A three-phase circuit detection control box for high-voltage virtual power source

Abstract

The present invention relates to a three-phase loop detection control box of a high-voltage virtual power source, comprising a chassis body, a control unit, a high-voltage virtual power source and a current detection transformer arranged inside the chassis body, and a high-voltage side port and a low-voltage side port arranged on the chassis body, wherein the high-voltage side port comprises a high-voltage virtual power source port and a three-phase high-voltage virtual power source port, wherein the control unit is connected to the low-voltage side port through an optical fiber, wherein the control unit is connected to the high-voltage virtual power source port through the current detection transformer, wherein the control unit is connected to the three-phase high-voltage virtual power source port through a plurality of switch arrays, wherein the three-phase high-voltage virtual power source port is connected to a distribution switch to be tested. Compared with the prior art, the present invention has the advantages of small size, low power consumption, low cost, and solving the problem of inter-phase crosstalk caused by a magnetic potential synthesis zero-sequence current transformer.

Description

Technical Field

[0001] The invention relates to the technical field of power distribution network detection, and in particular to a three-phase loop detection control box for a high-voltage virtual power source. Background Art

[0002] As the core equipment for realizing distribution network and automation, the overall performance and quality level of distribution switches and terminals is directly related to the safety of distribution network, power supply reliability, and the development of distribution automation. Therefore, corresponding detection systems are needed to simulate the operation of distribution network and conduct all-round testing and verification of network-connected equipment.

[0003] In recent years, with the extensive application of primary and secondary integrated pole switches and ring network cabinets, power supply companies at all levels are building corresponding test systems. Most of them use three sets of high-voltage current boosters and boosters as virtual power sources to simulate the three-phase operating conditions of the distribution network, and complete the accuracy detection of the three-phase current, three-phase voltage, zero-sequence current, zero-sequence voltage and line loss related parameters of the primary and secondary integrated complete switches and ring network cabinets. This detection belongs to the telemetry of the three telemetry. Telemetry is the basis for the terminal to analyze signal characteristics and judge line faults. Therefore, the detection of telemetry accuracy is crucial. The existing technology uses three sets of independent current boosters and booster components to connect the high-voltage side current loop of each phase with the high-voltage end of the same-phase high-voltage side voltage loop, realizing a high-voltage virtual power source. The ABC three-phase high-voltage virtual power sources are independent of each other and do not interfere with each other. The reference potential of the high-voltage side is the earth. Each phase of the high-voltage virtual power source controls the current and voltage of the input end of the current booster and booster and their phase relationship through the main control unit on the low-voltage side to adjust the current, voltage and phase of the high-voltage side. The insulation part between the high-voltage side and the low-voltage side is realized by the current booster and booster.

[0004] The existing technical solutions are relatively easy to control the magnitude and phase relationship of three-phase current and three-phase voltage, but the zero-sequence current and zero-sequence voltage can only be synthesized by vector synthesis of ABC three-phase current and three-phase voltage. The three-phase current and three-phase voltage need to control their magnitude and phase at the same time. Since the accuracy of the current-boosting and voltage-boosting components can only reach 5 / 10,000 at present, it is difficult to ensure that the synthesized zero-sequence current and zero-sequence voltage reach a stability of 5 / 10,000. If a zero-sequence current transformer synthesized by magnetic potential is used in the distribution switch under test, the high-voltage current loop of the ABC three-phase will generate phase-to-phase crosstalk through the zero-sequence transformer under test, and its current magnitude cannot be stably controlled, which has detection limitations. The existing technical solutions cannot detect the residual characteristics of the zero-sequence current transformer, and the residual characteristic index directly affects the results of high-resistance grounding detection. Most of the existing technical solutions use three sets of independent high-voltage virtual power sources, which are expensive, large in size, heavy in weight, and have poor insulation consistency. For detection units with low budgets and limited space, this solution cannot meet their needs, let alone meet the needs of mobility. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a high-voltage virtual power source three-phase circuit detection control box.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A high-voltage virtual power source three-phase loop detection control box comprises a chassis body, a control unit, a high-voltage virtual power source and a current detection transformer arranged inside the chassis body, and a high-voltage side port and a low-voltage side port arranged on the chassis body, wherein the high-voltage side port comprises a high-voltage virtual power source port and a three-phase high-voltage virtual power source port, the control unit is connected to the low-voltage side port via an optical fiber, the control unit is connected to the high-voltage virtual power source port via the current detection transformer, the control unit is connected to the three-phase high-voltage virtual power source port via multiple switch arrays, and the three-phase high-voltage virtual power source port is connected to a distribution switch to be tested.

