A power distribution network insulation resistance testing device and a testing method thereof

Abstract

The embodiment of the application discloses a kind of distribution network insulation resistance test device and its testing method.The distribution network insulation resistance test device includes: multiple output channels;Test terminal;Channel switching module, channel switching module includes static contact, moving contact and driving mechanism, moving contact is connected with output channel, and driving mechanism is used to drive moving contact to move;Control module is used to obtain the initial position of the moving contact corresponding to different output channels, determines the target position of the moving contact in the corresponding output channel according to test demand, and according to the initial position and target position, the corresponding driving mechanism is controlled to extend or retract movement along the linear direction, so that the moving contact is electrically connected with the static contact corresponding to the target position.The application adjusts the connection relationship between multiple output channels and the distribution network to be measured, realizes the automatic test of multiple insulation resistances, introduces automatic discharge function, protects equipment and measured object, simplifies operation process, and improves test efficiency and test safety.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power testing, in particular to a power distribution network insulation resistance testing device and a testing method thereof. BACKGROUND

[0002] The safe operation of the power distribution network is crucial to the stability of the power system. Insulation resistance testing is an important means of evaluating the insulation performance of the power distribution network, which is used to detect potential insulation faults and ensure the safe operation of the power system.

[0003] During the insulation resistance testing of the power distribution network, for the insulation resistance testing of the three-phase line, not only the insulation resistance values between the phases need to be measured, but also the insulation resistance values between each phase and the ground need to be measured. For the operation and maintenance testing of the transformer, the insulation resistance between the windings and between the windings and the ground also needs to be measured. The traditional insulation resistance tester can only measure one set of data at a time in actual operation. Each measurement requires multiple operations such as wiring, starting measurement, recording data, discharging, and removing the lead, which is tedious, time-consuming, and low in efficiency.

[0004] Although the existing digital insulation tester has improved the testing efficiency to some extent, it still needs to test the resistance of each circuit one by one for multiple insulation resistance tests, and the data is recorded manually. After each set of testing is completed, the circuits are discharged manually, which is time-consuming and prone to errors, and cannot meet the needs of intelligent operation and maintenance. SUMMARY

[0005] The present application provides a power distribution network insulation resistance testing device and a testing method thereof. The device automatically completes the insulation resistance testing task by adjusting the connection relationship between multiple output channels and the power distribution network to be tested, increases the safety of the insulation tester, and improves the testing efficiency of the insulation tester.

[0006] In a first aspect, the present application provides a power distribution network insulation resistance testing device, comprising: a plurality of output channels, the output channel being used to connect the power distribution network to be tested; a test terminal, at least comprising: a high-voltage output positive terminal, a high-voltage output negative terminal, and a discharge terminal; a channel switching module, which is set one-to-one corresponding to the output channel, the channel switching module comprising a static contact, a moving contact, and a driving mechanism, the static contact being connected one-to-one to the test terminal, the moving contact being connected to the output channel, and the driving mechanism being used to drive the moving contact to move in a straight line direction; a control module, connected to the control end of the driving mechanism, used to obtain the initial position of the moving contact corresponding to different output channels, determine the target position of the moving contact in the corresponding output channel according to the testing requirements, and control the corresponding driving mechanism to extend or retract in a straight line direction according to the initial position and the target position, so that the moving contact is electrically connected to the static contact corresponding to the target position.

[0007] Optionally, the fixed contact includes a first conductive part and a first insulating sheath sleeved on the periphery of the first conductive part; the movable contact includes a second conductive part and a second insulating sheath sleeved on the periphery of the second conductive part; when the movable contact is connected with the fixed contact, the first conductive part and the second conductive part are in elastic interference contact; when the movable contact is not connected with the fixed contact, the minimum interval distance between the first conductive part and the second conductive part is greater than a preset air insulation interval; wherein the preset air insulation interval is calculated based on the insulation resistance of the power distribution network to be tested.

[0008] Optionally, the first insulating sheath and the second insulating sheath are made of an insulating material; the thickness of the insulating material is calculated based on the insulation resistance of the power distribution network to be tested.

[0009] Optionally, the first conductive part includes two connecting pieces with tapered sections; the second conductive part includes two trapezoidal connecting pieces, and the trapezoidal upper bases of the trapezoidal connecting pieces are oppositely arranged.

[0010] Optionally, the driving mechanism includes an electric telescopic rod for fixing the movable contact, a push rod control circuit for controlling the electric telescopic rod to extend when receiving a first control signal output by the control module, and for controlling the electric telescopic rod to retract when receiving a second control signal output by the control module.

[0011] Optionally, the push rod control circuit includes a driving motor, a forward rotation driving branch, and a reverse rotation driving branch; the driving motor is meshed and connected with the electric telescopic rod; the forward rotation driving branch is configured to apply a forward voltage to the driving motor to make the driving motor rotate forward and drive the electric telescopic rod to extend when receiving the first control signal; the reverse rotation driving branch is configured to apply a reverse voltage to the driving motor to make the driving motor rotate reverse and drive the electric telescopic rod to retract when receiving the second control signal.

[0012] Optionally, the discharge end includes a ground end and / or a common end; the ground end is provided with a discharge resistor and a discharge switch connected in parallel with the fixed contact; the control module is further configured to obtain a voltage sampling value of the output channel, and control the discharge switch to be closed when the voltage sampling value is within a preset safety range.

