follows Figure 7 As shown;

[0134] Description:

[0135] This scheme is a high-voltage capacitor bushing for example, according to the user's actual test habits and needs to use the balance method or direct series method for partial discharge test; dielectric loss measurement with the positive connection, external standard capacitor, high voltage test for example design; this scheme uses the balance method test can be through the 4 channel partial discharge instrument at the same time for 8 bushing partial discharge test, using the direct series method test can be through the 4 channel partial discharge instrument at the same time for 4 bushing separate partial discharge test; this scheme can be through the PLC control relay group one by one to complete the dielectric loss test of 8 bushings.

[0136] Note: must ensure that each external cable connection is reliable and no damage, otherwise there may be high voltage counterattack risk.

[0137] Four, conversion box setting and operation

[0138] Conversion box operation preparation:

[0139] The conversion box uses 19 inch standard case design, each channel shielding anti-interference design, from the safety control box using digital remote control design, through the optical fiber or Ethernet cable for remote connection and through the computer for switching control operation, at the same time in the protection of safety distance range, also can be through the button or touch screen for on-site operation, touch screen interface can real-time to the current port switching state instruction, each channel is equipped with indicator light can be convenient for remote intuitive view of its current state, red light CX-- indicates the current dielectric loss test output; green light-- indicates the current channel to ground short; yellow light PD-- indicates the current partial discharge test output. Note: two channel PD light at the same time for balance method test.

[0140] Box computer operation:

[0141] The electrical automatic conversion box uses PLC as the main logic control components, through the optical fiber communication to complete the remote isolation control, can complete the channel grounding, partial discharge test, dielectric loss test, all control parameters, operating parameters can be completed through the computer remote operation, and can real-time monitoring of the equipment running. The system has state self-checking and alarm and safety protection function, if abnormal condition occurs in the test process, the system will according to the fault type and the degree of emergency, pop-up automatic alarm interface, prompt fault reason, help the operator to quickly eliminate the corresponding equipment failure.

[0142] Example one:

[0143] DC partial discharge test, test circuit diagram is shown in Figure 3

[0144] (I) test method

[0145] ​The cabinet is placed on the side of the coupling capacitor of the direct current generator, and the output signal of the coupling capacitor is connected to the internal impedance through each input channel of the cabinet. The partial discharge output signal is output to the partial discharge instrument through the BNC partial discharge terminal on the panel, and is used to measure the partial discharge of the high-voltage test product under the direct current withstand voltage test.

[0146] (II) Test results

[0147] According to the instrument indication, discharge sound, and observation of the device body, no abnormalities were found.

[0148] The test data is shown in Table 1 below:

[0149] Channel number Test voltage value PD measurement value Result 1 CH 400 kV / 10 min Max: 17 pC Pass 2 CH 400 kV / 10 min Max: 23 pC Pass 3 CH 400 kV / 10 min Max: 12 pC Pass 4 CH 400 kV / 10 min Max: 15 pC Pass 5 CH 400 kV / 10 min Max: 44 pC Pass 6 CH 400 kV / 10 min Max: 36 pC Pass 7 CH 400 kV / 10 min Max: 12 pC Pass 8 CH 400 kV / 10 min Max: 14 pC Pass

[0150] Table 1

[0151] (III) Test conclusion

[0152] During the test, the partial discharge of each channel was affected by the external power environment and fluctuated. The overall direct current partial discharge was less than 50 pC, and the direct current partial discharge test was qualified.

[0153] Example Two:

[0154] The test circuit diagram of the alternating current partial discharge test is shown in Figure 4 .

[0155] (I) Test method The cabinet is placed on the side of the coupling capacitor of the direct current generator, and the output signal of the coupling capacitor is connected to the internal impedance through each input channel of the cabinet. The partial discharge output signal is output to the partial discharge instrument through the BNC partial discharge terminal on the panel, and is used to measure the partial discharge of the high-voltage test product under the direct current withstand voltage test.

[0156] (II) Test results

[0157] According to the instrument indication, discharge sound, and observation of the device body, no abnormalities were found.

