A tap changer testing system, method, electronic device and storage medium

Abstract

The application relates to the technical field of tap changers, and provides a tap changer test system and method, electronic equipment and a storage medium, the tap changer test system comprising a tap changer, an inverter unit, a rectifier unit and a control unit, the DC side of the inverter unit being connected with the DC side of the rectifier unit, the AC side of the inverter unit comprising a first output end and a second output end, the tap changer being connected in series between the first output end, the second output end and the AC side of the rectifier unit, and the control unit being used for controlling the inverter unit to adjust a test electric signal output by the inverter unit. In the application, a power circulation is formed through the inverter unit, the tap changer and the rectifier unit, the demand of the test on the power of an AC power grid is reduced, the problem that the power is limited in the test of a large-capacity on-load voltage regulating tap changer is effectively solved, the test electric signal is adjusted through the control unit, the test electric signal can simulate a complex power grid form in full working conditions, and then the full working condition dynamic and static switching performance test of the tap changer can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tap changer, and particularly relates to a tap changer test system and method, an electronic device and a storage medium. BACKGROUND

[0002] An on-load tap changer (OLTC) is a key component of an on-load tap changer transformer, which can change its own winding turn ratio to adjust the output voltage without interrupting the load current (i.e., without power interruption), and is an important voltage regulating device in a power system. In recent years, on the one hand, with the increasing regulation tasks of the power grid, the operation frequency of the on-load tap changer of the transformer gradually increases, and the wear and failure of the tap changer also increase, and the workload of operation detection and maintenance is increasingly heavy. On the other hand, with the rapid development of power grid construction and new energy industry, the use environment of the on-load tap changer of the large-capacity transformer is becoming increasingly complex, and the requirements for the electrical parameters and service life of the on-load tap changer are constantly improving, so it is necessary to fully test the on-load tap changer as much as possible, and higher requirements are put forward for the test system and method of the tap changer.

[0003] The existing test method for the on-load tap changer of the large-capacity transformer is relatively mature, but there are still many technical limitations and deficiencies in actual application. Limited by the capacity of the power grid, the actual operating environment of the tap changer cannot be fully simulated, so it is difficult to fully meet the full-condition static and dynamic switching performance test requirements of the on-load tap changer, and the adaptability and reliability of the on-load tap changer in the complex environment on site cannot be fully verified. SUMMARY

[0004] Therefore, the present application provides a tap changer test system and method, an electronic device, a storage medium and a computer program product, which can solve the problem that the existing on-load tap changer test system and method are limited by the capacity of the power grid and cannot fully simulate the full-condition operating environment of the on-load tap changer, so that the full-condition static and dynamic switching performance test requirements of the on-load tap changer cannot be met.

[0005] Some embodiments of the present application provide a tap changer test system and method, an electronic device, a storage medium and a computer program product. The following introduces the present application from multiple aspects, and the embodiments and advantages of the following multiple aspects can be referred to each other.

[0006] In a first aspect, the present application provides a tap changer test system, comprising:

[0007] The tap changer comprises two switch input ends, one switch output end, two switch input ends are electrically connected, and a plurality of switching circuits are arranged between two switch input ends and the switch output end.

[0008] The inverter unit is used for converting direct current into alternating current output, and the alternating current side of the inverter unit comprises a first output end, a second output end and a third output end, the first output end and the second output end are connected with the two switch input ends one by one.

[0009] The rectifier unit is used for converting alternating current into direct current output, and the alternating current side of the rectifier unit comprises a first input end and a second input end, the second input end is connected with the third output end, the first input end is connected with the switch output end, and the direct current side of the rectifier unit is connected with the direct current side of the inverter unit.

[0010] The control unit is in communication connection with the inverter unit, is used for controlling the inverter unit to dynamically adjust the test electric signal output by the inverter unit based on the test environment to be provided, obtaining test data of the tap changer under the test electric signal, and analyzing the reliability of the tap changer under the full working condition operation environment based on the test data; the test data comprises all test data of the dynamic switching process of the plurality of switching circuits.

[0011] According to the embodiments of the present application, the above technical solutions of the present application at least have one of the following beneficial effects:

[0012] The tap changer to be tested is connected between the output end of the inverter unit and the input end of the rectifier power supply, and the output end of the rectifier power supply is connected with the input end of the inverter unit, forming a power circulation circuit for testing the tap changer, and the test electric signal output by the inverter unit is dynamically adjusted by the control unit, and through power circulation, the capacity demand of the alternating current grid in the test process is effectively reduced, the problem of power limitation in the test of large-capacity on-load voltage regulating tap changer caused by limited capacity of the power grid is solved, and on this basis, the full working condition operation environment of the tap changer is fully simulated through dynamic adjustment of the test electric signal, the full working condition dynamic and static test of the tap changer is realized, the adaptability and reliability of the tap changer in the complex operation environment in the field are fully verified, and the correlation model built based on the correlation between the test data and the corresponding fault risk can be used for fault risk prediction of the tap changer in the actual operation environment, improving the problem of lag of the state evaluation of the tap changer, and realizing predictive maintenance of the tap changer.

[0013] In a possible implementation of the above first aspect, the parameters of the test electric signal include at least one of a fundamental wave voltage amplitude, a fundamental wave current amplitude, a harmonic component and a fundamental wave frequency.

[0014] In a possible implementation of the first aspect, the first output end and the second output end output alternating voltages with the same phase and different amplitudes, and the phase difference between the alternating voltage output by the first output end or the second output end and the alternating voltage output by the third output end is 120°.

[0015] According to the embodiments of the present application, the alternating voltages output by the first output end and the second output end of the two different tapping taps of the transformer winding in the actual application scenario of the tapping switch can be simulated to have the same phase and different amplitudes, and the situation that the voltage output by the single-phase winding tapping tap of the transformer in the alternating power grid has a 120° phase difference with other phase windings can be simulated, so that the actual application scenario of the tapping switch can be comprehensively simulated.

[0016] In a possible implementation of the first aspect, the control unit is in communication connection with the rectifier unit, and the control unit is configured to control the rectifier unit to adjust the input parameter on the alternating side of the rectifier unit based on the test electrical signal, so that the rectifier unit is adapted to the test electrical signal output by the inverter unit and feeds back electrical energy to the inverter unit.

[0017] In a possible implementation of the first aspect, the tapping switch test system further includes a power access unit, the power access unit is configured to connect to an external alternating power grid and output direct current, and the direct current output end of the power access unit is connected to a direct current bus, and the direct current bus is connected to the direct current side of the inverter unit.

[0018] In a possible implementation of the first aspect, the power access unit includes a grid access unit and an energy storage unit.

[0019] The grid access unit includes an alternating current input end and a direct current output end, and is configured to convert alternating current into direct current and output the direct current, the alternating current input end is connected to the alternating power grid, and the direct current output end is connected to the direct current bus; the energy storage unit is connected to the direct current bus and is configured to charge and discharge relative to the direct current bus to clamp the voltage of the direct current bus at a preset voltage value. Thus, the direct current bus provides better power quality for the tapping switch test, and can also reduce the disturbance of dynamic switching on the voltage of the direct current bus during the tapping switch test, thereby reducing the impact on the alternating power grid; the energy storage unit supplements electrical energy, further reducing the power demand of the tapping switch test on the alternating power grid.

[0020] In a possible implementation of the first aspect, the energy storage unit includes a bidirectional DC-DC converter and an energy storage device, one side of the bidirectional DC-DC converter is connected to the direct current bus, and the other side of the bidirectional DC-DC converter is connected to the energy storage device.

[0021] In a possible implementation of the first aspect, the control unit is in communication connection with the bidirectional DC-DC converter and is configured to control the bidirectional DC-DC converter to work in a charging mode or a discharging mode.