[0013] Optionally, the power distribution network insulation resistance testing device provided by any one of the embodiments of the present application can further include a channel state indication module connected with the control module, configured to indicate the connection mode of each output channel; the connection mode includes any one of the following: connecting the high-voltage output positive end, connecting the high-voltage output negative end, or connecting the discharge end.

[0014] Optionally, the control module applied to any one of the power distribution network insulation resistance testing devices provided by the embodiments of the present application can be configured to: obtain a reference time required for the moving contact to move between two adjacent stationary contacts, and calculate the working time length of the driving mechanism in the corresponding output channel according to the reference time and the initial position and the target position in the different output channels, and configure the target position as the position corresponding to the discharge end when the driving time of the driving mechanism reaches the working time length.

[0015] In a second aspect, the embodiments of the present application further provide a power distribution network insulation resistance testing method, which can be implemented by any one of the power distribution network insulation resistance testing devices provided by the embodiments of the present application. The power distribution network insulation resistance testing device comprises a plurality of output channels and test terminals, the output channels are connected with moving contacts, and the test terminals are connected with stationary contacts. The method comprises: obtaining the initial positions of the moving contacts corresponding to different output channels; determining the target positions of the moving contacts in the corresponding output channels according to testing requirements; and controlling the moving contacts to move according to the initial positions and the target positions, so that the moving contacts are electrically connected with the stationary contacts corresponding to the target positions.

[0016] The power distribution network insulation resistance testing device and the testing method provided by the embodiments of the present application have the following advantages. The testing device is provided with a plurality of output channels, test terminals, a channel switching module and a control module. The connection relationship between the plurality of output channels and the power distribution network to be tested is adjusted by the channel switching module, and the pass testing, discharging and resetting processes are sequentially completed. The tedious sequential measurement, discharging and circuit switching process in the existing insulation testing work is optimized, the automatic testing of a plurality of insulation resistances is realized, the testing efficiency is improved, the error rate of manual operation is reduced, and the safety hidden danger in the insulation testing process is reduced. The measured loop is automatically discharged after the testing is completed, which protects the testing equipment and the measured loop, further simplifies the operation process, and significantly improves the safety and reliability of the testing. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 FIG. 1 is a structural schematic diagram of a power distribution network insulation resistance testing device provided by an embodiment of the present application;

[0018] Figure 2 FIG. 2 is a structural schematic diagram of a channel switching module provided by an embodiment of the present application;

[0019] Figure 3 FIG. 3 is a circuit principle diagram of a push rod control circuit provided by an embodiment of the present application;

[0020] Figure 4 FIG. 4 is a flowchart of a power distribution network insulation resistance testing method provided by an embodiment of the present application;

[0021] Figure 5Another flow chart of the method for testing insulation resistance of a power distribution network according to an embodiment of the present application is shown in FIG. 6.

[0022] Figure 6 Another flow chart of the method for testing insulation resistance of a power distribution network according to an embodiment of the present application is shown in FIG. 6. DETAILED DESCRIPTION

[0023] The present application will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are intended to be merely illustrative of the present application and not in limitation thereof. It should also be noted that, for the purpose of convenience, only the parts related to the present application are shown in the drawings rather than all the parts.

[0024] The terms used in the embodiments of the present application are merely for the purpose of describing specific embodiments and are not intended to limit the present application. It should be noted that the terms "upper", "lower", "left", "right" described in the embodiments of the present application are described in the angle shown in the drawings and should not be understood as limiting the embodiments of the present application. In addition, it should be understood in the context that when referring to one element being formed "on" or "under" another element, it can be directly formed "on" or "under" another element, or indirectly formed "on" or "under" another element through an intermediate element. The terms "first", "second" are merely for the purpose of description and do not represent any order, quantity or importance, but are used to distinguish different components. For those skilled in the art, the specific meanings of the above terms in the present application should be understood according to the specific circumstances.

[0025] The term "comprising" and its variants used in the present application are open and inclusive, i.e. "including but not limited to". The term "based on" is "at least partially based on". The term "one embodiment" means "at least one embodiment".

[0026] It should be noted that the "first", "second" concepts mentioned in the present application are merely used to distinguish the corresponding content and are not used to limit the order or mutual dependency.

[0027] It should be noted that the modification of "one", "multiple" mentioned in the present application is illustrative rather than limiting, and those skilled in the art should understand that unless otherwise explicitly indicated in the context, it should be understood as "one or more".

[0028] Figure 1 A structural schematic diagram of a power distribution network insulation resistance testing device according to an embodiment of the present application is shown in FIG. 1. Figure 1The power distribution network insulation resistance testing device 100 provided by the embodiment of the application comprises: a plurality of output channels 11, which are used for connecting to the power distribution network to be tested; a testing terminal 20, which at least comprises a high-voltage output positive terminal 21, a high-voltage output negative terminal 22 and a discharge terminal 23; a channel switching module 30, which is arranged in one-to-one correspondence with the output channels 11, and comprises a static contact 32, a dynamic contact 31 and a driving mechanism 33, the static contact 32 is connected to the testing terminal 20 in one-to-one correspondence, the dynamic contact 31 is connected to the output channel 11, and the driving mechanism 33 is used to drive the dynamic contact 31 to move in a straight line direction; and a control module 40, which is connected to the control end of the driving mechanism 33, is used to obtain the initial position of the dynamic contact 31 corresponding to the different output channels 11, determine the target position of the dynamic contact 31 in the corresponding output channel 11 according to the testing requirement, and control the corresponding driving mechanism 33 to extend or retract in a straight line direction according to the initial position and the target position, so that the dynamic contact 31 is electrically connected to the static contact 32 corresponding to the target position.

