Intelligent auxiliary wiring device for main transformer characteristic test and control method thereof

Abstract

The invention discloses an intelligent auxiliary wiring device for a main transformer characteristic test and a control method thereof, and relates to the technical field of circuit control, the device comprises a wiring port, a switching circuit module and a central control unit; the wiring port is used for connecting each winding of the main transformer at one time; the input end of the switching circuit module is electrically connected with the wiring port, the output end of the switching circuit module is used for being connected with an external test instrument, and the switching circuit module is configured to automatically switch the electrical connection mode between each winding of the main transformer and the external test instrument according to the test type; the central control unit is electrically connected with the control end of the switching circuit module, and the central control unit is used for controlling the switching circuit module to be switched to the electrical connection mode required by the corresponding test under the condition that the target test instruction is received. Therefore, manual wiring reconnection caused by multiple times of climbing operation in each test is avoided, and the overall efficiency of the characteristic test of the main transformer is improved.

Description

Intelligent auxiliary wiring device and control method for main transformer characteristic testing Technical Field

[0001] This application relates to the field of circuit control technology, and in particular to an intelligent auxiliary wiring device and control method for main transformer characteristic testing. Background Technology

[0002] The main transformer is the core equipment in a substation. Its main function is to convert high-voltage electricity into low-voltage electricity suitable for users. If a fault occurs in the main transformer, it can lead to partial power outages, large-scale power outages, or even equipment explosions in the substation. Therefore, it is necessary to conduct regular characteristic tests on the main transformer to ensure its safe operation.

[0003] Currently, the characteristic tests of main transformers mainly involve testing personnel repeatedly climbing the transformer body to complete wiring modifications for different test items. Since the characteristic tests include at least winding DC resistance tests, short-circuit impedance tests, and on-load tap changer time waveform tests, and each characteristic test may require multiple wiring modifications, the number of times testing personnel need to climb is increased. Because the characteristic tests of main transformers require repeated climbing operations, the overall efficiency of the characteristic tests of main transformers is reduced.

[0004] The above content is only used to help understand the technical solution of this application and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this application is to provide an intelligent auxiliary wiring device and its control method for main transformer characteristic testing, which aims to solve the technical problem that the characteristic testing of main transformers requires repeated climbing operations, thus reducing the overall efficiency of the main transformer characteristic testing.

[0006] To achieve the above objectives, this application proposes an intelligent auxiliary wiring device for main transformer characteristic testing. The device includes: a wiring port, a switching circuit module, and a central control unit. The wiring port is used to connect each winding of the main transformer at once. The input terminal of the switching circuit module is electrically connected to the wiring port, and the output terminal is used to connect to external testing instruments. The switching circuit module is configured to automatically switch the electrical connection mode between each winding of the main transformer and the external testing instruments according to the test type. The central control unit is electrically connected to the control terminal of the switching circuit module. The central control unit is used to control the switching circuit module to switch to the electrical connection mode required for the corresponding test when receiving a target test command.

[0007] In one embodiment, the main transformer is a three-winding transformer, including a first winding, a second winding and a third winding, and the connection ports are electrically connected to the first winding, the second winding and the third winding respectively.

[0008] In one embodiment, the target test command includes a DC power supply test command, a short-circuit impedance test command, and an on-load tap changer timing waveform test command; the electrical connection method corresponding to the target test command includes a first wiring mode for performing a DC resistance test, a second wiring mode for performing a short-circuit impedance test, and a third wiring mode required to support the on-load tap changer operation timing test.

[0009] In one embodiment, the device further includes a human-machine interface module electrically connected to the central control unit. The human-machine interface module includes a first control area for triggering the DC power supply test command, a second control area for triggering the short-circuit impedance test command, and a third control area for triggering the on-load switching time waveform test command. The human-machine interface module is used to display the current wiring mode, test type, and switching status, and to receive the target test command triggered by the user.

[0010] In one embodiment, the device further includes an AC / DC current monitoring unit, which is connected in series in the output circuit of the switching circuit module and communicates with the central control unit. The AC / DC current monitoring unit is used to collect the current signal in the test circuit in real time and feed it back to the central control unit to verify whether the wiring status is correct.