[0022] In a second aspect, the present application provides a tap changer testing method applied to a tap changer testing system, the tap changer testing system comprising an inverter unit, a rectifier unit, a control unit and a tap changer, a DC side of the inverter unit being connected with an external power supply and a DC side of the rectifier unit, an AC side of the inverter unit comprising a first output end, a second output end and a third output end, the tap changer being connected in series on an electric energy transmission path between the first output end, the second output end and the AC side of the rectifier unit, the tap changer comprising a plurality of switching circuits, and the third output end being connected with the AC side of the rectifier unit, the method comprising:

[0023] The control unit determines a current testing environment to be provided, and controls the inverter unit to adjust a testing electric signal output to the tap changer in real time based on the testing environment, so as to provide different testing environments for the tap changer.

[0024] The control unit controls the rectifier unit to adjust an AC side input parameter of the rectifier unit, so as to adapt the testing electric signal output by the inverter unit and feed back electric energy to the inverter unit.

[0025] The control unit acquires testing data of the tap changer under the testing electric signal based on the testing environment and in response to the tap changer being in a steady state running state or a dynamic switching state, and analyzes reliability of the tap changer based on the testing data; the testing data comprises all testing data of a dynamic switching process of the plurality of switching circuits.

[0026] In a possible implementation of the second aspect, the testing data comprises electric data and sensing data.

[0027] The electric data comprises voltage data, current data and frequency data of the plurality of switching circuits, and the electric data is used to evaluate electrical performance and mechanical performance of the tap changer.

[0028] The sensing data comprises vibration signals of the tap changer and switching times, and the sensing data is used to evaluate the mechanical performance of the tap changer.

[0029] In a possible implementation of the second aspect, the control unit controls the inverter unit to adjust the testing electric signal output to the tap changer in real time based on the testing environment, comprising:

[0030] When the testing environment is a static testing environment, the control unit controls the inverter unit to adjust the testing electric signal output based on the static testing environment in response to the tap changer being in a steady state running state.

[0031] And / or, when the testing environment is a dynamic testing environment, the control unit controls the inverter unit to continuously adjust the testing electric signal output in real time based on the dynamic testing environment in response to the tap changer being in a dynamic switching state.

[0032] In a possible implementation of the second aspect, the reliability of the tap changer is analyzed based on the test data, including:

[0033] The control unit analyzes the electrical performance, mechanical performance, electrical life and mechanical life of the tap changer based on the test data;

[0034] The control unit determines whether the tap changer has a risk of failure;

[0035] In the case where the tap changer has no risk of failure, the control unit generates a test report;

[0036] In the case where the tap changer has a risk of failure, the control unit generates a test report and issues a failure warning.

[0037] In a possible implementation of the second aspect, the tap changer test method further includes:

[0038] If the tap changer has a risk of failure, the control unit builds a failure risk prediction model based on the correspondence between the test data and the risk of failure, and the failure risk prediction model is used to predict the risk of failure of the tap changer under real working conditions.

[0039] In a third aspect, the present application provides an electronic device, which includes a processor and a memory, and the memory stores at least one instruction or at least one program, and the at least one instruction or at least one program is loaded and executed by the processor to implement the tap changer test method disclosed in the second aspect and any possible implementation of the second aspect.

[0040] In a fourth aspect, the present application provides a computer readable storage medium, which stores at least one instruction or at least one program, and the at least one instruction or at least one program is loaded and executed by the processor to implement the tap changer test method disclosed in the second aspect and any possible implementation of the second aspect.

[0041] In a fifth aspect, the present application provides a computer program product, which includes computer instructions, and when the computer instructions run on an electronic device, the electronic device executes the tap changer test method disclosed in the second aspect and any possible implementation of the second aspect.

[0042] The beneficial effects of the second aspect to the fourth aspect can refer to the beneficial effects of the first aspect and any possible implementation of the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 FIG. 1 is a structural schematic diagram of a tap changer test system in the embodiments of the present application;

[0044] Figure 2 Fig. 1 is a connection diagram of a tap changer in an actual application scenario in an embodiment of the present application;

[0045] Figure 3 Fig. 2 is a line voltage waveform diagram between the first output end, the second output end and the third output end of an inverter unit in an embodiment of the present application;

[0046] Figure 4 Fig. 3 is a flowchart of a tap changer test method in an embodiment of the present application;

[0047] Figure 5 Fig. 4 is a flowchart of step S300 in the tap changer test method shown in Fig. 3; Figure 4

[0048] Figure 6 Fig. 5 is a structure diagram of a system on chip (SoC) in an embodiment of the present application. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0050] First, the terms involved in the present application will be explained.

[0051] Large-capacity transformer: A large-capacity transformer is the core hub of a power grid, usually referring to a power transformer with a voltage level of 110 kV and above and a capacity of tens to hundreds of megavolt-amperes. It realizes efficient transmission and distribution of electric energy through electromagnetic induction, and its core value lies in maintaining the stability of the power grid voltage by using the on-load voltage regulation function. In the power grid, it is mainly applied to the ultrahigh voltage / extra-high voltage power transmission link, as a key device of the hub substation, to realize the voltage level conversion of long-distance high-power power transmission.

[0052] On-load tap changer (OLTC): An on-load tap changer can dynamically adjust the turns ratio of the transformer winding without power interruption, thereby accurately controlling the output voltage of the transformer. In the power grid, it is mainly applied to hub substations with severe load fluctuations and the end of long-distance transmission lines, and through real-time compensation of voltage fluctuations, it guarantees the power supply quality of important users and avoids voltage collapse, which is a key device to support the safe, stable and high-quality operation of modern power grids.

[0053] ​Full-condition complex power grid morphology: The full-condition complex power grid morphology refers to the physical structure of the modern power system with high proportion of renewable energy access, multi-terminal AC / DC hybrid, and multi-element interaction of source, grid, load and storage. The core characteristics of its electrical parameters are strong uncertainty in the full domain and multi-time scale: voltage and frequency are no longer constant, but show random fluctuations; the direction and size of power flow are dynamically variable, showing multi-time scale coupling characteristics (from seconds of electromagnetic transient to hours of active power dispatch); power quality parameter indicators such as harmonics, interharmonics are multi-dimensional and wideband; system impedance characteristics are time-varying and nonlinear. These parameters are highly intertwined in time and space dimensions, making the system as a whole show high-dimensional, nonlinear and strong coupling dynamic characteristics.

[0054] Power circulation circuit: It is a circuit system that realizes energy recycling through internal closed loop, and is an active and intelligent power grid support technology. It can directly reduce the apparent power demand on the power grid and improve the overall operation efficiency of the power grid through localized energy exchange and compensation.

[0055] The existing test system and method for large-capacity on-load voltage regulating tap changer of transformer mainly has the following problems: (1) For large-capacity on-load voltage regulating tap changer, if it is applied in large-capacity transformer, the power demand corresponding to the test is also large in order to fully test and verify the reliability of the tap changer in the application scenario. However, due to the limited capacity of the power grid, the power of the tap changer during testing is limited, and the electrical and mechanical performance of the large-capacity on-load voltage regulating tap changer cannot be fully verified.

[0056] (2) The existing large-capacity on-load voltage regulating tap changer test system and method mainly focus on the static parameters of the on-load voltage regulating tap changer to judge the basic performance of the tap changer in the static and stable state, such as verifying the voltage withstand performance and insulation performance of the tap changer in the static state through AC voltage withstand test and DC resistance test. However, the good contact and qualified insulation of the tap changer in the static state cannot confirm its safety and reliability in the dynamic switching process. The existing static test system and method cannot capture the dynamic behaviors such as arc characteristics, mechanical vibration and contact bounce in the switching process, making it difficult to evaluate the performance of the on-load voltage regulating tap changer in the switching transient process, and some potential faults such as contact welding and mechanism jamming cannot be discovered in time.