[0029] The power distribution network to be tested can be understood as part of the power system or a component that needs to be tested for insulation resistance. For example, the power distribution network to be tested includes but is not limited to: single-phase cable, multi-phase (for example, two-phase or three-phase) cable, transformer, switching element; the output channel 11 can be understood as an interface in the power distribution network insulation resistance testing device 100 for connecting the power distribution network to be tested; the testing terminal 20 can be understood as a terminal in the power distribution network insulation resistance testing device 100 for providing a test voltage or a discharge circuit to the power distribution network to be tested. The testing terminal 20 at least comprises a high-voltage output positive terminal 21, a high-voltage output negative terminal 22 and a discharge terminal 23; the high-voltage output positive terminal 21 is used to provide a positive test voltage to the power distribution network to be tested; the high-voltage output negative terminal 22 is used to provide a negative test voltage to the power distribution network to be tested; the discharge terminal 23 can be understood as a special testing terminal in the power distribution network insulation resistance testing device 100, which is used to provide a discharge circuit to the power distribution network to be tested after the test is completed, so as to release the residual charge in the power distribution network to be tested. The channel switching module 30 can be understood as a module for automatically switching between the connection relationship of the driving output channel 11 and different testing terminals, so as to test different power distribution networks to be tested in turn; the static contact 32 can be understood as a fixed terminal connected to the testing terminal 20 in one-to-one correspondence. The dynamic contact 31 can be understood as a terminal that moves between the static contacts 32 through the movement of the driving mechanism 33, so as to be electrically connected to different static contacts 32. In this embodiment, the testing terminal 20 outputs a test signal through the static contact 32, and after the dynamic contact 31 is electrically connected to the static contact 32, the test signal is transmitted to the output channel 11 connected to the dynamic contact 31 through the dynamic contact 31.

[0030] In the embodiment, the connection relationship between the moving contact 31 and the fixed contact 32 is established based on test requirements. The test requirements include, but are not limited to, any one of the following: phase-to-phase insulation resistance test requirement, phase-to-ground insulation resistance test requirement, transformer winding-to-winding insulation resistance test requirement, transformer winding-to-ground insulation resistance test requirement, and post-test discharge requirement.

[0031] Specifically, in the present application, the power distribution network insulation resistance test device 100 has a plurality of output channels 11, so as to be able to simultaneously or sequentially connect a plurality of power distribution networks to be tested for testing. The output channels 11 are one-to-one corresponding to the channel switching module 30, ensuring that each power distribution network to be tested can be tested through the corresponding output channel 11. The driving mechanism 33 is used to control the movement of the moving contact 31 in a linear direction. The linear direction is the arrangement direction of the fixed contact 32. The control module 40 is used to obtain the initial position of the moving contact 31 corresponding to different output channels 11, and determine the target position according to the test requirements. Then, the control module 40 generates a driving task according to the initial position and the target position, controls the driving mechanism 33 corresponding to the output channel 11 to extend or retract in the linear direction according to the driving task, so as to move the moving contact 31 on the driving mechanism 33 to the target position and electrically connect with the fixed contact 32 corresponding to the target position. For example, if the initial position of the moving contact 31 is that the moving contact 31 is connected with the fixed contact 32 corresponding to the discharge end 23, and the target position corresponding to the test requirement is that the moving contact 31 is connected with the fixed contact 32 corresponding to the high-voltage output positive end 21, then the control module 40 determines the moving direction and target distance of the moving contact 31 according to the interval between the fixed contact 32 corresponding to the discharge end 23 and the fixed contact 32 corresponding to the high-voltage output positive end 21, and controls the driving mechanism 33 to extend or retract in the linear direction by the target distance based on the moving direction and the target distance. In addition, the control module 40 can also have other functions, such as automatic discharge after testing. After the test is completed, the target position corresponding to the test requirement is determined as that the moving contact 31 is connected with the fixed contact 32 corresponding to the discharge end 23, based on which the driving mechanism 33 is controlled to extend or retract in the linear direction, so as to drive the moving contact 31 to return to the position connected with the fixed contact 32 corresponding to the discharge end 23.

[0032] The power distribution network insulation resistance testing device 100 provided by the embodiment of the present application is designed with multiple output channels 11, thereby constructing an insulation resistance testing device framework capable of simultaneously or sequentially processing multiple testing requirements according to a logical sequence. On this basis, the channel switching module 30 and the driving mechanism 33 are introduced, thereby realizing dynamic switching between the output channels and the testing terminals. Finally, the control module 40 cooperates with the driving mechanism 33 to control the electrically conductive contact 31 to be electrically connected with the target position of the static contact 32, thereby completing a set of insulation resistance testing tasks. The insulation resistance testing device framework provided by the embodiment of the present application realizes the automatic testing of the insulation resistance of the power distribution network, improves the testing efficiency, and also reduces the error rate of manual operation.