[0011] In one embodiment, the device further includes a dual power supply management module, the output of which is electrically connected to the central control unit and the switching circuit module respectively, for providing operating power to the central control unit and the switching circuit module; the dual power supply management module is configured to prioritize the use of external power when external AC power is available, and automatically switch to built-in battery power when external power is disconnected.

[0012] Furthermore, to achieve the above objectives, this application also proposes a control method for an intelligent auxiliary wiring device for main transformer characteristic testing, applied to the central control unit of the intelligent auxiliary wiring device for main transformer characteristic testing. Each winding of the main transformer is connected to the wiring port at once. The method includes: receiving a target test command; and, based on the target test command, controlling the switching circuit module in the intelligent auxiliary wiring device for main transformer characteristic testing to switch the electrical connection mode between each winding of the main transformer and the external test instrument to form the test circuit required for the corresponding test.

[0013] In one embodiment, the step of controlling the switching circuit module in the intelligent auxiliary wiring device for main transformer characteristic testing to switch the electrical connection mode between each winding of the main transformer and the external test instrument based on the target test command includes: if the target test command is a short-circuit impedance test command, controlling the input terminals corresponding to each winding in the switching circuit module of the intelligent auxiliary wiring device for main transformer characteristic testing to simultaneously short-circuit to the corresponding busbar to form a short-circuit test circuit.

[0014] In one embodiment, the step of controlling the switching circuit module in the intelligent auxiliary wiring device for main transformer characteristic testing to switch the electrical connection mode between each winding of the main transformer and the external testing instrument based on the target test command further includes: if the target test command is a DC resistance test command, controlling the switching circuit module to sequentially conduct the independent test circuits between the first winding, the second winding and the third winding of the main transformer and the external testing instrument, and disconnecting the connection of the remaining windings before each switching.

[0015] In one embodiment, the step of controlling the switching circuit module in the intelligent auxiliary wiring device for main transformer characteristic testing to switch the electrical connection mode between each winding of the main transformer and the external testing instrument based on the target test command further includes: if the target test command is an on-load tap changer time waveform test command, controlling the switching circuit module to connect the signal acquisition channel of the external testing instrument between the moving contact and the fixed contact of the on-load tap changer of the main transformer, and keeping the remaining windings in an open circuit state.

[0016] The one or more technical solutions proposed in this application have at least the following technical effects: by setting up a one-time connection port for each winding of the main transformer, and combining it with a switching circuit module driven by the central control unit, the electrical connection mode between each winding and the external test instrument is automatically switched after receiving the target test command. Thus, the wiring configuration of various main transformer characteristic test items can be completed without the need for testing personnel to repeatedly climb the main transformer body for manual reconnection. This avoids the need for multiple climbing operations for manual wiring reconnection for each test, thereby improving the overall efficiency of the main transformer characteristic test. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 is a schematic diagram of the module of the intelligent auxiliary wiring device for main transformer characteristic testing provided in the first embodiment of this application; Figure 2 is a circuit diagram of the central control unit provided in the first embodiment of this application; Figure 3 is a circuit diagram of the switching circuit module provided in the first embodiment of this application; Figure 4 is a circuit diagram of the AC / DC current monitoring unit provided in the first embodiment of this application; Figure 5 is a circuit diagram of the dual power supply management module provided in the first embodiment of this application; Figure 6 is a flowchart of the control method of the intelligent auxiliary wiring device for main transformer characteristic testing provided in the second embodiment of this application.

[0020] The following are the reference numerals: 10, Dual power supply management module; 20, Switching circuit module; 30, Main transformer; 31, Winding; 40, AC / DC current monitoring unit; 50, External testing instrument; 60, Central control unit; 70, Human-machine interaction module.

[0021] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0023] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0024] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0025] The main transformer is the core equipment in a substation. Its main function is to convert high-voltage electricity into low-voltage electricity suitable for users. If a fault occurs in the main transformer, it can lead to partial power outages, large-scale power outages, or even equipment explosions in the substation. Therefore, it is necessary to conduct regular characteristic tests on the main transformer to ensure its safe operation.