[0057] At the same time, in the existing on-load voltage regulating tap changer test system and method, a direct current test method is usually adopted, which cannot simulate real scenes such as complex harmonics, transient overvoltage, unbalanced load and the like in the power grid. For example, the current impulse current test is used to verify the impact of transformer short circuit on the on-load voltage regulating tap changer, but due to the excessive impulse current, it is a destructive test, and the number of repeatable impacts is limited, so it cannot be used to study the long-term cumulative effect of non-destructive repeated current impact on the tap changer in the real operating scene.

[0058] Therefore, the existing large-capacity on-load voltage regulating tap changer has limited simulation capability for the operating environment of the tap changer, especially cannot simulate the complex power grid form in all operating conditions, so it is difficult to realize reliable verification of the tap changer in dynamic and static full operating conditions, especially it is difficult to fully verify the adaptability and reliability of the on-load voltage regulating tap changer in the complex environment on site.

[0059] (3) Since the test environment in the existing test system and method is relatively simple, and there is a big difference compared with the actual operating environment of the tap changer, the correlation model built based on the correlation between the test data of the on-load voltage regulating tap changer obtained by testing based on the existing test system and method and the corresponding fault risk cannot be used for fault risk prediction of the tap changer in the actual operating environment, resulting in that the state assessment of the tap changer lags behind in the actual operating environment, and predictive maintenance of the tap changer cannot be realized.

[0060] Therefore, in order to solve the above problems, the present application provides a tap changer test system and method, which connects the tap changer to be tested between the output end of the inverter unit and the input end of the rectifier power supply, and connects the output end of the rectifier power supply and the input end of the inverter unit, forming a power circulation circuit for testing the tap changer, and dynamically adjusting the test electric signal output by the inverter unit through the control unit, effectively reducing the capacity demand of the alternating current power grid in the test process, effectively solving the problem of power limitation in the test of large-capacity on-load voltage regulating tap changer due to limited capacity of the power grid, and on this basis, fully simulating the full operating condition of the tap changer through dynamic adjustment of the test electric signal, realizing full operating condition dynamic and static test of the tap changer, fully verifying the adaptability and reliability of the tap changer in the complex environment on site, and the correlation model built based on the correlation between the test data and the corresponding fault risk can be used for fault risk prediction of the tap changer in the actual operating environment, improving the problem of lagging behind in the state assessment of the tap changer, and realizing predictive maintenance of the tap changer.

[0061] The following will be described in detail Figures 1 to 3 The tap changer test system of the embodiment of the present application will be described in detail.

[0062] Reference Figure 1 ,Figure 2 and Figure 3 , Figure 1 The structure of the tap changer test system in the embodiment of the application is shown, Figure 2 The connection of the tap changer in the embodiment of the application in an actual application scenario is shown, Figure 3 The line voltage waveform between the first output end and the third output end of the inverter unit in the embodiment of the application, and the line voltage waveform between the second output end and the third output end are shown. In the embodiment of the application, the tap selector of the tap changer is in Figure 1 The unshown part is omitted.

[0063] As shown in Figure 1 , in the embodiment of the application, the tap changer test system comprises an inverter unit, a rectifier unit, a control unit and a tap changer.

[0064] The tap changer comprises two switch input ends, which are a first switch input end IN1 and a second switch input end IN2 respectively, and one switch output end OUT. The two switch input ends of the tap changer are electrically connected, and a plurality of switching circuits are arranged between the two switch input ends and the switch output end.

[0065] As shown in Figure 2 , the working principle and dynamic switching process of the tap changer are described in detail below by taking the tap changer in an actual application scenario as an example.

[0066] As shown in Figure 2 , the tap changer applied in the transformer comprises a tap selector and a switching switch. The tap selector comprises a moving contact and a plurality of stationary contacts. The number of the moving contact is at least two. The plurality of stationary contacts are connected to a plurality of tap heads of the transformer winding one by one in a one-to-one correspondence, and the moving contact can be switched to contact different stationary contacts.

[0067] The switching switch comprises one switch output end OUT, two connection ends and a plurality of switching circuits. When the tap changer performs on-load voltage regulation on the transformer, the switching process of the load loop is continuously connected and not short-circuited mainly by the cooperation of the plurality of switching circuits in the switching switch. The two connection ends of the switching switch are electrically connected to different moving contacts, and the plurality of switching circuits are arranged in parallel between the two connection ends of the switching switch and the switch output end OUT.

[0068] In the actual application scenario of the tap changer, the two connection ends of the switching switch can be indirectly electrically connected to different tap heads of the transformer winding by the moving contact contacting different stationary contacts. Therefore, for the tap changer, the two stationary contacts contacting the moving contact are the first switch input end IN1 and the second switch input end IN2 of the tap changer.

[0069] The plurality of switching circuits included in the tap changer are respectively a first switching circuit, a second switching circuit, a third switching circuit, a fourth switching circuit, a fifth switching circuit and a sixth switching circuit.

[0070] The first switching circuit is connected between the first switch input end IN1 and the switch output end OUT, and the first switch S1 is connected in series on the first switching circuit. The sixth switching circuit is connected between the second switch input end IN2 and the switch output end OUT, and the second switch S2 is connected in series on the sixth switching circuit.

[0071] The second switching circuit is connected between the first switch input end IN1 and the switch output end OUT, and the first single-pole double-throw switch T1 is connected in series on the second switching circuit. The common end of the first single-pole double-throw switch T1 and the switch output end OUT are connected in series with the first vacuum tube V1, and one of the tapping ends D1 of the first single-pole double-throw switch T1 is connected with the first switch input end IN1.

[0072] The third switching circuit is connected between the second switch input end IN2 and the switch output end OUT, and the first single-pole double-throw switch T1 and the first vacuum tube V1 are connected in series on the third switching circuit. The other tapping end D2 of the first single-pole double-throw switch T1 is connected in series with the second switch input end IN2 through the first resistor R1.

[0073] The fourth switching circuit is connected between the first switch input end IN1 and the switch output end OUT, and the second single-pole double-throw switch T2 is connected in series on the fourth switching circuit. The common end of the second single-pole double-throw switch T2 and the switch output end OUT are connected in series with the second vacuum tube V2, and one of the tapping ends D3 of the second single-pole double-throw switch T2 is connected in series with the first switch input end IN1 through the second resistor R2.

[0074] The fifth switching circuit is connected between the second switch input end IN2 and the switch output end OUT, and the second single-pole double-throw switch T2 and the second vacuum tube V2 are connected in series on the fifth switching circuit. The other tapping end D4 of the second single-pole double-throw switch T2 is connected with the second switch input end IN2.

[0075] When the transformer is in steady state operation, the first switching circuit or the sixth switching circuit of the tap changer is in the state of being turned on and having load current.

[0076] Taking the initial load current flowing through the first switching circuit as an example, when the on-load voltage regulation of the transformer is needed, the load current is switched from the first switching circuit to the sixth switching circuit through the cooperation of the first to sixth switching circuits. The dynamic switching process of the tap changer is described in detail below.

[0077] When the load current is long-term borne by the first switching circuit, before dynamic switching, the first vacuum tube V1 and the second vacuum tube V2 are in the on state, and the second switching circuit is turned on through the first single-pole double-throw switch T1, and the fourth switching circuit is turned on through the second single-pole double-throw switch T2. Since the first vacuum tube V1 and the second vacuum tube V2 have impedance, although the first switching circuit and the second switching circuit are both in the on state at this time, the load current is still mainly borne by the first switching circuit.

[0078] When the first switch S1 on the first switching circuit is turned off, since the second switching circuit is already in the on state, the load current is automatically switched to the second switching circuit. At this time, although the fourth switching circuit is also in the on state, the second resistance R2 is connected in series in the fourth switching circuit, so the load current mainly flows through the second switching circuit, not the fourth switching circuit.

[0079] When the first vacuum tube V1 is turned off, the load current is transferred from the second switching circuit to the fourth switching circuit. At this time, the contact of the common terminal of the first single-pole double-throw switch T1 with the tapping terminal can be switched without load current, and the common terminal of the first single-pole double-throw switch T1 is switched from being in contact with the tapping terminal D1 to being in contact with the tapping terminal D2.