[0033] Optionally, Figure 2 The structure of the channel switching module provided by the embodiment of the present application is shown in the figure. Figure 2 The static contact 32 of the present application comprises a first conductive part 321 and a first insulating sheath 322 sleeved on the outer periphery of the first conductive part 321; the movable contact 31 comprises a second conductive part 311 and a second insulating sheath 312 sleeved on the outer periphery of the second conductive part 311; when the movable contact 31 is connected with the static contact 32, the first conductive part 321 is in elastic interference contact with the second conductive part 311; when the movable contact 31 is not connected with the static contact 32, the minimum spacing distance between the first conductive part 321 and the second conductive part 311 is greater than a preset air insulation spacing; wherein the preset air insulation spacing is calculated based on the insulation resistance of the power distribution network to be tested.

[0034] The first conductive part 321 can be understood as a component for conducting electricity for the static contact 32; the first insulating sheath 322 can be understood as a protective layer sleeved on the outer periphery of the first conductive part 321, which is used to ensure the normal operation state of the circuit (to avoid abnormal situations such as current leakage or short circuit) and to ensure the safety of the operator. As above, the second conductive part 311 can be understood as a conductive component corresponding to the first conductive part 321 in the movable contact 31; the second insulating sheath 312 can be understood as a protective layer sleeved on the outer periphery of the second conductive part 311, which has a similar function to the first insulating sheath, and is used to ensure the normal operation state of the circuit. The preset air insulation spacing can be understood as the minimum spacing distance set to ensure electrical insulation when the movable contact 31 is not connected with the static contact 32.

[0035] It should be noted that the preset air insulation spacing is calculated based on the insulation resistance of the power distribution network to be tested, so as to ensure that the contacts will not be damaged or cause safety accidents due to electrical discharge in the disconnected state.

[0036] Specifically, the stationary contact 32 includes a first conductive portion 321 and a first insulating sleeve sleeved around the outer periphery of the first conductive portion 321. The moving contact 31 includes a second conductive portion 321 and a second insulating sleeve sleeved around the outer periphery of the second conductive portion 311. When the moving contact 31 is connected to the stationary contact 32, the first conductive portion 321 and the second conductive portion 311 achieve a good electrical connection through an elastic interference contact. When the moving contact 31 is not connected to the stationary contact 32, the minimum distance between the first conductive portion 321 and the second conductive portion 311 is greater than a preset air insulation distance to ensure that the first conductive portion 321 and the second conductive portion 311 are in an open state.

[0037] Optionally, the first insulating sheath and the second insulating sheath are made of insulating material; the thickness of the insulating material is calculated based on the insulation resistance of the power distribution network under test.

[0038] Insulating materials can be understood as electrical materials that have high resistance to electric current, thus preventing or greatly limiting the passage of current. For example, insulating materials can be epoxy resin materials.

[0039] It should be noted that the thickness of the insulating material is calculated based on the insulation resistance of the power distribution network under test to ensure sufficient insulation performance.

[0040] For example, let's design the air insulation distance and epoxy resin material thickness based on a 10kV voltage level requirement of 100GΩ insulation resistance. According to Ohm's law: R = ρ * d / A (where ρ is the volume resistivity, d is the material thickness, and A is the cross-sectional area of ​​the material); and the electric field formula: E = V / d (where V is the applied voltage and d is the material thickness), combining these two formulas, we can derive d = R * A / ρ. The resistivity of epoxy resin materials is typically around 10... 12 -10 16 Between Ω·m. Assume the volume resistivity of a certain epoxy resin material is 10... 14 Ω·m, at this point the required epoxy resin thickness is 1 mm. To ensure the reliability of the design, the epoxy resin thickness in this scheme is designed to be 2 mm.

[0041] Calculating air insulation gaps requires considering the breakdown voltage of air, in addition to the above factors. Under standard atmospheric pressure, the breakdown voltage of air is approximately 30 kV / cm (3000 V / mm). This means that if the air insulation gap is too small, air may undergo electrical breakdown and cease to function as an effective insulating medium. The volume resistivity of air is approximately 10⁻⁶ kV / cm. 13 Substituting Ω·m into the formula d=R*A / ρ, we can see that to achieve an insulation effect greater than 100GΩ at 10kV, the required air insulation gap is 10 mm. To ensure the reliability of the design, the air insulation gap in this scheme is set to 20 mm.

[0042] Specifically, the first and second insulation sheaths are arranged on the stationary contact 32 and the movable contact 31 respectively, which can effectively prevent the safety problem caused by the electric spark generated between the stationary contact 32 and the movable contact 31 when the stationary contact 32 and the movable contact 31 are in contact or disconnection. At the same time, by controlling the insulation interval between the first and second conductive parts 321 and 311 to be greater than the preset air insulation interval, the first and second conductive parts 321 and 311 are kept in a stable disconnection state when they are not in a connection state, which guarantees the safe and stable operation of the entire power distribution system and the good realization of the electrical performance.

[0043] Referring to Figure 2 , the first conductive part 321 includes two connecting pieces with a tapered section, and the second conductive part 311 includes two trapezoidal connecting pieces, and the upper bases of the trapezoidal connecting pieces are oppositely arranged.

[0044] The connecting piece can be understood as a component made of a material with good electrical conductivity, which is used to realize the electrical connection between the movable contact and the stationary contact.