[0158] The test data is shown in Table 2 below:

[0159] Channel number Test voltage value PD measurement value Result 1 CH 400 kV / 10 min Max: 2.03 pC Pass 2 CH 400 kV / 10 min Max: 2.01 pC Pass 3 CH 400 kV / 10 min Max: 1.19 pC Pass 4 CH 400 kV / 10 min Max: 1.25 pC Pass 5 CH 400 kV / 10 min Max: 1.93 pC Pass 6 CH 400 kV / 10 min Max: 2.01 pC Pass 7 CH 400 kV / 10 min Max: 1.19 pC Pass 8 CH 400 kV / 10 min Max: 1.06 pC Pass

[0160] Table 2

[0161] (III) Test conclusion

[0162] During the test, the partial discharge of each channel was affected by the external power environment and the test hall environment, and the cabinet was arranged in the hall connected to the high-voltage partial discharge test. The partial discharge fluctuated between 1-2 pC, which met the test requirements, and the alternating current partial discharge test was qualified.

[0163] Example Three:

[0164] The test circuit diagram of the dielectric loss test is shown in Figure 5as shown;

[0165] (I) Test method

[0166] The cabinet is placed on the side of the measured power frequency capacitor, and the dielectric loss measurement is performed with positive wiring, external standard capacitor, and high voltage test. The output signal of the measured capacitor is switched through each input channel of the cabinet and then output to the dielectric loss instrument through the CX-OUT port. The pressure is applied and the dielectric loss is tested.

[0167] (II) Test results

[0168] According to the instrument indication, discharge sound, and observation of the device body, no abnormalities were found.

[0169] The test data is shown in Table 3 below:

[0170] Channel number Unconverted device test value Converted device test value Result 1 CH Tan d: 0.059 Tan d: 0.059 Pass 2 CH Tan d: 0.055 Tan d: 0.056 Pass 3 CH Tan d: 0.029 Tan d: 0.028 Pass 4 CH Tan d: 0.025 Tan d: 0.026 Pass 5 CH Tan d: 0.014 Tan d: 0.015 Pass 6 CH Tan d: 0.017 Tan d: 0.017 Pass 7 CH Tan d: 0.099 Tan d: 0.098 Pass 8 CH Tan d: 0.101 Tan d: 0.100 Pass

[0171] Table 3

[0172] (III) Test conclusion

[0173] During the test, the channel switching was normal, and the dielectric loss test data was consistent under different voltages through channel switching, meeting the test requirements, and the dielectric loss test was qualified.

[0174] Example Four:

[0175] The test circuit diagram of the lightning operating impulse discharge test is shown in Figure 6

[0176] (I) Test method

[0177] The cabinet is placed on the side of the measured power frequency capacitor, and the dielectric loss measurement is performed with positive wiring, external standard capacitor, and high voltage test. The output signal of the measured capacitor is switched through each input channel of the cabinet and then output to the dielectric loss instrument through the CX-OUT port. The pressure is applied and the dielectric loss is tested.

[0178] (II) Test results

[0179] After the lightning and operating impulse voltage discharge test, according to the instrument indication, discharge sound, and observation of the device body, no abnormalities were found.

[0180] (III) Test conclusion

[0181] The cabinet is placed on the side of the measured power frequency capacitor, and the dielectric loss measurement is performed with positive wiring, external standard capacitor, and high voltage test. The output signal of the measured capacitor is switched through each input channel of the cabinet and then output to the dielectric loss instrument through the CX-OUT port. The pressure is applied and the dielectric loss is tested.

[0182] ​It should be pointed out that the application can be used not only for testing high-voltage bushings, but also for testing other high-voltage samples, such as high-voltage insulators, high-voltage capacitors, high-voltage arresters, high-voltage voltage dividers, high-voltage reactors, etc.

[0183] The above shows and describes the basic principles, main features and advantages of the application. Those skilled in the art should understand that the application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only to illustrate the principles of the application. Without departing from the spirit and scope of the application, various changes and improvements can be made to the application, and these changes and improvements all fall within the scope of the claimed application. The scope of protection of the application is defined by the appended claims and their equivalents.