[0080] The first vacuum tube V1 is turned on again, and at this time the third switching circuit is turned on, that is, the second switch input terminal IN2 connected to the third switching circuit is turned on with the switch output terminal OUT. The load current is initially only present between the first switch input terminal IN1 and the switch output terminal OUT, and is then present between the first switch input terminal IN1, the second switch input terminal IN2, and the switch output terminal OUT. At this time, the first switch input terminal IN1, the second switch input terminal IN2, and the switch output terminal OUT are mutually turned on, forming a loop current, and the presence of the first resistance and the second resistance effectively prevents the occurrence of a loop current short circuit. In this process, the load current does not interrupt.

[0081] When the second vacuum tube V2 is turned off, the load current begins to be completely borne by the third switching circuit, and the load current is initially completely input from the first switch input terminal IN1 and is then completely input from the second switch input terminal IN2.

[0082] At this time, the contact of the common terminal of the second single-pole double-throw switch T2 with the tapping terminal can be switched without load current, so that the common terminal of the second single-pole double-throw switch T2 is in contact with the tapping terminal D4, and then the second vacuum tube V2 is turned on, that is, the fifth switching circuit is turned on.

[0083] Since the fifth switching circuit is not connected in series with a resistance, and the third switching circuit is connected in series with the first resistance R1, when the fifth switching circuit is turned on, the load current is transferred from the third switching circuit to the fifth switching circuit.

[0084] At this time, the second switch S2 is closed, and the sixth switching circuit is turned on. Since the second vacuum tube V2 has impedance, when the sixth switching circuit is turned on, the load current is transferred from the fifth switching circuit to the sixth switching circuit.

[0085] At this time, the second switch S2 is closed, and the sixth switching circuit is turned on. Since the second vacuum tube V2 has impedance, when the sixth switching circuit is turned on, the load current is transferred from the fifth switching circuit to the sixth switching circuit.

[0086] In the embodiment of the present application, when the tapping switch is dynamically tested, the tapping switch is dynamically switched according to the above process, and the test data of different switching circuits in the dynamic switching process of the tapping switch is obtained by the control unit to analyze the reliability of the tapping switch.

[0087] Since in the actual application scenario, the transformer winding is connected between the two static contacts in contact with the two moving contacts, when the tapping switch is tested, the first switch input end IN1 and the second switch input end IN2 of the tapping switch need to be electrically connected as shown in Figure 1 to simulate the real application scenario of the tapping switch.

[0088] As shown in Figure 1 In the embodiment of the present application, the inverter unit is used to convert direct current into alternating current output, and the alternating current side of the inverter unit includes a first output end A1, a second output end A2 and a third output end B. The first output end A1 and the second output end A2 are connected one by one with the first switch input end IN1 and the second switch input end IN2 respectively, and the transformer winding in the actual application scenario is simulated by the first output end A1 and the second output end A2.

[0089] As shown in Figure 3 u A1B is the line voltage between the first output end A1 and the third output end B, u A2B is the line voltage between the second output end A2 and the third output end B, u A1B and u A2B have the same phase and different amplitudes.

[0090] In combination with Figure 1 and Figure 3It can be understood that when the tap changer is tested, the inverter unit outputs three-phase independent alternating current as a voltage source, wherein the alternating voltages output by the first output end A1 and the second output end A2 are of the same phase and different amplitudes, so as to simulate the regulation of the pressure difference of the tap changer in the actual application scenario. Moreover, the phase difference between the alternating voltages output by the first output end A1 and the second output end A2 and the alternating voltage output by the third output end B is 120°, so that the first output end A1 and the third output end B form a single-phase adjustable voltage source, and the second output end A2 and the third output end B form another single-phase adjustable voltage source.

[0091] In the actual application scenario of the tap changer, since different tap heads of the transformer winding are essentially connected to the same winding, the voltages output by different winding tap heads are of the same phase but different amplitudes. Therefore, in the embodiment of the present application, the alternating voltages output by the first output end A1 and the second output end A2 for simulating two different tap heads of the transformer winding in the actual application scenario are of the same phase and different amplitudes.

[0092] By controlling the phase difference between the alternating voltages output by the first output end A1 and the second output end A2 and the alternating voltage output by the third output end B to be 120°, the situation that the voltage output by the single-phase winding tap head of the transformer in the alternating current grid has a phase difference of 120° with other phase windings is simulated, and a more comprehensive simulation of the actual application scenario of the tap changer is realized.

[0093] As shown in Figure 1 In the embodiment of the present application, the rectifier unit is used to convert alternating current into direct current output. The alternating side of the rectifier unit includes a first input end a and a second input end b. The first input end a of the rectifier unit is connected to the switch output end OUT of the tap changer, the second input end b of the rectifier unit is connected to the third output end B of the inverter unit, and the direct current side of the rectifier unit is connected to the direct current side of the inverter unit. Therefore, the inverter unit, the tap changer and the rectifier unit jointly form a power circulation circuit. By realizing power circulation, the power circulation circuit effectively reduces the demand for external power supply, thereby reducing the power demand of the alternating current grid in the test process of the tap changer, and effectively solving the problem that the test power is limited by the power of the alternating current grid when the tap changer for on-load voltage regulation of a large-capacity transformer is tested.

[0094] In the embodiment of the present application, the control unit is in communication connection with the inverter unit. Based on the types of full-control and half-control devices, circuit topological structure design inside the inverter unit, and the communication connection between the control unit and the inverter unit, the control unit can control the inverter unit to dynamically adjust the test electrical signal output by the inverter unit, and the test electrical signal is output through the first output end A1, the second output end A2 and the third output end B of the inverter unit.

[0095] By dynamically adjusting the test electrical signal, including dynamically adjusting at least one of the fundamental wave voltage amplitude, the fundamental wave current amplitude, the harmonic component, and the fundamental wave frequency of the test electrical signal, full simulation of the operating environment of the tap changer under all operating conditions can be achieved, especially full simulation of the operating environment of the tap changer under complex power grid forms under all operating conditions, and then the dynamic and static full operating conditions of the tap changer can be tested, and the adaptability and reliability of the tap changer under complex full operating conditions can be fully verified.

[0096] The circuit topology structure of the inverter unit is not limited in the embodiments of the present application. For example, the circuit can be a two-level topology structure, a three-level topology structure, or a modular multi-level topology structure, etc.

[0097] In the embodiments of the present application, the control unit is in communication connection with the rectifier unit. Based on the various types of full-control and half-control devices, circuit topology structure design inside the rectifier unit, and the communication connection between the control unit and the rectifier unit, the control unit can adjust the input parameters of the first input end a and the second input end b of the rectifier unit, including voltage, current, frequency, etc., so that the rectifier unit adapts to the test electrical signal output by the inverter unit. When testing the tap changer, the rectifier unit adjusts the current through the tap changer in real time as a current source, and feeds back power to the inverter unit.

[0098] The circuit topology structure of the rectifier unit is not limited in the embodiments of the present application. For example, the circuit can be a two-level topology structure, a three-level topology structure, or a modular multi-level topology structure, etc.

[0099] The control unit is also used to obtain test data of the tap changer under the test electrical signal, and the test data is used to analyze the reliability of the tap changer. The test data includes all test data of the dynamic switching process of the plurality of switching circuits. The test data specifically includes electrical data for evaluating the electrical performance and mechanical performance of the tap changer, including voltage data, current data, and frequency data of the plurality of switching circuits of the tap changer; and sensing data for evaluating the mechanical performance of the tap changer, including vibration signals and switching times of the tap changer.

[0100] When the control unit controls the inverter unit to adjust the test electrical signal, the adjustment basis is the test environment required when different test items are performed on the tap changer. Specifically, the control unit controls the inverter unit to adjust the test electrical signal output to the tap changer in real time, so as to provide different test environments for the tap changer.