[0026] Currently, the characteristic tests of main transformers mainly involve testing personnel repeatedly climbing the transformer body to complete wiring modifications for different test items. Since the characteristic tests include at least winding DC resistance tests, short-circuit impedance tests, and on-load tap changer time waveform tests, and each characteristic test may require multiple wiring modifications, the number of times testing personnel need to climb is increased. Because the characteristic tests of main transformers require repeated climbing operations, the overall efficiency of the characteristic tests of main transformers is reduced.

[0027] Based on this, this application provides an intelligent auxiliary wiring device for main transformer characteristic testing. Referring to Figure 1, the device includes: a wiring port, a switching circuit module 20, and a central control unit 60. The wiring port is used to connect each winding 31 of the main transformer 30 at once. The input terminal of the switching circuit module 20 is electrically connected to the wiring port, and the output terminal is used to connect to an external testing instrument 50. The switching circuit module 20 is configured to automatically switch the electrical connection mode between each winding 31 of the main transformer 30 and the external testing instrument 50 according to the test type. The central control unit 60 is electrically connected to the control terminal of the switching circuit module 20. The central control unit 60 is used to control the switching circuit module 20 to switch to the electrical connection mode required for the corresponding test when a target test command is received.

[0028] It should be noted that the main transformer 30 is the core equipment in the power system used for voltage level transformation, and typically includes at least two windings 31. The wiring ports are a set of physical electrical interfaces on the device, used to establish a fixed connection with all the windings 31 under test of the main transformer 30 in a single operation. The switching circuit module 20 is a programmable circuit network composed of multiple controllable electronic switches. The switching circuit module 20 can dynamically reconstruct its internal paths according to control signals, realizing a specified electrical connection topology between different windings 31 and the test instrument. The central control unit 60 is an embedded microcontroller system used to receive user instructions or preset programs, parse the target test type, and generate corresponding control signals to drive the switching circuit module 20 to perform wiring mode switching. The target test instruction is a digital instruction indicating the execution of a specific transformer characteristic test. The electrical connection method refers to the specific circuit connection relationship required between each winding 31 of the main transformer 30 and the external test instrument 50 under specific test conditions.

[0029] Understandably, by controlling the switching circuit module 20 to switch the electrical connection method required for the test according to the needs of the test, the central control unit 60 allows the operator to connect all windings 31 of the main transformer 30 to the wiring ports at once before the test. Subsequent wiring changes required for different test items are all automatically completed by the central control unit 60 controlling the switching circuit module 20, eliminating the need for repeated manual disassembly and reassembly of test leads. This avoids frequent manual wiring changes during the characteristic test of the main transformer 30, thus avoiding inefficiency, cumbersome operation, and high risk of incorrect wiring, and improving on-site testing efficiency and operational safety.

[0030] This embodiment provides an intelligent auxiliary wiring device for the characteristic test of a main transformer 30. By setting a one-time connection to the wiring ports of each winding 31 of the main transformer 30, and combining it with the switching circuit module 20 driven by the central control unit 60, the device automatically switches the electrical connection mode between each winding 31 and the external test instrument 50 after receiving the target test command. Thus, the wiring configuration for various characteristic tests of the main transformer 30 can be completed without the need for testing personnel to repeatedly climb the main transformer 30 body for manual rewiring. This avoids the need for multiple climbing operations for manual wiring rewiring for each test, thereby improving the overall efficiency of the characteristic test of the main transformer 30.

[0031] Furthermore, the switching circuit module 20 can automatically construct the corresponding electrical connection method according to different test types (such as DC resistance test, short-circuit impedance test, and on-load switching time waveform test), ensuring that the wiring topology of each test strictly conforms to the requirements of the standard procedure. In practical applications, this setting can avoid wiring errors caused by insufficient human experience or negligence, thereby improving the accuracy and repeatability of test data.

[0032] Understandably, by embedding the wiring logic into the central control unit 60 and having it centrally schedule the process, the entire testing procedure can be highly standardized and programmable. This setup, in practical applications, not only reduces reliance on operators' specialized skills but also provides the hardware foundation for a fully automated transformer comprehensive characteristic testing system, thereby improving the intelligence of condition-based maintenance of power equipment.