[0008] Preferably, the low-voltage side port includes a 220VAC port and a fiber optic communication port.

[0009] Preferably, a high-voltage transformer and a rectifier and voltage-stabilizing circuit are also provided in the control box, one end of the high-voltage transformer is connected to the 220VAC port of the low-voltage side port, and the other end is connected to the rectifier and voltage-stabilizing circuit, the output end of the rectifier and voltage-stabilizing circuit is connected to the control unit, the control unit is connected to the optical fiber communication port of the low-voltage side port, and one end of the high-voltage transformer is connected to the positive port of the high-voltage virtual power source.

[0010] Preferably, the multiple groups of switch arrays include two groups of switch arrays connected to the high-voltage virtual power source port, a second switch array arranged between the three-phase high-voltage virtual power source ports, and a third switch array arranged between the three-phase high-voltage virtual power source port and the high-voltage virtual power source port.

[0011] Preferably, each group of switch arrays connected to the high-voltage virtual power source port includes three first switch arrays connected in parallel, wherein the three first switch arrays of the first group of switch arrays are respectively connected between the current detection transformer and the positive port of the A, B, and C phase high-voltage virtual power source, and the current detection transformer is connected to the positive port of the high-voltage virtual power source, and the three first switch arrays of the other group of switch arrays are respectively connected between the negative port of the high-voltage virtual power source and the negative port of the A, B, and C phase high-voltage virtual power source.

[0012] Preferably, the second switch array arranged between the three-phase high-voltage virtual power source ports includes a second switch array arranged between each first switch array in the first group of switch arrays and the connecting lines between the positive ports of the A, B, and C phase high-voltage virtual power sources, and a second switch array arranged between each first switch array in the second group of switch arrays and the connecting lines between the negative ports of the A, B, and C phase high-voltage virtual power sources.

[0013] Preferably, the third switch array arranged between the three-phase high-voltage virtual power source port and the high-voltage virtual power source port is arranged between the connecting line of one of the first switch arrays in the first group of switch arrays and the positive port of the C-phase high-voltage virtual power source and the negative port of the high-voltage virtual power source.

[0014] Preferably, each switch array is a switch array composed of twenty magnetic latching relays connected in parallel and a copper busbar, the twenty magnetic latching relays are fixed on the copper busbar, and each copper busbar has a current carrying capacity of at least 1000A.

[0015] Preferably, the distribution switch under test is a built-in or external three-phase current and voltage transformer, a zero-sequence current and voltage transformer, or a complete set of phase sequence current and voltage, zero sequence current and voltage, and line loss module electric energy and terminal.

[0016] Preferably, the high-voltage virtual power source port is fixedly led out using an insulating plate, and its terminal uses an M20 copper stud, and each port is provided with an air discharge gap of more than 180 mm from the low-voltage side port.

[0017] The high-voltage virtual power source three-phase loop detection control box provided by the present invention has at least the following beneficial effects compared with the prior art:

[0018] 1) The present invention is a chassis-type design, and the chassis can be moved to different positions at any time for detection operations. It is easy to use and has a wide range of applications. It has the advantages of small size, light weight, low power consumption, low cost, and portability.

[0019] 2) Through the control of the switch array by the control unit, it can not only meet the detection requirements of distribution switches or primary and secondary integrated systems, but also solve the problem of low stability of zero-sequence current and zero-sequence voltage high-voltage side signals. A group of high-voltage virtual power sources is used to completely solve the phase-to-phase crosstalk problem caused by the magnetic potential synthetic zero-sequence current transformer.

[0020] 3) The present invention is suitable for using a group of high-voltage virtual power sources to realize the accuracy detection of telemetry signals such as three-phase current and voltage transformers, zero-sequence current and voltage transformers or complete sets of phase-sequence current and voltage, zero-sequence current and voltage, and line loss module electric energy in distribution switches. It can also complete the detection of the residual characteristics of the zero-sequence current transformer and its complete set of zero-sequence current transformers, providing a basis for the accuracy of analysis and judgment of ground faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the internal connection structure of the three-phase loop detection control box of the high-voltage virtual power source in the embodiment;

[0022] Figure 2 A schematic diagram of the connection relationship of each switch array of the three-phase loop detection control box of the high-voltage virtual power source in the embodiment;

[0023] Figure 3 It is a flow chart of the control unit of the high-voltage virtual power source loop control box for detection in the embodiment;

[0024] Figure 2 As shown in the bid number:

[0025] 1. L1AP1 switch array; 2. L1BP1 switch array; 3. ABP1 switch array; 4. L1CP1 switch array; 5. BCP1 switch array; 6. L2AP2 switch array; 7. ABP2 switch array; 8. BCP2 switch array; 9. L2BP2 switch array; 10. L2CP2 switch array; 11. CP1L2 switch array; 12. Positive terminal of high-voltage virtual power source; 13. Current detection transformer; 14. Negative terminal of high-voltage virtual power source; 15. Positive terminal of A-phase high-voltage virtual power source; 16. Negative terminal of A-phase high-voltage virtual power source; 17. Positive terminal of B-phase high-voltage virtual power source; 18. Negative terminal of B-phase high-voltage virtual power source; 19. Positive terminal of C-phase high-voltage virtual power source; 20. Negative terminal of C-phase high-voltage virtual power source; 21. Power distribution switch under test. DETAILED DESCRIPTION

[0026] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should belong to the scope of protection of the present invention.

[0027] Example

[0028] The present invention relates to a three-phase loop detection control box of a high-voltage virtual power source, which is suitable for realizing the accuracy detection of telemetry signals such as three-phase current and voltage transformers, zero-sequence current and voltage transformers or complete sets of phase sequence current and voltage, zero-sequence current and voltage, and electric energy of line loss modules in distribution switches using a group of high-voltage virtual power sources. The high-voltage virtual power source loop control box is placed on the high-voltage side, with the same potential as the high-voltage side, and there is no insulation problem; and it has a current carrying capacity of more than 1000A, and the high-voltage virtual power source loop control is realized by setting the opening and closing states of switch arrays at different positions.

[0029] The high-voltage virtual power source circuit control box for detection of the present invention comprises a chassis body, a control unit and a high-voltage virtual power source arranged inside the chassis body. The control unit communicates with the low-voltage side through optical fiber, thereby solving the insulation problem between high and low voltages. The current of the high-voltage virtual power source circuit is collected through a current detection mutual inductor to realize an overcurrent protection function. The opening and closing control of switch arrays at different positions is realized through a driving circuit.

[0030] The internal connection relationship of the high-voltage virtual power source circuit control box for detection is as follows Figure 1 The internal power supply of the control box of the high-voltage virtual power source loop for detection is realized by a small-capacity high-voltage transformer to achieve the conversion from the low-voltage side 220VAC to the high-voltage side 30VAC, and outputs 24VDC through the rectifier and voltage stabilization circuit to power the control unit. The insulation voltage between the primary and secondary sides of the high-voltage transformer is more than 20kV, which realizes the isolation of high and low voltage measurement.

[0031] The ports of the high-voltage virtual power source loop control box for detection are simple, including a high-voltage side port and a low-voltage side port: the high-voltage side input port of the high-voltage side port is a high-voltage virtual power source port, and the high-voltage side output port of the high-voltage side port is a three-phase high-voltage virtual power source port; the high-voltage virtual power source port includes a high-voltage virtual power source positive port and a high-voltage virtual power source negative port. The three-phase high-voltage virtual power source port includes a positive port of a phase A high-voltage virtual power source, a negative port of a phase A high-voltage virtual power source, a positive port of a phase B high-voltage virtual power source, a negative port of a phase B high-voltage virtual power source, a positive port of a phase C high-voltage virtual power source, and a negative port of a phase C high-voltage virtual power source. The high-voltage virtual power source ports of each phase are respectively connected to the distribution switch under test.

[0032] The 11 switch arrays arranged in different positions in the detection high-voltage virtual power source circuit control box are used to connect the three-phase high-voltage virtual power source circuit, and detection is performed by controlling the opening and closing of different switch arrays. The present invention has a total of 11 switch arrays, including two groups of switch arrays connected to the high-voltage virtual power source ports, a switch array arranged between the three-phase high-voltage virtual power source ports, and a switch array arranged between the three-phase high-voltage virtual power source ports and the high-voltage virtual power source ports.

[0033] One end of the high-voltage transformer is connected to the 220VAC port of the low-voltage side port, and the other end is connected to the rectifier and voltage regulator circuit. The output end of the rectifier and voltage regulator circuit is connected to the control unit, and the control unit is connected to the optical fiber communication port of the low-voltage side port. Each switch array is connected to the control unit respectively.