[0101] The tap changer testing system provided in this application connects the tap changer under test between the output of the inverter unit and the input of the rectifier power supply, and connects the output of the rectifier power supply to the input of the inverter unit, forming a power circulating circuit for testing the tap changer. The control unit dynamically adjusts the test signal output by the inverter unit. Through power circulation, the system effectively reduces the capacity requirement of the AC power grid during testing, solving the problem of power limitation in large-capacity on-load tap changer testing due to limited grid capacity. Furthermore, the dynamic adjustment of the test signal fully simulates the full-condition operating environment of the tap changer, enabling dynamic and static testing of the tap changer under all operating conditions. This fully verifies the adaptability and reliability of the tap changer in complex field operating environments. Moreover, the correlation model built based on the relationship between test data and corresponding fault risks can be used to predict the fault risks of the tap changer in actual operating environments, improving the current problem of lagging tap changer condition assessment and enabling predictive maintenance of the tap changer.

[0102] like Figure 1 As shown in the embodiment of this application, the tap changer testing system further includes a power supply unit. The power supply unit provides power to the power circulating circuit. The power supply unit is used to connect to an external AC power grid and output DC power. The DC output terminal of the power supply unit is connected to a DC bus, which is connected to the DC side of the inverter unit.

[0103] Therefore, the AC power supplied by the AC grid is converted into DC power by the power input unit and then output to the DC bus. The DC bus is connected to the DC side of the inverter unit, which inputs electrical energy into the inverter unit. The current flows through the inverter unit, tap changer and rectifier unit in sequence, and finally feeds back to the DC bus and inverter unit through the rectifier unit, forming a complete power circulation.

[0104] Specifically, the DC power output from the power input unit is transmitted to the power circulating circuit via the DC bus. It first needs to be input to the inverter unit via the DC side. The inverter unit converts the DC power and outputs three-phase independent AC power, which is then output through the first output terminal A1, the second output terminal A2, and the third output terminal B, respectively. The AC power output from the first output terminal A1 and the second output terminal A2 can be indirectly transmitted to the first input terminal a of the rectifier unit via a tap changer, while the AC power output from the third output terminal B is directly transmitted to the second input terminal b of the rectifier unit.

[0105] In this embodiment, the power access unit includes a grid connection unit and an energy storage unit.

[0106] The grid connection unit includes an alternating current input end and a direct current output end, and is configured to convert alternating current into direct current and output the direct current. The alternating current input end of the grid connection unit is connected to the alternating current grid, and the direct current output end is connected to the direct current bus. The alternating current provided by the alternating current grid is converted into direct current by the grid connection unit, and is output to the power circulation circuit formed by the inverter unit, the tap changer and the rectifier unit through the direct current bus, thereby providing power for testing the tap changer.

[0107] The energy storage unit is connected to the direct current bus and is configured to charge and discharge the direct current bus to clamp the voltage of the direct current bus at a preset voltage value.

[0108] It can be understood that, for the direct current bus, due to the complex operating conditions of the alternating current grid, the stability of the direct current output by the direct current output end of the grid connection unit is poor, thereby affecting the test effect of the tap changer. In the embodiment of the present application, the energy storage unit charges and discharges the direct current bus. When the voltage of the direct current bus is higher than the preset voltage value, the energy storage unit is in a charging mode and absorbs power from the direct current bus to reduce the voltage of the direct current bus. When the voltage of the direct current bus is lower than the preset voltage value, the energy storage unit is in a discharging mode and outputs power to the direct current bus to increase the voltage of the direct current bus, thereby clamping the voltage of the direct current bus. The power quality provided by the direct current bus for testing the tap changer is ensured, and the disturbance caused by the tap changer test to the direct current bus is balanced in time, thereby reducing the impact of the tap changer test on the alternating current grid.

[0109] For the alternating current grid, a plurality of loads are connected to the load side of the alternating current grid. The tap changer test system in the embodiment of the present application is one of the loads connected to the load side of the alternating current grid. The input power of the grid connection unit connected to the alternating current grid needs to be less than the rated power of the alternating current grid to ensure that other loads of the alternating current grid can operate normally.

[0110] In the embodiment of the present application, the energy storage unit supplies power to the direct current bus, which can effectively supplement the power capacity required for the tap changer test, thereby further reducing the power demand of the large-capacity on-load voltage regulating tap changer test on the grid.

[0111] In the embodiment of the present application, by connecting the energy storage unit to the direct current bus, the voltage of the direct current bus can be stabilized, the direct current bus can provide better power quality for the tap changer test, the disturbance to the voltage of the direct current bus during the tap changer test can be reduced, and the impact on the alternating current grid can be reduced. On the basis of power circulation, the energy storage unit supplements power, and further reduces the power demand of the tap changer test on the alternating current grid.

[0112] In the embodiment of the present application, the network access unit includes a power transformer, a power rectifier and a power switch.

[0113] The primary winding of the power transformer is connected to the AC power grid, the secondary winding of the power transformer is connected to the power rectifier, and the DC side of the power rectifier is connected to the DC bus.

[0114] The power switch is connected in series in the power transmission path from the AC power grid to the primary winding of the power transformer, and serves as the total power switch of the tap switch test system in the embodiment of the present application. The entire tap switch test system (including the power transformer, the power rectifier, the inverter unit, etc.) can be completely isolated from the AC power grid.

[0115] When the power switch is turned off, the entire tap switch test system is powered off, which can ensure the safety of maintenance personnel, avoid the risk of electric shock, and meet the basic requirements of electrical safety. When a fault occurs in the tap switch test system (such as transformer short circuit, power rectifier failure), the power switch can quickly cut off the power supply to prevent the fault from expanding and protect the AC power grid from impact. At the same time, it allows safe and comprehensive inspection and maintenance of the tap switch test system after a system fault occurs.

[0116] The power switch is in communication connection with the control unit. On the one hand, the control unit can control the power switch to perform closing or opening operations, without the need for manual closing or turning off of the power switch, thereby improving safety performance. On the other hand, the control unit obtains the running data of the power switch through the communication connection mode of the temperature sensor, voltmeter and other information acquisition devices, analyzes the running state of the power switch, and can thus give early warning or prompt for the fault risk of the power switch. When a fault with a relatively high risk (for example, a short circuit fault) occurs during the tap switch test, the power switch can be actively turned off.

[0117] According to the power supply capacity requirement of the tap switch test system in the embodiment of the present application, a power transformer with appropriate capacity is selected, and the ratio of the selected power transformer is designed to meet the AC side input requirement of the power rectifier. The power transformer converts the AC power of the AC power grid into AC power that meets the AC side input requirement of the power rectifier, and inputs it to the power rectifier. The power rectifier converts the AC power into DC power and delivers it to the inverter unit through the DC bus.

[0118] In the embodiment of the present application, the power rectifier is a common modern rectifying device. Based on the internal various types of full- and half-controlled devices and circuit topology design, the power rectifier has functions such as active and reactive power independent control, power factor automatic adjustment, voltage source and current source, etc. The power rectifier can select and execute corresponding functions according to the running needs of the tap switch test system, and also has self-protection functions such as overvoltage, overcurrent and overtemperature.

[0119] In the embodiments of the present application, the control unit is in communication connection with the power rectifier. Based on the various types of full-controlled and half-controlled devices, circuit topology design inside the power rectifier, and the communication connection between the control unit and the power rectifier, on the one hand, the control unit can realize the function switching control and switching control of the power rectifier; on the other hand, through the information collection devices such as voltmeter, ammeter, temperature sensor, the control unit can obtain the corresponding operation data based on the communication connection mode and analyze, and then judge whether the power rectifier has operation risk, and control the power rectifier to execute the corresponding self-protection function when the operation risk exists.

[0120] Since the power rectifier can independently control the active power and the reactive power exchanged with the alternating current grid, the power rectifier can actively improve the power factor of the access point of the alternating current grid while drawing the energy of the alternating current grid. And based on the pulse width modulation (PWM) and current tracking, the power rectifier can actively generate a relatively smooth sinusoidal current to realize the harmonic compensation of the grid, thereby improving the power quality.