[0033] In the specific implementation, after the switching circuit module 20 completes the switching, the central control unit 60 can also control the AC / DC current monitoring unit 40 to inject microampere-level test current. By detecting the circuit impedance or current path, it can automatically determine whether the wiring is consistent with the expectation. If there is an abnormality (such as open circuit or short circuit error), an alarm will be set and the high-voltage test will be prohibited from starting.

[0034] Furthermore, the main transformer 30 is a three-winding transformer 31, including a first winding, a second winding and a third winding, and the connection ports are electrically connected to the first winding, the second winding and the third winding respectively.

[0035] It should be noted that a three-winding 31 transformer is a power transformer with three independent windings 31, which may include a high-voltage winding, a medium-voltage winding, and a low-voltage winding, all of which share the same core magnetic circuit. Specifically, the first winding can correspond to the high-voltage winding, the second winding can correspond to the medium-voltage winding, and the third winding can correspond to the low-voltage winding. An electrical connection is a low-impedance path formed between two components through a conductor, allowing current to flow between them.

[0036] Understandably, the operation of the three-winding 31 transformer characteristic test is cumbersome, time-consuming, and prone to errors due to the large number of windings 31 and the complex wiring relationship. Therefore, by making a primary electrical connection between the first winding, the second winding, and the third winding and the wiring port, the circuit required for different characteristic tests of the three-winding 31 transformer can be switched through the central control unit 60 during the subsequent test, thereby improving the efficiency and safety of the on-site test.

[0037] In practical implementation, when the device is powered on for the first time, low-voltage test signals can be injected into each channel to automatically detect the number of windings 31, phase sequence, presence of a neutral point, and insulation status between windings 31, and dynamically generate a wiring mapping table to adapt to three-winding 31 transformers from different manufacturers and with different wiring groups.

[0038] Furthermore, the target test instructions include DC power supply test instructions, short-circuit impedance test instructions, and on-load tap changer timing waveform test instructions; the electrical connection methods corresponding to the target test instructions include a first wiring mode for performing DC resistance tests, a second wiring mode for performing short-circuit impedance tests, and a third wiring mode required to support on-load tap changer operation timing tests.

[0039] It should be noted that the DC resistance test command is used to initiate the DC resistance measurement of winding 31 of the main transformer 30. The short-circuit impedance test command is used to initiate the short-circuit impedance measurement between the two windings 31 of the main transformer 30. The on-load tap changer timing waveform test command is used to initiate the dynamic characteristic test of the on-load tap changer operation process. The first wiring mode is the electrical connection method used to perform the DC resistance test. The second wiring mode is the electrical connection method used to perform the short-circuit impedance test. The third wiring mode is the electrical connection method required to support the on-load tap changer operation timing test.

[0040] Understandably, by setting the wiring mode corresponding to different target test commands, the central control unit 60 can automatically drive the switching circuit module 20 to reconstruct the internal path according to the different target test commands received, and accurately construct an electrical connection method that strictly matches the test type, without requiring operators to memorize the complex wiring rules of various tests or manually replace test cables.

[0041] Understandably, since the waveform test of the large main transformer 30, which includes an on-load tap changer, has extremely high requirements for timing and wiring accuracy, manual operation can be avoided by setting a third wiring mode that supports the timing test of the on-load tap changer operation, thereby ensuring the consistency of the on-load tap changer timing waveform test.

[0042] In the specific implementation, in order to realize the automatic switching of various connection states such as short circuit, grounding, and floating between the three-phase windings 31 of the transformer, and to adapt to the connection requirements of different test items such as DC resistance, short circuit impedance, and on-load switching time waveform, referring to Figure 2, the switching circuit module 20 has multiple sets of JX30F type switching relays built in, covering the connection branches of the high-voltage side, medium-voltage side, and low-voltage side windings 31. After receiving the instruction from the central control unit 60, the relay control unit realizes the connection state switching through the logical combination of relay activation and deactivation.