Claims

1. A sleeve electrical test automatic transfer device, comprising a remote computer operating system, a transfer control box main body (1), a transfer control box front panel (2) and a transfer control box rear panel (3), characterized in that: The front part of the conversion control box body (1) is provided with a conversion control box front panel (2), the rear part of the conversion control box body (1) is provided with a conversion control box rear panel (3), and the inside of the conversion control box body (1) is provided with a PLC; The conversion control box front panel (2) comprises a power switch PWR (21), a power frequency impact button (22), a dielectric loss local discharge button (23), a system touch screen (24), a CX-OUT interface (25), a dielectric loss output indicator lamp (26), a dielectric loss setting button (27), a local discharge setting button (28), a local discharge output indicator lamp (29), a PD output interface (210), a first channel grounding indicator (211), a PD output grounding indicator (212), and a second channel grounding indicator (213); The conversion control box rear panel (3) comprises a first input terminal (31), a second input terminal (32), a GROUND grounding terminal (33), an Ethernet communication port (34), a STOPIN terminal (35), a cooling fan (36), a temperature controller (37), an ST expansion optical port (38), a power socket (39), and a power fuse (310); The dielectric loss setting button (27) is a button for selecting the dielectric loss output channel of the corresponding unit by clicking, and the button is a multiplexing button; the first time of clicking enables the first channel, the second time of clicking disables the first channel and enables the second channel, and the third time of clicking disables all the selected channels and grounds them; The local discharge setting button (28) is a button for selecting the local discharge output channel of the corresponding unit by clicking, and the button is a multiplexing button; the first time of clicking enables the balanced method local discharge test output, the second time of clicking disables the balanced method and enables the first channel series method local discharge test output, the third time of clicking disables the balanced method and enables the second channel series method local discharge test output, and the fourth time of clicking disables all the selected channels and grounds them.

2. The automatic switching device for electrical test of a bushing according to claim 1, characterized in that: The power switch PWR (21) is used for turning on and off the power supply of the conversion control box system; The power frequency impact button (22) is a power frequency impact selection button, and after switching, the system will automatically ground all the channels; The dielectric loss local discharge button (23) is a dielectric loss local discharge selection button, and before using the conversion box function, the button needs to be selected and placed in the ON state.

3. An automatic transfer device for electrical tests of a bushing according to claim 2, characterized in that: The system touch screen (24) is used for parameter setting of the conversion box input and output channels, system state monitoring, and system man-machine interaction; the FAULT is a channel fault warning lamp, and the COMM is a communication normal operation indicator lamp; The CX-OUT interface (25) is a conversion box dielectric loss CX output channel, and CH1, CH2, CH3, CH4, CH5, CH6, CH7 and CH8 are all output from the channel through internal switching; during measurement, the channel is strictly prohibited to be open or virtually connected; The dielectric loss output indicator lamp (26) is used for indicating the dielectric loss output state of each corresponding channel, and the lamp is red.

4. The automatic transfer device for electrical test of a bushing according to claim 3, characterized in that: The local discharge output indicator lamp (29) is used for indicating the local discharge output state of each corresponding channel, and the lamp is orange. The PD output interface (210) is a conversion box local discharge output channel, CH1-CH2, CH3-CH4, CH5-CH6, CH7-CH8 two-way one group is output from the channel through internal switching respectively; The first channel ground indication (211) is used for indicating the grounding condition of the first channel, and is displayed by a green indicating lamp; The PD output ground indication (212) is used for indicating the connection condition of the local discharge test and the loop ground, and is displayed by a green indicating lamp; The second channel ground indication (213) is used for indicating the grounding condition of the second channel, and is displayed by a green indicating lamp.

5. An automatic transfer device for electrical tests of a bushing according to claim 4, characterized in that: The first input terminal (31) comprises CH2, CH4, CH6 and CH8 channel input terminals, and high-voltage sleeves CH2, CH4, CH6 and CH8 channels are externally connected, which are marked by yellow and can be fastened by 6mm banana plugs or thread nose screws. The second input terminal (32) comprises CH1, CH3, CH5 and CH7 channel input terminals, and high-voltage sleeves CH1, CH3, CH5 and CH7 channels are externally connected, which are marked by red and can be fastened by 6mm banana plugs or thread nose screws.