[0121] In the conventional operation condition of the tap changer test system, that is, the tap changer test system is used for tap changer test, the power rectifier executes the voltage source function to provide a relatively stable direct current power supply for the test. Since the voltage source function of the power rectifier is realized based on current closed-loop control, the power rectifier has current limiting capability when executing the voltage source function, which can avoid overcurrent damage to the test system.

[0122] When the tap changer test system is not used for tap changer test, but only for charging the energy storage system, the power rectifier can execute the current source function, which has safe, uniform speed and controllable charging effect at this time.

[0123] The present application does not limit the circuit topology structure of the power rectifier. For example, the circuit can be a two-level topology structure, a three-level topology structure or a modular multi-level topology structure, etc.

[0124] In the embodiments of the present application, the voltage meter, the ammeter, the temperature sensor and other data collection devices are used to collect the operation data of the power transformer, such as voltage, current, active power, reactive power, electric energy and oil temperature.

[0125] In the embodiments of the present application, the power transformer is in communication connection with the control unit, the control unit obtains and analyzes the operation data of the power transformer, realizes the monitoring of the operation state of the power transformer, and can give a warning or a prompt when the power transformer has operation risk.

[0126] In the embodiment of the present application, the energy storage unit includes a bidirectional DC-DC converter and an energy storage device, and the control unit is in communication connection with the bidirectional DC-DC converter and the energy storage device.

[0127] The bidirectional DC-DC converter is connected to the DC bus on one side and connected to the energy storage device on the other side. The control unit acquires at least the following parameters through communication connection:

[0128] The voltage, current and other electrical data of the DC output end of the power rectifier, i.e., the voltage, current and other electrical data of the DC bus;

[0129] The charge and discharge current and other electrical data of the bidirectional DC-DC converter;

[0130] The temperature, charge and discharge voltage, charge and discharge current and other electrical data of the energy storage device.

[0131] Based on the acquired electrical data of the DC bus and the requirement of stabilizing the DC bus voltage, the control unit sends a control signal to the fully controlled or semi-controlled switching device in the bidirectional DC-DC converter to switch the bidirectional DC-DC converter to work in a charging mode or a discharging mode, and to adjust the charge and discharge current of the bidirectional DC-DC converter in real time, so as to finally realize the charge and discharge control of the energy storage unit.

[0132] Specifically, both sides of the bidirectional DC-DC converter can be used as an input end or an output end of electrical energy. When the bidirectional DC-DC converter works in the charging mode, the side connected to the DC bus is used as the input end of electrical energy, and the other side is used as the output end. At this time, the electrical energy of the DC bus is transmitted to the energy storage device through the bidirectional DC-DC converter, so as to realize the charging of the energy storage device and reduce the DC bus voltage. When the bidirectional DC-DC converter works in the discharging mode, the side connected to the DC bus is used as the output end of electrical energy, and the other side is used as the input end. At this time, the electrical energy of the energy storage device is transmitted to the DC bus through the bidirectional DC-DC converter, so as to increase the bus voltage.

[0133] In the embodiment of the present application, the circuit topology of the bidirectional DC-DC converter is not limited. For example, the circuit topology of the bidirectional DC-DC converter can be an isolated type or a non-isolated type.

[0134] In the embodiment of the present application, the energy storage device can be an electrochemical energy storage device, a super capacitor or a flywheel energy storage device.

[0135] In the embodiment of the present application, the bidirectional DC-DC converter and the energy storage device cooperate to make the energy storage unit operate in a current source mode in a normal manner, and the charge and discharge current of the energy storage unit can be adjusted in real time by the control unit.

[0136] Based on the communication connection of the control unit with the bidirectional DC-DC converter and the energy storage device, the energy storage unit also has the functions of overvoltage protection, overcurrent protection, overtemperature protection and the like. When the energy storage device is an electrochemical energy storage device, it also has the functions of monitoring and protection of the state of charge (SOC) and the state of health (SOH) of the battery.

[0137] The communication connection mode in the embodiments of the present application is not limited. The communication connection mode can be various, for example, the communication connection mode can be a wireless communication connection mode such as Wi-Fi or Bluetooth, or a wired communication connection mode such as optical fiber or power line.

[0138] The tap switch test method of the embodiments of the present application will be described in detail below. Figure 1 、 Figure 2 and Figure 4 .

[0139] The tap switch test method of the embodiments of the present application is shown in combination with Figure 1 and Figure 2 , and reference is made to Figure 4 , Figure 4 .

[0140] In the embodiments of the present application, the tap switch test method is applied to a tap switch test system as shown in Figure 1 . The tap switch test system includes an inverter unit, a rectifier unit, a control unit and a tap switch. The DC side of the inverter unit is connected with an external power supply and connected with the DC side of the rectifier unit. The AC side of the inverter unit includes a first output end, a second output end and a third output end. The tap switch is connected in series on the power transmission path between the first output end, the second output end and the AC side of the rectifier unit. The tap switch includes a plurality of switching circuits, and the third output end is directly connected with the AC side of the rectifier unit.

[0141] As shown in Figure 4 , the tap switch test method in the embodiments of the present application can include steps S100-300:

[0142] Step S100: The control unit determines the current test environment to be provided, and based on the test environment, controls the inverter unit to adjust the test electrical signal output by the inverter unit in real time, so as to provide different test environments for the tap switch;

[0143] Step S200: The control unit controls the rectifier unit to adjust the input parameters of the AC side of the rectifier unit, so that the rectifier unit adapts to the test electrical signal output by the inverter unit and feeds back the electrical energy to the inverter unit;

[0144] Step S300: The control unit obtains test data of the tapping switch under the test electrical signal based on the test environment and in response to the tapping switch being in the static operation state or the dynamic switching state, and analyzes the reliability of the tapping switch based on the test data; the test data includes all test data of the dynamic switching process of the plurality of switching circuits.

[0145] In the embodiments of the present application, the test environment in step S100 includes a static test environment and a dynamic test environment.

[0146] Specifically, the tapping switch is tested when it is in the static state, and the required test environment at this time is the static test environment. Under the static test environment, the tapping switch can be tested for contact resistance, insulation resistance, AC voltage resistance, and other tests to verify the electrical and mechanical properties of the tapping switch in the static state and confirm the reliability of the tapping switch in the static state.

[0147] Different static test projects require different static test environments, i.e., different test electrical signals. The control unit controls the inverter unit to output test electrical signals that meet the requirements of the test project based on the static test environment required by the specific test project.

[0148] In combination with FIG. 2, Figure 2 As shown in FIG. 2, when the test environment is the static test environment, in response to the tapping switch being in the static operation state, i.e., in response to any of the first to sixth switching circuits being stably turned on and having current flowing therethrough, the control unit controls the inverter unit to adjust the output test electrical signal based on the static test environment.

[0149] Specifically, the tapping switch is tested when it is in the dynamic switching state, and the required test environment at this time is the dynamic test environment. Under the dynamic test environment, the tapping switch can be tested for switching timing, dynamic resistance, action sequence, contact switching, and full working condition operation, etc. to verify the electrical and mechanical properties of the tapping switch in the dynamic switching process and confirm the reliability of the tapping switch in the dynamic switching process.

[0150] Different dynamic test projects require different dynamic test environments, i.e., different test electrical signals. The control unit controls the inverter unit to output test electrical signals that meet the requirements of the test project based on the dynamic test environment required by the specific test project.

[0151] In combination with FIG. 3, Figure 2 As shown in FIG. 3, when the test environment is the dynamic test environment, in response to the tapping switch being in the dynamic switching state, i.e., in response to the first to sixth switching circuits being turned on in the specified order in the dynamic switching process, the control unit controls the inverter unit to continuously adjust the output test electrical signal in real time based on the dynamic test environment.