[0043] Furthermore, the device also includes a human-machine interface module 70, which is electrically connected to the central control unit 60. The human-machine interface module 70 includes a first control area for triggering the DC power supply test command, a second control area for triggering the short-circuit impedance test command, and a third control area for triggering the on-load switching time waveform test command. The human-machine interface module 70 is used to display the current wiring mode, test type, and switching status, and to receive the target test command triggered by the user.

[0044] It should be noted that the human-machine interface module 70 is a user operation and information feedback interface unit, used to receive user input operation commands and present the system operating status to the user. The first control area is a physical or virtual operation area on the human-machine interface module 70 specifically for triggering DC resistance test commands, including high-voltage side DC resistance, medium-voltage side DC resistance, and low-voltage side DC resistance. The second control area is an operation area on the human-machine interface module 70 specifically for triggering short-circuit impedance test commands, including high-to-medium short-circuit impedance, high-to-low short-circuit impedance, and medium-to-low short-circuit impedance. The third control area is an operation area on the human-machine interface module 70 specifically for triggering on-load tap changer time waveform test commands, used to initiate dynamic characteristic testing of the on-load tap changer operation process. The current wiring mode is the current electrical connection topology state of the switching circuit module 20. The test type is the real-time operating status of the relays or electronic switches inside the switching circuit module 20.

[0045] Understandably, users can quickly select the target test type through intuitive partition controls without having to memorize complex commands or navigate multi-layered menus, thus lowering the operational threshold. At the same time, since each control area corresponds one-to-one with a specific test instruction, it can effectively avoid misselection or confusion of different test modes, thereby improving operational accuracy.

[0046] Understandably, the human-machine interface module 70 displays the current wiring mode, test type, and switching status in real time. In practical applications, it also enables operators to clearly understand the current working stage of the device, avoiding accidental activation of high-voltage equipment before the switching is completed, thereby improving the safety of on-site operations.

[0047] It is understandable that integrating command input and status feedback into the same human-machine interaction module 70 and forming a closed-loop communication with the central control unit 60 can also realize the visualization, controllability and traceability of the test process in practical applications, which not only improves the efficiency of a single test, but also provides data support for fault analysis and quality audit.

[0048] In its implementation, referring to Figure 3, the core hardware component of the central control unit 60 is an STM32F103RBT6 microcontroller, coupled with peripheral power supply circuits, key input circuits, serial communication circuits, and LCD display interface circuits. The microcontroller, acting as the instruction core, receives test item selection signals and issues wiring switching commands, and communicates with the LCD display module via the serial port to achieve real-time feedback of the test status.

[0049] Furthermore, the device also includes an AC / DC current monitoring unit 40, which is connected in series in the output circuit of the switching circuit module 20 and is communicatively connected to the central control unit 60. It is used to collect the current signal in the test circuit in real time and feed it back to the central control unit 60 to verify whether the wiring status is correct.

[0050] It should be noted that the AC / DC current monitoring unit 40 is a sensing and processing module used for real-time detection of current signals in the test circuit, capable of simultaneously measuring the amplitude, direction, and waveform characteristics of both AC and DC currents. The wiring status refers to whether the electrical connection topology constructed by the current switching circuit module 20 is consistent with the wiring pattern required by the target test instruction.

[0051] Understandably, the central control unit 60 can automatically determine whether the current electrical connection is consistent with the wiring method required by the target test command by analyzing the current signal fed back from the AC / DC current monitoring unit 40 after each switch of wiring mode. For example, in a DC resistance test, if an induced current is detected in the non-test winding 31, it can be determined that it is not effectively isolated and there is a risk of wiring error.

[0052] Understandably, when the relay in the switching circuit module 20 becomes stuck, has a loose connection, or loses control signal, the abnormality can be detected in time by feeding back the current to the central control unit 60 through the AC / DC current monitoring unit 40, thereby avoiding equipment damage or personal safety accidents caused by starting a high-voltage test under incorrect wiring.

[0053] Understandably, since the AC / DC current monitoring unit 40 supports a wide range of AC / DC current measurement, it can be compatible with the wiring verification requirements of various test types in practical applications. There is no need to configure dedicated detection circuits for different tests, thereby improving the versatility and integration of the intelligent auxiliary wiring device for the characteristic test of the main transformer 30.