[0045] Specifically, the first conductive part 321 includes two connecting pieces with a tapered section, and the second conductive part 311 includes two trapezoidal connecting pieces, and the upper bases of the trapezoidal connecting pieces are oppositely arranged. When the movable contact 31 and the stationary contact 32 are in contact, the connecting pieces with a tapered section can produce a certain elastic deformation, thereby realizing the close contact with the stationary contact 31. When the movable contact 32 and the stationary contact 31 are in contact, the trapezoidal connecting pieces can well adapt to the moving track of the movable contact, and when the movable contact 32 and the stationary contact 31 are in a connection state, the oppositely arranged upper bases of the trapezoidal connecting pieces ensure that the connecting pieces can provide a stable contact area.

[0046] The main body of the driving mechanism 33 is made of a rod-shaped epoxy resin material, which has good insulation and mechanical strength, ensuring stable operation of the driving mechanism in a complex electrical environment. The end of the driving mechanism 33 is provided with a horizontal hole, and a copper column is passed through the hole as a conductive part. One side of the copper column is provided with a wiring screw rod for connecting the output channel 11, and the other side is provided with a movable contact 31 composed of two sliding connection copper sheets with a conical section. This design enables the movable contact 31 to maintain good electrical conductivity and mechanical stability when in contact with the static contact 32. Correspondingly, there are four static contacts 32 arranged on the moving path of the movable contact 31, each composed of two trapezoidal copper sheets assembled with the inner bottom as an elastic contact interface. The static contact 32 is fixed through an epoxy resin tube to ensure its stability and reliability during testing. When the movable contact 31 moves in a straight line under the action of the driving mechanism 33, the sliding copper sheet with a conical section will elastically slide with the trapezoidal copper sheet of the static contact 32, thereby realizing switching between different test terminals 20.

[0047] Continuing to refer to Figure 2 , the driving mechanism 33 is used to fix the movable contact 31; the push rod control circuit 34 is used to control the extension movement of the electric telescopic rod when receiving the first control signal output by the control module 40, and control the retraction movement of the electric telescopic rod when receiving the second control signal output by the control module 40.

[0048] Specifically, in the power distribution network insulation resistance testing device, in order to realize automatic switching of the test terminal 20, when the push rod control circuit 34 in the driving mechanism 33 receives the first control signal, the driving mechanism 33 is controlled to extend; and when the control module 40 outputs the second control signal, the driving mechanism 33 is controlled to retract.

[0049] Specifically, in the power distribution network insulation resistance testing device, in order to realize automatic switching of the test terminal 20, when the push rod control circuit 34 in the driving mechanism 33 receives the first control signal, the driving mechanism 33 is controlled to extend; and when the control module 40 outputs the second control signal, the driving mechanism 33 is controlled to retract.

[0050] Figure 3 A circuit schematic diagram of a push rod control circuit provided by the embodiment of the present application is shown in Figure 3 Optionally, the push rod control circuit 34 includes a driving motor 351, a forward rotation driving branch 352 (see the branch shown by the green line in Figure 3 and a reverse rotation driving branch 353 (see the branch shown by the green line in Figure 3The positive rotation driving branch 352 is used for applying a positive voltage to the driving motor 351 to make the driving motor 351 rotate positively when the first control signal is received, so as to drive the driving mechanism 33 to extend and move; and the reverse rotation driving branch 353 is used for applying a reverse voltage to the driving motor 351 to make the driving motor 351 rotate reversely when the second control signal is received, so as to drive the driving mechanism 33 to retract and move.

[0051] Specifically, the control module 40 sends the first control signal or the second control signal to the push rod control circuit 34 according to the test requirement and the moving direction and target interval of the movable contact 31 between the initial position and the target position. When the target position is in the extension direction of the driving mechanism 33, the control module 40 sends the first control signal to the push rod control circuit 34, the positive rotation driving branch 352 is turned on, a positive voltage is applied to the driving motor 351, at this time the motor rotates positively, the driving mechanism 33 extends and moves, until the movable contact 31 is electrically connected with the test terminal 20 at the target position; similarly, when the target position is in the retraction direction of the driving mechanism 33, the control module 40 sends the second control signal to the push rod control circuit 34, the reverse rotation driving branch 353 is turned on, a reverse voltage is applied to the driving motor 351, at this time the driving motor 351 rotates reversely, the driving mechanism 33 retracts and moves, until the movable contact 31 is electrically connected with the test terminal 20 at the target position.

[0052] Specifically, the control module 40 sends the first control signal or the second control signal to the push rod control circuit 34 according to the test requirement and the moving direction and target interval of the movable contact 31 between the initial position and the target position. When the target position is in the extension direction of the driving mechanism 33, the control module 40 sends the first control signal to the push rod control circuit 34, the positive rotation driving branch 352 is turned on, a positive voltage is applied to the driving motor 351, at this time the motor rotates positively, the driving mechanism 33 extends and moves, until the movable contact 31 is electrically connected with the test terminal 20 at the target position; similarly, when the target position is in the retraction direction of the driving mechanism 33, the control module 40 sends the second control signal to the push rod control circuit 34, the reverse rotation driving branch 353 is turned on, a reverse voltage is applied to the driving motor 351, at this time the driving motor 351 rotates reversely, the driving mechanism 33 retracts and moves, until the movable contact 31 is electrically connected with the test terminal 20 at the target position.