[0034] Combination Figure 2It can be seen from the circuit connection relationship of each switch array that the first group of switch arrays connected to the high-voltage virtual power source port includes three switch arrays connected in parallel, which can be represented by L1AP1 switch array 1, L1BP1 switch array 2, and L1CP1 switch array 3, respectively. Each switch array in this group is connected to the control unit. The input end of each switch array in this group is connected to the output end of the current detection transformer 13, and the input end of the current detection transformer 13 is connected to the positive electrode port 12 of the high-voltage virtual power source. The output end of each switch array in this group is respectively connected to the positive electrode port 15 of the A-phase high-voltage virtual power source, the positive electrode port 17 of the B-phase high-voltage virtual power source, and the positive electrode port 19 of the C-phase high-voltage virtual power source. The positive electrode port 15 of the A-phase high-voltage virtual power source, the positive electrode port 17 of the B-phase high-voltage virtual power source, and the positive electrode port 19 of the C-phase high-voltage virtual power source are respectively connected to one end of the distribution switch 21 under test. The current detection transformer 13 is connected to the control unit. The distribution switch 21 under test is a built-in or external three-phase current and voltage transformer, a zero-sequence current and voltage transformer, or a complete set of phase sequence current and voltage, zero sequence current and voltage, and line loss module electric energy and terminal.

[0035] The names L1AP1, L1BP1, and L1CP1 of the above three switch arrays respectively represent the first group of three switch arrays connected to the positive ports of the A, B, and C phase high-voltage virtual power sources. This naming can also be expressed in other ways. The naming used here is just for the convenience of explanation.

[0036] The second group of switch arrays connected to the high-voltage virtual power source port includes three switch arrays connected in parallel, which can be represented by L2AP2 switch array 6, L2BP2 switch array 9, and L2CP2 switch array 10, respectively. Each switch array in this group is connected to the control unit. The input end of each switch array in this group is connected to the negative electrode port 14 of the high-voltage virtual power source. The output end of each switch array in this group is respectively connected to the negative electrode port 16 of the A-phase high-voltage virtual power source, the negative electrode port 18 of the B-phase high-voltage virtual power source, and the negative electrode port 20 of the C-phase high-voltage virtual power source. The negative electrode port 16 of the A-phase high-voltage virtual power source, the negative electrode port 18 of the B-phase high-voltage virtual power source, and the negative electrode port 20 of the C-phase high-voltage virtual power source are respectively connected to the other end of the distribution switch 21 under test.

[0037] The names L2AP2, L2BP2, and L2CP2 of the three switch arrays in the second group mentioned above respectively represent the three switch arrays in the second group connected to the negative ports of the A, B, and C phase high-voltage virtual power sources respectively. This naming can also be expressed in other ways. The naming used here is just for the convenience of explanation.

[0038] The switch arrays arranged between the three-phase high-voltage virtual power source ports and the switch arrays arranged between the three-phase high-voltage virtual power source ports and the high-voltage virtual power source ports include an ABP1 switch array 3, a BCP1 switch array 5, a CP1L2 switch array 11, an ABP2 switch array 7, and a BCP2 switch array 8, each of which is connected to a control unit. The naming method of each switch array is a brief naming method based on its installation location, and this naming can also be expressed in other ways. The naming adopted here is just for the convenience of explaining.

[0039] The ABP1 switch array 3 is arranged between the connection line between the L1AP1 switch array 1 and the positive terminal 15 of the A-phase high-voltage virtual power source and the connection line between the L1BP1 switch array 2 and the positive terminal 17 of the B-phase high-voltage virtual power source. The BCP1 switch array 2 is arranged between the connection line between the L1BP1 switch array and the positive terminal 17 of the B-phase high-voltage virtual power source and the connection line between the L1CP1 switch array 4 and the positive terminal 19 of the C-phase high-voltage virtual power source. The CP1L2 switch array 11 is arranged between the connection line between the L1CP1 switch array 4 and the positive terminal 19 of the C-phase high-voltage virtual power source and the negative terminal 14 of the high-voltage virtual power source.

[0040] The ABP2 switch array 7 is arranged between the connection line between the L2AP2 switch array 6 and the negative terminal 16 of the A-phase high-voltage virtual power source and the connection line between the L2BP2 switch array 9 and the negative terminal 18 of the B-phase high-voltage virtual power source. The BCP2 switch array 8 is arranged between the connection line between the L2BP2 switch array 9 and the negative terminal 18 of the B-phase high-voltage virtual power source and the connection line between the L2CP2 switch array 10 and the negative terminal 20 of the C-phase high-voltage virtual power source.

[0041] In the present invention, 11 switch arrays use a switch array with a large current switching capacity of 1000A. Preferably, a switch array composed of 20 large current magnetic latching relays in parallel and a copper busbar is used. The 20 magnetic latching relays are fixed on the copper busbar, and each large current relay shunts the copper busbar. The copper busbar has a current carrying capacity of more than 1000A. The 20 magnetic latching relays are uniformly controlled by the same control port to achieve synchronous separation and combination.