[0054] In the specific implementation, to achieve high-precision monitoring of the current within the range of 500mA to 50A (accuracy ±1%), and to provide a basis for judging the stability of the test process and verifying the correctness of the wiring, as shown in Figure 4, it mainly consists of an HBC-LSP type current sensor, an AD7705 type analog-to-digital converter chip, a REF3125 type reference voltage chip, and an OP07 operational amplifier. The current sensor collects the AC and DC current signals in the test circuit. After signal conditioning by the operational amplifier, the analog quantity is converted into a digital quantity by the analog-to-digital converter chip and transmitted to the central control unit 60.

[0055] Furthermore, the device also includes a dual power supply management module 10, the output of which is electrically connected to the central control unit 60 and the switching circuit module 20 respectively, for providing working power to the central control unit 60 and the switching circuit module 20; the dual power supply management module 10 is configured to prioritize the use of external power when external AC power is available, and automatically switch to built-in battery power when external power is disconnected.

[0056] It should be noted that the dual-power supply management module 10 is a power management unit with dual inputs, automatic switching, and regulated output. Its input terminals can be connected simultaneously or selectively to an external AC power source and an internal battery, while its output terminal provides a stable DC voltage to power the internal electronic modules of the device. The external AC power source is a standard industrial frequency AC power source from the local mains or a mobile generator, serving as the primary power source for the device.

[0057] Understandably, through the dual power supply management module 10, the device can still maintain the continuous operation of the central control unit 60 and the state of the switching circuit module 20 by relying on the built-in battery in complex power supply environments such as substation maintenance, temporary power outages, or no mains power in the field, thus avoiding interruption of the test process, loss of wiring status, or reset of control logic due to power interruption.

[0058] In the specific implementation, a stable operating voltage is provided for the central control unit 60, relays, current acquisition units, and other functional modules to ensure reliable operation of the instrument under different power supply scenarios. Referring to Figure 5, the dual power supply management module 10 supports external 220V AC power or internal 24V DC battery input. The core components are the LM2576S-5 voltage regulator chip and the A0515S DC-DC converter chip. The input voltage is regulated by the LM2576S-5 to output a 5V reference voltage, which is then converted to a secondary voltage through the ASM1117 chip and the A0515S chip.

[0059] This application also provides a control method for an intelligent auxiliary wiring device for main transformer characteristic testing. Referring to Figure 6, which is a flowchart of the first embodiment of the control method for the intelligent auxiliary wiring device for main transformer characteristic testing of this application.

[0060] In this embodiment, the method is applied to the central control unit of the intelligent auxiliary wiring device for main transformer characteristic testing. Each winding of the main transformer is connected to the wiring port at once. The control method of the intelligent auxiliary wiring device for main transformer characteristic testing includes steps S10 to S20: Step S10, receiving the target test command; it can be understood that by receiving the target test command, the central control unit can accurately know the type of test that the user needs to perform, thereby providing a clear control basis for subsequent automated wiring switching, so that the entire test process is transformed from passive manual operation to controlled procedural execution, avoiding the error in test type selection due to insufficient experience or negligence of the operator, thereby improving the accuracy and reliability of test initiation.

[0061] Step S20: Based on the target test command, control the switching circuit module in the intelligent auxiliary wiring device for main transformer characteristic test to switch the electrical connection mode between each winding of the main transformer and the external test instrument to form the test circuit required for the corresponding test.

[0062] It should be noted that a test circuit is a complete current or signal flow path constructed to complete a specific test.

[0063] Understandably, since the windings of the main transformer have been physically connected once through the wiring ports before the test, when switching between different test items, operators do not need to repeatedly touch the high-voltage terminals or disassemble and reassemble the test leads. The test circuit can be reconstructed within seconds by sending a control signal from the central control unit. This not only greatly shortens the test preparation time and improves the efficiency of the test, but also reduces the risk of electric shock during on-site operations and improves the overall safety of the test.