[0053] Optionally, as shown in Figure 1 Optionally, as shown in

[0054] The discharge end 23 can include a grounding end and / or a common end, and both the grounding end and the common end are grounded. The grounding end is specially used for performing discharge operation, ensuring that residual charge can be effectively released after the test is completed. The common end is used for placing the movable contact 31 in a non-test state. The movable contacts 31 of all output channels are connected to the common end (which is usually grounded) by default in the non-test state, thereby preventing accidents and ensuring the safety and stability of the entire device.

[0055] Specifically, when the voltage sampling value of the output channel obtained by the control module 40 is not in the preset safe range, the circuit limits the size of the discharge current through the discharge resistor R (such as a cement resistor), thereby protecting the circuit and the device from the impact of instantaneous large current. When the voltage sampling value is reduced to the preset safe range or the voltage sampling value itself is in the preset safe range after a period of band-pass discharge, the discharge switch K is closed, and at this time, the circuit is in a short-circuit discharge state. The short-circuit discharge can quickly release the charge, reduce the discharge time, and improve the test efficiency.

[0056] Optionally, the power distribution network insulation resistance test device 100 provided in any one of the embodiments of the present application can further include a channel state indication module connected with the control module 40, used for indicating the connection mode of each output channel 11. The connection mode includes any one of the following: connecting the high-voltage output positive end 21, connecting the high-voltage output negative end 22, or connecting the discharge end 23.

[0057] Specifically, the channel state indication module can be composed of a group of indicator lights (such as LED lights) or digital display screens and the like. Each output channel corresponds to a group of indicator lights or display screens, which are used to display the connection state of the channel in real time. For example, the channel state indication module is a group of indicator lights. When the light is off, it indicates that it is connected to the common end (grounded). When the indicator light is green, it indicates that it is connected to the grounding end (discharge). When the indicator light is yellow, it indicates that it is connected to the high-voltage output negative end. When the indicator light is red, it indicates that it is connected to the high-voltage output positive end.

[0058] Optionally, the control module 40 in the power distribution network insulation resistance test device 100 provided in any one of the embodiments of the present application can be configured to: obtain a reference time required for the movable contact 31 to move between two adjacent stationary contacts 32, and calculate the working time length of the driving mechanism 33 in the corresponding output channel 11 according to the reference time and the initial position and the target position in different channels, and configure the target position as the position corresponding to the discharge end 23 when the driving time of the driving mechanism reaches the working time length.

[0059] The reference time can be understood as the time required for the movable contact 31 to move between two adjacent stationary contacts 32. The reference time can be obtained by experimental measurement or theoretical calculation and stored in the control module 40.

[0060] Specifically, based on the acquired reference time, in combination with the initial position and target position of the moving contact 31 in different output channels, the control module 40 calculates the working duration of the driving mechanism 33 in the corresponding output channel 11, and when the test task is completed, the target position is configured as the position corresponding to the discharge end 23 when the driving time of the driving mechanism reaches the working duration, and the moving contact 31 is controlled to move to the discharge end to automatically complete the discharge process.

[0061] For example, the reference time is acquired as follows: the time required for the moving contact 31 to move between adjacent static contacts 32 is acquired by a timer as the reference time.

[0062] Based on the power distribution network insulation resistance testing device 100 of the above embodiment, the present embodiment further provides a testing method of the power distribution network insulation resistance testing device 100. Figure 4 A flowchart of a power distribution network insulation resistance testing method provided by the present embodiment is shown in FIG. 6. Figure 4 The power distribution network insulation resistance testing method can be applied to any power distribution network insulation resistance testing device 100 provided by the present embodiment, and the power distribution network insulation resistance testing device 100 includes a plurality of output channels 11 and test terminals 20, the output channel 11 is connected to the moving contact 31, and the test terminal 20 is connected to the static contact 32. The specific steps of the method are as follows:

[0063] S110, acquiring the initial position of the moving contact corresponding to different output channels.

[0064] By default, the initial position of the moving contact when there is no test task is set at the discharge end, so as to ensure that all moving contacts are in a safe and known position before testing, and facilitate subsequent test operation.

[0065] Specifically, before performing the test, in order to ensure that the moving contact can be accurately moved from the current position to the target position, the control module will issue a detection instruction to acquire the current position information of each moving contact, i.e., the initial position, through a sensor or a position detection device.

[0066] S120, determining the target position of the moving contact in the corresponding output channel according to the test requirement.

[0067] The test requirement can be understood as a requirement proposed according to a specific test item and standard in the insulation performance detection or maintenance process of the power equipment, for example, but not limited to, any one of the following: phase-to-phase insulation resistance test requirement, phase-to-ground insulation resistance test requirement, transformer winding-to-winding insulation resistance test requirement, transformer winding-to-ground insulation resistance test requirement, and discharge requirement after test.

[0068] Specifically, according to the test requirement, the control module determines the target positions to which the moving contact in each output channel needs to be moved, and the target positions usually correspond to the test points of the power distribution network to be tested.

[0069] S130, according to the initial position and the target position, the control module controls the movement of the corresponding moving contact to make the moving contact electrically connected with the static contact corresponding to the target position.