6. An automatic transfer device for electrical tests of a bushing according to claim 5, characterized in that: The GROUND grounding terminal (33) is a conversion box grounding terminal, which keeps the same grounding point with the tested product ground; The Ethernet communication port (34) is used for remote access and later expansion; The STOPIN terminal (35) is a function expansion terminal, and a user can input a signal to perform linkage with other control devices; The cooling fan (36) is used for cooling the power supply and control system power supply of the isolation unit module; The temperature controller (37) is an automatic temperature monitoring device in the case, and a user can independently set the starting or stopping temperature range according to the situation; The ST expansion optical port (38) is used for system remote expansion, and is adapted to optical fiber wavelength of multimode 1310nm, fiber core diameter of 62.5μm, and transmission distance of 2kM, and is used for optical fiber communication computer remote monitoring.

7. A method for automatically switching a sleeve electrical test device, as claimed in claim 6, characterized in that, The method comprises the following steps: S1, turn on the power switch PWR (21) of the conversion control box main body (1) to power on the system, and perform parameter pre-setting of input and output channels and initial monitoring of system state through the system touch screen (24) of the front panel (2) of the conversion control box or a remote computer, so that the COMM communication normal operation indicating lamp is turned on; S2, according to the test type, select the placement position: the direct current local discharge test is placed on the side of the direct current generator coupling capacitor, the alternating current local discharge test is placed on the side of the power frequency capacitor voltage divider, the dielectric loss test is placed on the side of the power frequency tested product, and the lightning impulse discharge test is placed on the side of the lightning impulse device test product; S3, ground the conversion box through the GROUND grounding terminal (33) of the rear panel (3) of the conversion control box, and keep the same grounding point with the tested product ground. S4, signal access: the coupling capacitor output signal of the DC partial discharge test, the coupling voltage divider output signal of the AC partial discharge test, and the measured capacitor output signal of the dielectric loss test are connected to CH1-CH8 channels, wherein CH2, CH4, CH6, and CH8 channels are connected to the first input terminal (31) marked with yellow, CH1, CH3, CH5, and CH7 channels are connected to the second input terminal (32) marked with red, and a 6mm banana plug or a wire nose screw is used for fastening; the lightning impulse discharge test connects the rear sleeve input channels to the impulse test sample through the first input terminal (31) and the second input terminal (32), and shorts the test sample to the ground; S5, mode and channel setting: the dielectric loss partial discharge button (23) is set to ON state for the DC partial discharge test and the AC partial discharge test, the partial discharge setting button (28) is clicked to select the partial discharge output channel, the first time enables the balanced method partial discharge test output, the second time disables the balanced method and enables the first channel series method partial discharge test, and the third time disables the balanced method and enables the second channel series method partial discharge test; the dielectric loss test operates the dielectric loss partial discharge button (23) to be in ON state, and clicks the dielectric loss setting button (27) to select the dielectric loss output channel, the first time enables the first channel, and the second time cuts off the first channel and enables the second channel; the lightning impulse discharge test operates the power frequency impulse button (22) to switch to the power frequency impulse mode, and the system automatically grounds all channels; S6, state confirmation: the orange light of the partial discharge output indicator (29) is observed to confirm that the partial discharge output is normal, and the green indicator of the first channel grounding indication (211), the second channel grounding indication (213), and the PD output grounding indication (212) is observed to confirm that the non-selected channel grounding is normal; the red light of the dielectric loss output indicator (26) is observed to confirm that the dielectric loss output is normal; the green indicator of the first channel grounding indication (211) and the second channel grounding indication (213) is observed to confirm that all channel grounding is normal; S7, test execution and signal transmission: the partial discharge output signal is transmitted to the partial discharge instrument through the PD output interface (210) for measurement for the DC partial discharge test and the AC partial discharge test; the dielectric loss output signal is transmitted to the dielectric loss instrument through the CX-OUT interface (25) for measurement, and a positive connection, an external standard capacitor, and an external high-voltage test mode are used for pressure and test to ensure that the CX-OUT interface (25) is not open or virtually connected; the lightning impulse discharge test performs the lightning impulse test, checks the withstand voltage of the test sample, and observes the FAULT channel fault warning light and the COMM communication normal operation indicator light of the system touch screen (24) after the test is completed.

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