[0064] This embodiment provides a control method for an intelligent auxiliary wiring device for main transformer characteristic testing. During the main transformer characteristic test, the device receives the target test command and controls the switching circuit module in the intelligent auxiliary wiring device accordingly to automatically switch the electrical connection mode between each winding of the main transformer and the external test instrument to form the test circuit required for the corresponding test. This avoids the need for testing personnel to repeatedly climb the main transformer body to manually reconnect the wiring, thereby improving the overall efficiency of the main transformer characteristic test while ensuring operational safety.

[0065] Furthermore, step S20 also includes: if the target test command is a short-circuit impedance test command, the input terminals of each winding in the switching circuit module of the intelligent auxiliary wiring device for controlling the main transformer characteristic test are simultaneously short-circuited to the corresponding busbar to form a short-circuit test loop.

[0066] It should be noted that the busbar is a low-impedance conductive busbar set inside the switching circuit module.

[0067] Understandably, by controlling the switching circuit module to simultaneously short-circuit the input terminals of each phase of the winding under test to the corresponding busbar after receiving the short-circuit impedance test command, a short-circuit test circuit that meets the standard requirements can be quickly and reliably constructed. This avoids the cumbersome and safety hazards of manually using short-circuit wires to perform three-phase binding operations, thereby improving the efficiency of short-circuit impedance testing of the main transformer.

[0068] Understandably, simultaneous engagement can prevent measurement distortion or equipment damage caused by non-full-phase short circuits.

[0069] In practice, before the switching circuit module performs the short-circuit operation, it can first confirm through the voltage monitoring unit that there is no residual voltage in the short-circuited winding; if the induced voltage is detected to exceed the safety threshold, the short-circuit operation is delayed and the discharge circuit is started to prevent arcing from damaging the contacts.

[0070] Furthermore, step S20 also includes: if the target test command is a DC resistance test command, controlling the switching circuit module to sequentially connect the independent test circuits between the first winding, the second winding and the third winding of the main transformer and the external test instrument, and disconnecting the connection of the remaining windings before each switch.

[0071] It should be noted that the independent test circuit only includes a closed current path between the winding under test and the external DC resistance tester; the other windings are completely electrically isolated and do not participate in current flow.

[0072] Understandably, by disconnecting the connection of the other windings before each independent test circuit of a certain winding is turned on, it is possible to effectively avoid the induced electromotive force generated by the untested winding due to magnetic coupling, thereby preventing the electromotive force from being superimposed on the measurement circuit and causing distortion of the DC resistance reading, and significantly improving the measurement accuracy.

[0073] It is understandable that by combining the sequential switching on and off of the remaining windings before switching to form a specific operation sequence, the core control logic can prevent mutual inductance between windings from interfering with the DC resistance measurement results, thereby improving the test accuracy.

[0074] In practical implementation, the circuit module can also use a self-locking solid-state relay. Since the static power consumption of the self-locking solid-state relay is extremely low, it can maintain the isolation state of the current winding for a long time even in battery-powered mode, thereby ensuring the stability of continuous testing of multiple windings.

[0075] Furthermore, step S20 also includes: if the target test command is an on-load switching time waveform test command, controlling the switching circuit module to connect the signal acquisition channel of the external test instrument between the moving contact and the fixed contact of the on-load tap changer in the main transformer, and keeping the remaining windings in an open circuit state.

[0076] It should be noted that an on-load tap changer is an electromechanical device installed on the windings of the main transformer (usually the high-voltage side). Fixed contacts are stationary conductive terminals in an on-load tap changer that correspond one-to-one with each tap contact.

[0077] In practical implementation, by connecting the moving / fixed contacts and other windings with an open circuit, stray currents or induced voltages can be avoided from interfering with waveform acquisition, thus providing stable data for obtaining effective time waveforms.

[0078] It should be noted that the above examples are only for understanding this application and do not constitute a limitation on the control method of the intelligent auxiliary wiring device for main transformer characteristic testing in this application. Any simple modifications based on this technical concept are within the protection scope of this application.

[0079] The above description is only a part of the embodiments of this application and does not limit the scope of protection of this application. All equivalent structural transformations made under the technical concept of this application and using the content of this application specification and drawings, or direct / indirect applications in other related technical fields, are included in the scope of protection of this application.