[0152] By real-time adjustment of the test electrical signal, the test electrical signal can sufficiently simulate the full working condition operation environment of the tapping switch, and thus full working condition static and dynamic switching tests of the tapping switch can be completed, and the reliability of the tapping switch in the actual application scenario and the adaptability of the tapping switch in the full working condition complex power grid form can be fully verified.

[0153] It can be understood that when it is necessary to verify the adaptability of the tapping switch in the full working condition complex power grid form, full working condition operation tests need to be performed, at this time, the control unit controls the inverter unit to adjust the test electrical signal in real time to simulate the full working condition complex power grid form, including but not limited to changing the harmonic amplitude and / or harmonic content of the test electrical signal to simulate the harmonic change in the power grid, changing the voltage amplitude to simulate the voltage amplitude mutation in the power grid, and changing the current amplitude to simulate the current impact in the power grid, so as to realize all-around simulation of the full working condition complex power grid form. At this time, the test environment can be a static test environment or a dynamic test environment, which depends on whether the tapping switch is in a static operation state or a dynamic switching state during the test.

[0154] In the embodiment of the application, the control unit controls the inverter unit to adjust the output test electrical signal, including adjusting at least one of the following parameters of the test electrical signal: fundamental wave voltage amplitude, fundamental wave current amplitude, fundamental wave frequency and harmonic component, wherein the harmonic component includes harmonic amplitude and harmonic content. By adjusting the above parameters, test electrical signals meeting the requirements of different test items can be output, and thus the test environment requirements of different tests can be met.

[0155] The tapping switch test method provided in the embodiment of the application controls the inverter unit to adjust the test electrical signal through the control unit, so as to sufficiently simulate the test environment required by the tapping switch for full working condition dynamic and static tests, and thus full working condition dynamic and static tests of the tapping switch are realized, so as to fully verify the electrical performance, mechanical performance, aging life, fault risk and the like of the tapping switch.

[0156] The following will be described in combination with Figure 5 The process in which the control unit analyzes the reliability of the tapping switch based on the test data in step S300 will be described in detail.

[0157] Figure 5 The process in which the control unit analyzes the reliability of the tapping switch based on the test data in step S300 is shown, and the process includes:

[0158] Step S310: The control unit analyzes the electrical performance, mechanical performance, electrical life and mechanical life of the tapping switch based on the test data.

[0159] Step S320: The control unit determines whether there is a fault risk.

[0160] Step S330: If there is no risk of failure in the tap changer, the control unit generates a test report.

[0161] In this step, staff obtain test data and analysis results of the tap changer through the test report, thereby obtaining various information such as the tap changer's electrical performance, mechanical performance, electrical life, mechanical life, and failure risk, and completing the reliability assessment of the tap changer.

[0162] Step S340: If there is a risk of failure in the tap changer, the control unit generates a test report and issues a fault warning.

[0163] In this step, staff can learn about fault risks through test reports and fault warnings, thus enabling them to promptly troubleshoot tap changers and prevent tap changer failures from damaging the test system and the power grid.

[0164] like Figure 5 As shown, in some other embodiments, step S340 further includes the following steps:

[0165] If there is a risk of failure in the tap changer, the control unit builds a fault risk prediction model based on the correspondence between test data and fault risks. The fault risk prediction model is used to predict the fault risk of the tap changer under real operating conditions.

[0166] In this step, since the test electrical signal can be adjusted in real time, it provides a full-condition operating environment simulation for tap changer testing. Therefore, the correspondence between test data and fault risk is close to the actual operating conditions of the tap changer. Based on this, the fault risk prediction model has a more accurate fault risk prediction effect.

[0167] In summary, the tap changer testing system and method provided in this application connect the tap changer under test between the output terminal of the inverter unit and the input terminal of the rectifier power supply, and connect the output terminal of the rectifier power supply to the input terminal of the inverter unit, forming a power circulating circuit for testing the tap changer. The control unit dynamically adjusts the test signal output by the inverter unit. Through power circulation, the capacity requirement of the AC power grid during testing is effectively reduced, solving the problem of power limitation in large-capacity on-load tap changer testing due to limited grid capacity. Furthermore, the dynamic adjustment of the test signal fully simulates the full-condition operating environment of the tap changer, enabling dynamic and static testing of the tap changer under all operating conditions. This fully verifies the adaptability and reliability of the tap changer in complex field operating environments. Moreover, the correlation model built based on the relationship between test data and corresponding fault risks can be used to predict the fault risks of the tap changer in actual operating environments, improving the current problem of lagging tap changer condition assessment and enabling predictive maintenance of the tap changer.

[0168] In some embodiments, the embodiments of the present application further provide a computer readable medium, at least one instruction or at least one program is stored on the computer readable medium, when the at least one instruction or at least one program is loaded and executed by the processor, the computer executes the tapping switch test method described in the above embodiments.

[0169] In some embodiments, the embodiments of the present application further provide an electronic device, the electronic device includes a processor and a memory, at least one instruction or at least one program is stored in the memory, when the at least one instruction or at least one program is loaded and executed by the processor, the electronic device executes the tapping switch test method described in the above embodiments.

[0170] In some embodiments, the embodiments of the present application further provide a computer program product, comprising: computer instructions, when the computer instructions run on the electronic device, the electronic device realizes the tapping switch test method described in the above embodiments.

[0171] Now referring to Figure 6 , a block diagram of a system on chip (Soc) 1300 according to an embodiment of the present application is shown. In Figure 6 , similar components have the same reference numbers. In addition, the dashed line block is an optional feature of the more advanced system on chip. In Figure 6 , the system on chip 1300 includes: an interconnection unit 1350 coupled to an application processor 1310; a system agent unit 1380; a bus controller unit 1390; an integrated memory controller unit 1340; one or more sets of co-processors 1320, which can include integrated graphics logic, an image processor, an audio processor and a video processor; a static random access memory (SRAM) unit 1330; a direct memory access (DMA) unit 1360. In one embodiment, the co-processor 1320 includes a special-purpose processor, such as a network or communication processor, a compression engine, a graphics processor (GPU), a high-throughput integrated many integrated cores (MIC) processor, or an embedded processor, etc.

[0172] The static random access memory (SRAM) unit 1330 can include one or more computer-readable media for storing data and / or instructions. The computer-readable storage media can store instructions, in particular, a transient or a permanent copy of the instructions. The instructions can include causing the Soc 1300 to perform the tap switch testing method according to the above-described embodiments, in particular, the method of the above-described embodiments, which will not be repeated here.

[0173] Embodiments of the mechanisms disclosed herein can be implemented in hardware, software, firmware, or any combination thereof. Embodiments of the application can be implemented as computer program products or program code that can be executed on programmable systems including at least one processor, a storage system (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device.

[0174] Program code can be applied to input instructions to perform the functions described herein and generate output information. The output information can be applied to one or more output devices, in known fashion. For purposes of this application, a processing system includes any system that has a processor, such as, for example; a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), or a microprocessor.

[0175] The program code can be implemented in a high level procedural or object oriented programming language to communicate with a processing system. The program code can be implemented in assembly or machine language, if desired. In fact, the mechanisms described herein are not limited in scope to any particular programming language. In any case, the language can be a compiled or interpreted language.

[0176] In some cases, the disclosed embodiments can be implemented in hardware, firmware, software, or any combination thereof. The disclosed embodiments can also be implemented as instructions carried by or stored on one or more transitory or non-transitory machine- readable (e.g., computer-readable) media, which can be read and executed by one or more processors. For example, the instructions can be distributed over the network or by other computer readable media. Thus, a machine-readable medium can include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer), including without limitation, a floppy disk, an optical disc, an optical compact disc read-only memory (CD-ROM), a magneto-optical disk, read-only memory (ROM), random access memory (RAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic or optical cards, flash memory, or a tangible, machine-readable storage used in the transmission of information over the Internet via electrical, optical, acoustical or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.). Accordingly, the machine-readable media includes any type of media understandable by a machine (e.g., a computer) to store or transmit information in a form readable by that machine.