[0070] Specifically, the control module calculates the distance and direction that the moving contact needs to move according to the information of the initial position and the target position. On this basis, the moving path and moving time of the moving contact corresponding to each output channel that needs to be tested are further calculated. Then, the forward rotation or reverse rotation time of the driving motor is calculated according to the moving path and moving time. Finally, the control module sends corresponding control instructions to the driving mechanism. After receiving the instructions, the driving mechanism drives the moving contact to move in a straight line until the moving contact is successfully electrically connected with the static contact corresponding to the target position.

[0071] The technical scheme of the embodiment of the present application acquires the initial positions of the moving contacts corresponding to different output channels, and then determines the current state of each output channel. Then, according to the test requirement, the target position of the moving contact in the corresponding output channel is determined to provide a clear target for subsequent test operation. On this basis, the control module controls the movement of the moving contact according to the information of the initial position and the target position, so that the moving contact is electrically connected with the static contact corresponding to the target position, thereby performing the insulation resistance test. Finally, after the test is completed, the moving contact is moved to the discharge end again and performs the discharge operation, ensuring the safe reset of the test device and ensuring the reliability and safety of the entire test process. The technical scheme of the embodiment of the present application realizes the insulation resistance test of the multi-channel automatic switching, improves the test efficiency, reduces the complexity and error rate of manual operation, and increases the safety of the insulation resistance test.

[0072] Figure 5 The flowchart of another power distribution network insulation resistance test method provided by the embodiment of the present application is a refinement or optimization of the above-mentioned embodiment. Specifically, the discharge end includes a grounding end and / or a common end; a discharge resistance and a discharge switch connected in parallel are arranged between the grounding end and the static contact; the control module is further configured to: acquire a voltage sampling value of the output channel, and control the discharge switch to be closed when the voltage sampling value is in a preset safe range.

[0073] As shown in Figure 5 , the method comprises:

[0074] S210, acquiring the initial positions of the moving contacts corresponding to different output channels.

[0075] S220, determining a target position of the moving contact in the corresponding output channel according to the test requirement.

[0076] S230, controlling the corresponding moving contact to move according to the initial position and the target position, so that the moving contact is electrically connected with the fixed contact corresponding to the target position.

[0077] S231, moving the moving contact to the discharging end.

[0078] Specifically, when a set of insulation voltage tests are completed, it is necessary to perform discharging operation on the test circuit, at this time, the push rod control circuit drives the electric telescopic rod to move the moving contact to the corresponding fixed contact of the discharging end.

[0079] S232, obtaining a voltage sampling value of the output channel.

[0080] Specifically, the control module obtains the voltage sampling value of the output channel, and the obtained voltage sampling value of the output channel is used to judge whether the discharging resistor needs to be connected for protection discharging.

[0081] S233, controlling the discharging switch to be closed when the voltage sampling value is in a preset safe range.

[0082] Specifically, when the voltage sampling value of the output channel is higher than the safe range, the discharging end is connected in series with the discharging resistor (such as a cement resistor), and the electric charge is discharged after passing through the cement resistor, so as to avoid the impact of the excessive current on the circuit and the equipment; when the voltage sampling value of the output channel is in the safe range, the discharging switch connected in parallel with the discharging resistor is closed at this time, and the electric charge is connected with the ground through the wire to achieve the purpose of rapid discharging.

[0083] The technical scheme of the embodiment of the application distinguishes the discharging process into two modes of band-pass discharging and direct discharging by detecting the voltage sampling value of the output channel, the energy release of the band-pass discharging mode is relatively gentle to avoid the impact of the excessive current on the circuit and the equipment, when the voltage sampling value drops to the safe range, or the voltage sampling value itself is in the safe range, the control module controls the discharging switch to be closed, and the discharging process is rapidly completed.

[0084] Figure 6 The flowchart of another power distribution network insulation resistance test method provided by the embodiment of the application is a refinement or optimization of the above-mentioned embodiment, specifically, the control module is configured to: obtain a reference time required for the moving contact to move between two adjacent fixed contacts, and calculate the working time length of the driving mechanism in the corresponding output channel according to the reference time and the initial position and the target position in different output channels, and configure the target position as the position corresponding to the discharging end when the driving time of the driving mechanism reaches the working time length.

[0085] As Figure 6As shown, the method comprises:

[0086] S310, acquiring initial positions of the moving contact corresponding to different output channels.

[0087] S320, determining target positions of the moving contact in the corresponding output channel according to test requirements.

[0088] S321, acquiring a reference time required for the moving contact to move between two adjacent stationary contacts.

[0089] Specifically, the reference time can be understood as the time required for the moving contact to move between two adjacent stationary contacts, and the reference time can be obtained by experimental determination or theoretical calculation.

[0090] S322, calculating working durations of the driving mechanism in the corresponding output channel according to the reference time and the initial positions and the target positions in the different output channels.

[0091] Specifically, based on the acquired reference time, the initial positions and the target positions of the moving contact in the different output channels, the control module calculates the working durations of the driving mechanism in the corresponding output channel. The distance control is converted into time control, which simplifies the control logic and ensures that the moving contact can be timely and accurately moved to the target position.

[0092] S323, configuring the target position as a position corresponding to the discharge end when the driving time of the driving mechanism reaches the working duration.

[0093] Specifically, when the driving time of the driving mechanism reaches the working duration, it is considered that the current test task is completed, and the target position is configured as a position corresponding to the discharge end. At this time, according to the target position, the driving mechanism controls the moving contact to be connected with the discharge end.