Claims

1. An intelligent auxiliary wiring device for main transformer characteristic testing, characterized in that, The device includes: a wiring port, a switching circuit module, and a central control unit; the wiring port is used to connect each winding of the main transformer at once; the input terminal of the switching circuit module is electrically connected to the wiring port, and the output terminal is used to connect to external testing instruments; the switching circuit module is configured to automatically switch the electrical connection mode between each winding of the main transformer and the external testing instruments according to the test type; the central control unit is electrically connected to the control terminal of the switching circuit module, and the central control unit is used to control the switching circuit module to switch to the electrical connection mode required for the corresponding test when receiving a target test command.

2. The apparatus as claimed in claim 1, characterized in that, The main transformer is a three-winding transformer, including a first winding, a second winding and a third winding, and the connection ports are electrically connected to the first winding, the second winding and the third winding respectively.

3. The apparatus as described in claim 1, characterized in that, The target test instructions include DC power supply test instructions, short-circuit impedance test instructions, and on-load tap changer timing waveform test instructions; the electrical connection methods corresponding to the target test instructions include a first wiring mode for performing DC resistance tests, a second wiring mode for performing short-circuit impedance tests, and a third wiring mode required to support on-load tap changer operation timing tests.

4. The apparatus as described in claim 3, characterized in that, The device further includes a human-machine interface module, which is electrically connected to the central control unit. The human-machine interface module includes a first control area for triggering the DC power supply test command, a second control area for triggering the short-circuit impedance test command, and a third control area for triggering the on-load switching time waveform test command. The human-machine interface module is used to display the current wiring mode, test type, and switching status, and to receive the target test command triggered by the user.

5. The apparatus as claimed in claim 1, characterized in that, The device also includes an AC / DC current monitoring unit, which is connected in series in the output circuit of the switching circuit module and communicates with the central control unit. It is used to collect the current signal in the test circuit in real time and feed it back to the central control unit to verify whether the wiring status is correct.

6. The apparatus as claimed in claim 1, characterized in that, The device further includes a dual power supply management module, the output of which is electrically connected to the central control unit and the switching circuit module respectively, for providing working power to the central control unit and the switching circuit module; the dual power supply management module is configured to prioritize the use of external power when external AC power is available, and automatically switch to built-in battery power when external power is disconnected.

7. A control method for an intelligent auxiliary wiring device for main transformer characteristic testing, applied to the central control unit of the intelligent auxiliary wiring device for main transformer characteristic testing, wherein each winding of the main transformer is connected to the wiring port at once, characterized in that, The method includes: receiving a target test command; and, based on the target test command, controlling the switching circuit module in the intelligent auxiliary wiring device for main transformer characteristic testing to switch the electrical connection mode between each winding of the main transformer and the external test instrument to form the test circuit required for the corresponding test.

8. The method as described in claim 7, characterized in that, The step of controlling the switching circuit module in the intelligent auxiliary wiring device for main transformer characteristic testing to switch the electrical connection mode between each winding of the main transformer and the external test instrument based on the target test command includes: if the target test command is a short-circuit impedance test command, controlling the input terminal of each winding in the switching circuit module of the intelligent auxiliary wiring device for main transformer characteristic testing to be simultaneously short-circuited to the corresponding busbar to form a short-circuit test circuit.

9. The method as described in claim 8, characterized in that, The step of controlling the switching circuit module in the intelligent auxiliary wiring device for main transformer characteristic testing to switch the electrical connection mode between each winding of the main transformer and the external test instrument based on the target test command further includes: if the target test command is a DC resistance test command, controlling the switching circuit module to sequentially conduct the independent test circuits between the first winding, the second winding and the third winding of the main transformer and the external test instrument, and disconnecting the connection of the remaining windings before each switching.

10. The method as described in claim 8, characterized in that, The step of controlling the switching circuit module in the intelligent auxiliary wiring device for main transformer characteristic testing to switch the electrical connection mode between each winding of the main transformer and the external test instrument based on the target test command further includes: if the target test command is an on-load tap changer time waveform test command, controlling the switching circuit module to connect the signal acquisition channel of the external test instrument between the moving contact and the fixed contact of the on-load tap changer of the main transformer, and keeping the remaining windings in an open circuit state.

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