[0177] In the drawings, some of the structural or methodological features can be shown in particular arrangements and / or orders. It should be understood that such specific arrangements and / or orders can not be required. Instead, these features can be arranged in a different manner and / or order in some embodiments. Additionally, inclusion of a structural or methodological feature in a particular figure is not meant to imply that such feature is required in all embodiments, and these features can be excluded or combined with other features in some embodiments.

[0178] It should be noted that each unit / module mentioned in each device embodiment of the present application is a logical unit / module, and in physical, one logical unit / module can be a physical unit / module, or a part of a physical unit / module, or can be implemented by a combination of multiple physical unit / modules, and the physical implementation of the logical unit / module is not the most important thing, and the combination of the functions implemented by these logical units / modules is the key to solving the technical problems proposed in the present application. In addition, in order to highlight the innovative part of the present application, the above-mentioned device embodiments of the present application do not introduce the units / modules that are not closely related to solving the technical problems proposed in the present application, which does not mean that the above-mentioned device embodiments do not have other units / modules.

[0179] It should be noted that in the examples and descriptions of the present application, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including one" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0180] Although the present application has been illustrated and described with reference to certain preferred embodiments thereof, it should be understood by those skilled in the art that various changes in form and details can be made therein without departing from the spirit and scope of the present application.

Claims

1. A tap changer testing system, characterized in that, include: A tap changer includes two input terminals and one output terminal. The two input terminals are electrically connected, and multiple switching circuits are provided between the two input terminals and the output terminal. The multiple switching circuits are connected in parallel. An inverter unit is used to convert direct current into alternating current output. The AC side of the inverter unit includes a first output terminal, a second output terminal, and a third output terminal. The first output terminal and the second output terminal are connected to the two switch input terminals one by one. The AC voltages output by the first output terminal and the second output terminal have the same phase but different amplitudes. The phase difference between the AC voltages output by the first output terminal, the second output terminal, and the AC voltage output by the third output terminal is 120°. A rectifier unit is used to convert alternating current (AC) into direct current (DC) output. The AC side of the rectifier unit includes a first input terminal and a second input terminal. The second input terminal is connected to the third output terminal, and the first input terminal is connected to the switch output terminal. The DC side of the rectifier unit is connected to the DC side of the inverter unit. The control unit, which is communicatively connected to the inverter unit, is used to control the inverter unit to dynamically adjust the test electrical signal output by the inverter unit based on the test environment to be provided, and to acquire the test data of the tap changer under the test electrical signal, and to analyze the reliability of the tap changer under all operating conditions based on the test data; the test data includes all test data of the dynamic switching process of multiple switching circuits.

2. The tap changer testing system according to claim 1, characterized in that, The parameters of the test electrical signal include at least one of the following: fundamental voltage amplitude, fundamental current amplitude, harmonic components, and fundamental frequency.

3. The tap changer testing system according to claim 1, characterized in that, The control unit is communicatively connected to the rectifier unit. The control unit is used to control the rectifier unit to adjust the AC side input parameters of the rectifier unit based on the test electrical signal, so that the rectifier unit adapts to the test electrical signal output by the inverter unit and feeds electrical energy back to the inverter unit.

4. The tap changer testing system according to claim 1, characterized in that, It also includes a power supply unit, which is used to connect to an external AC power grid and output DC power. The DC output terminal of the power supply unit is connected to a DC bus, and the DC bus is connected to the DC side of the inverter unit.

5. The tap changer testing system according to claim 4, characterized in that, The power supply access unit includes: A grid connection unit includes an AC input terminal and a DC output terminal. The grid connection unit is used to convert AC power into DC power and output it. The AC input terminal is connected to the AC power grid, and the DC output terminal is connected to the DC bus. An energy storage unit is connected to the DC bus and is used to charge and discharge relative to the DC bus to clamp the voltage of the DC bus at a preset voltage value.

6. The tap changer testing system according to claim 5, characterized in that, The energy storage unit includes a bidirectional DC-DC converter and an energy storage device. One side of the bidirectional DC-DC converter is connected to the DC bus, and the other side of the bidirectional DC-DC converter is connected to the energy storage device.

7. The tap changer testing system according to claim 6, characterized in that, The control unit is communicatively connected to the bidirectional DC-DC converter and is used to control the bidirectional DC-DC converter to operate in charging mode or discharging mode.

8. A method for testing tap changers, characterized in that, An application is made in a tap changer testing system, the tap changer testing system including an inverter unit, a rectifier unit, a control unit, and a tap changer. The DC side of the inverter unit is connected to an external power supply and to the DC side of the rectifier unit. The AC side of the inverter unit includes a first output terminal, a second output terminal, and a third output terminal. The tap changer is connected in series in the power transmission path between the first and second output terminals and the AC side of the rectifier unit. The AC voltages output by the first and second output terminals have the same phase but different amplitudes. The phase difference between the AC voltages output by the first and second output terminals and the AC voltage output by the third output terminal is 120°. The tap changer includes multiple switching circuits. The third output terminal is connected to the AC side of the rectifier unit. The method includes: The control unit determines the current test environment to be provided, and based on the test environment, controls the inverter unit to adjust the test electrical signal output to the tap switch in real time, so as to provide different test environments for the tap switch; The control unit controls the rectifier unit to adjust the AC side input parameters of the rectifier unit so that the rectifier unit adapts to the test electrical signal output by the inverter unit and feeds electrical energy back to the inverter unit; The control unit, based on the test environment and in response to whether the tap switch is in a steady-state operation or a dynamic switching state, acquires test data of the tap switch under the test electrical signal, and analyzes the reliability of the tap switch based on the test data; the test data includes all test data of the dynamic switching process of multiple switching circuits.

9. The tap changer testing method according to claim 8, characterized in that, The test data includes: Electrical data, including voltage, current, and frequency data of multiple switching circuits, is used to evaluate the electrical and mechanical performance of the tap changer; The sensing data includes the vibration signal and switching frequency of the tap changer, and the sensing data is used to evaluate the mechanical performance of the tap changer.

10. The tap changer testing method according to claim 8, characterized in that, Based on the test environment, the control unit controls the inverter unit to adjust the test electrical signal output to the tap changer in real time, including: When the test environment is a static test environment, in response to the tap changer being in a static operating state, the control unit controls the inverter unit to adjust the output test electrical signal based on the static test environment; And / or, when the test environment is a dynamic test environment, in response to the tap changer being in a dynamic switching state, the control unit controls the inverter unit to continuously adjust the output test electrical signal in real time based on the dynamic test environment.

11. The tap changer testing method according to claim 8, characterized in that, The reliability analysis of the tap changer based on the test data includes: Based on the test data, the control unit analyzes the electrical performance, mechanical performance, electrical life, and mechanical life of the tap changer. The control unit determines whether the tap changer has a risk of failure. If the tap changer does not pose the aforementioned fault risk, the control unit generates a test report; In the event of the aforementioned fault risk in the tap changer, the control unit generates the test report and issues a fault warning.

12. The tap changer testing method according to claim 11, characterized in that, Also includes: If the tap changer has the aforementioned fault risk, the control unit builds a fault risk prediction model based on the correspondence between the test data and the fault risk. The fault risk prediction model is used to predict the fault risk of the tap changer under actual operating conditions.

13. An electronic device, characterized in that, The electronic device includes a processor and a memory, the memory storing at least one instruction or at least one program, the at least one instruction or the at least one program being loaded and executed by the processor to implement the tap changer test method as described in any one of claims 8 to 12.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores at least one instruction or at least one program, which is loaded and executed by a processor to implement the tap changer test method as described in any one of claims 8 to 12.

15. A computer program product, characterized in that, include: Computer instructions, when executed on an electronic device, cause the electronic device to perform the tap changer test method according to any one of claims 8 to 12.

Images