[0094] S330, controlling the corresponding moving contact to move according to the initial position and the target position, so that the moving contact is electrically connected with the stationary contact corresponding to the target position.

[0095] The embodiment of the application introduces the concept of reference time, converts the complex distance control into intuitive time control, simplifies the control logic, and enables the moving contact to be quickly and accurately moved to the target position, thereby fully ensuring the accuracy of the test. After the preset working duration ends, the application automatically sets the target position as a position corresponding to the discharge end, thereby realizing the function of automatic discharge and improving the safety and convenience of operation.

[0096] Note that the above merely describes preferred embodiments of the present application and the principles of the technology applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, modifications, combinations and substitutions can be made by those skilled in the art without departing from the scope of the present application. Therefore, although the present application has been described in detail through the above embodiments, the present application is not limited to the above embodiments, and includes more other embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the claims.

Claims

1. A device for testing the insulation resistance of a power distribution network, characterized in that, include: Multiple output channels, which are used to connect to the power distribution network under test; The test terminals include at least: the high-voltage output positive terminal, the high-voltage output negative terminal, and the discharge terminal; A channel switching module is configured to correspond one-to-one with the output channels. The channel switching module includes a stationary contact, a moving contact, and a driving mechanism. The stationary contact is connected one-to-one with the test terminal, the moving contact is connected to the output channel, and the driving mechanism is used to drive the moving contact to move in a straight line. The control module is connected to the control terminal of the drive mechanism and is used to obtain the initial position of the moving contact corresponding to different output channels, determine the target position of the moving contact in the corresponding output channel according to the test requirements, and control the corresponding drive mechanism to extend or retract along a straight line according to the initial position and the target position, so that the moving contact is electrically connected to the stationary contact corresponding to the target position. The stationary contact includes a first conductive part and a first insulating sleeve sleeved on the outer periphery of the first conductive part. The moving contact includes a second conductive part and a second insulating sleeve sleeved on the outer periphery of the second conductive part; When the moving contact is connected to the stationary contact, the first conductive part and the second conductive part are in elastic interference contact. When the moving contact and the stationary contact are not connected, the minimum distance between the first conductive part and the second conductive part is greater than a preset air insulation distance; wherein, the preset air insulation distance is calculated based on the insulation resistance of the power distribution network under test; The first conductive part includes two connecting pieces with tapered cross-sections; The second conductive part includes two trapezoidal connecting pieces, with the upper bottom surfaces of the trapezoids facing each other.

2. The power distribution network insulation resistance testing device according to claim 1, characterized in that, The first insulating sleeve and the second insulating sleeve are made of insulating material; The thickness of the insulating material is calculated based on the insulation resistance of the power distribution network under test.

3. The power distribution network insulation resistance testing device according to claim 1, characterized in that, The drive mechanism includes: An electric telescopic rod is used to fix the moving contact. The push rod control circuit is used to control the extension movement of the electric telescopic rod when receiving a first control signal output by the control module; and to control the retraction movement of the electric telescopic rod when receiving a second control signal output by the control module.

4. The power distribution network insulation resistance testing device according to claim 3, characterized in that, The push rod control circuit includes: a drive motor, a forward drive branch, and a reverse drive branch; The drive motor is engaged with the electric telescopic rod; The forward drive branch is used to apply a positive voltage to the drive motor when the first control signal is received, so that the drive motor rotates forward and drives the electric telescopic rod to extend. The reverse drive branch is used to apply a reverse voltage to the drive motor when the second control signal is received, so that the drive motor reverses and drives the electric telescopic rod to retract.

5. The power distribution network insulation resistance testing device according to claim 1, characterized in that, The discharge terminal includes a ground terminal and / or a common terminal; A discharge resistor and a discharge switch are connected in parallel between the grounding terminal and the stationary contact. The control module is also configured to: acquire the voltage sampling value of the output channel, and control the discharge switch to close when the voltage sampling value is within a preset safe range.

6. The power distribution network insulation resistance testing device according to any one of claims 1-5, characterized in that, Also includes: A channel status indicator module, connected to the control module, is used to indicate the connection mode of each output channel; The connection method includes any of the following: connecting to the positive terminal of the high voltage output, connecting to the negative terminal of the high voltage output, or connecting to the discharge terminal.

7. The power distribution network insulation resistance testing device according to any one of claims 1-6, characterized in that, The control module is configured to: obtain the reference time required for the moving contact to move between two adjacent stationary contacts, calculate the working time of the driving mechanism in the corresponding output channel based on the reference time and the initial position and the target position in different output channels, and configure the target position as the position corresponding to the discharge end when the driving time of the driving mechanism reaches the working time.

8. A method for testing the insulation resistance of a power distribution network, characterized in that, The method is based on the distribution network insulation resistance testing device according to any one of claims 1 to 7, wherein the distribution network insulation resistance testing device includes multiple output channels and test terminals, the output channels are connected to moving contacts, and the test terminals are connected to stationary contacts, and the method includes: Obtain the initial position of the moving contact corresponding to different output channels; Determine the target position of the moving contact in the corresponding output channel according to the test requirements; The moving contact is controlled to move according to the initial position and the target position, so that the moving contact is electrically connected to the stationary contact corresponding to the target position.

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