[0042] Furthermore, Figure 1 One end of the high-voltage transformer needs to be connected to the positive port of the high-voltage virtual power source to provide a reference potential for the control unit and is connected to the rectifier and voltage stabilization circuit. The other end of the high-voltage transformer is directly connected to the rectifier and voltage stabilization circuit to ensure that the rectifier and voltage stabilization circuit, the control unit, and the control coil of the magnetic latching relay are at the same potential as the high-voltage virtual power source.

[0043] In this embodiment, Figure 1The medium and high voltage virtual power source ports are fixed with insulating plates and have a current capacity of more than 1000A. The terminal blocks should use M20 copper studs. Each port and the low voltage side need to ensure an air discharge gap of more than 180mm. The ports are at the same potential and do not need to be considered.

[0044] In order to improve the detection efficiency, as a preferred solution, the high-voltage virtual power source supports an operating mode with a maximum current of 1000A and a maximum voltage of 12kV.

[0045] Figure 1 Although the central control unit is a low-voltage, low-power circuit, its reference potential is the high-voltage side of the high-voltage virtual power source, and the communication link with the low-voltage side uses multi-mode optical fiber, which not only solves the insulation problem, but also solves the problem of communication stability.

[0046] like Figure 3 As shown in the figure, the process of the control unit is as follows: first, all switch arrays are disconnected, the current of the high-voltage virtual power source is 0A, and the voltage is 0V; then the control unit receives the control command of the optical fiber port, and implements the opening and closing control of each switch array according to the command, while the current detection transformer collects the current of the high-voltage virtual power source in real time. If the control unit is successful, it returns a success command, and if the control fails, it returns a failure command.

[0047] If the control unit receives a query command from the optical fiber port, it can read the high-voltage virtual power source current collected by the current detection transformer and return the data. If it is determined that overcurrent occurs, all switch arrays are disconnected. If no overcurrent occurs, the real-time collection of the high-voltage virtual power source current continues.

[0048] The specific working process of the three-phase loop detection control box of the high-voltage virtual power source of the present invention is as follows:

[0049] (1) Power on, all switch arrays are in the off state, the high-voltage virtual power source current is 0A, and the voltage is 0V;

[0050] (2) Sending commands to the control unit via optical fiber, the control unit controls the L1AP1, L2AP2, BCP1, L2CP2 switch arrays to close, and the rest to open, the high-voltage virtual power source current collected by the current detection transformer changes, the voltage is 0V, and the A, B, C three-phase current transformer and telemetry three-phase current detection are realized;

[0051] (3) Sending commands through optical fiber, L1CP1 and L2CP2, L1BP1 and L2BP2, L1CP1 and L2CP2 switch arrays are closed, and the rest are disconnected, the current of the high-voltage virtual power source changes, and the voltage is 0V, realizing zero-sequence current transformer and remote sensing zero-sequence current detection;

[0052] (4) Sending commands via optical fiber closes the L1CP1, ABP2, BCP2, and CP2L2 switch arrays, changes the current of the high-voltage virtual power source, and turns the voltage to 0 V. The rest are disconnected to achieve the residual characteristic detection of the zero-sequence current transformer.

[0053] (5) Send commands through optical fiber, all switch arrays are closed, the voltage of the high-voltage virtual power source changes, and the current is 0V, realizing the detection of phase sequence and zero sequence voltage transformers and telemetry voltage.

[0054] (6) A command is sent through the optical fiber, and the L1AP1, L2AP2, BCP1, and L2CP2 switch arrays are closed, while the others are opened. The current and voltage of the high-voltage virtual power source change, and the phase relationship between the current and voltage is changed, thereby realizing the detection of the electric energy of the line loss module.

[0055] In the above step (3), the B-phase current is equal to the A-phase and C-phase currents, but has opposite phases. When detecting the B-phase phase, it is 180 degrees different from the standard phase. Phase reversal or software correction can be performed on the secondary side of the transformer under test without affecting the accuracy of the detection.

[0056] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technical field can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A high voltage virtual power source three-phase circuit detection control box, characterized in that: It includes a chassis body, a control unit, a high-voltage virtual power source and a current detection transformer arranged inside the chassis body, and a high-voltage side port and a low-voltage side port arranged on the chassis body, wherein the high-voltage side port includes a high-voltage virtual power source port and a three-phase high-voltage virtual power source port, the control unit is connected to the low-voltage side port through an optical fiber, the control unit is connected to the high-voltage virtual power source port through the current detection transformer, the control unit is connected to the three-phase high-voltage virtual power source port through multiple groups of switch arrays, and the three-phase high-voltage virtual power source port is connected to a distribution switch to be tested; The low-voltage side port includes a 220VAC port and an optical fiber communication port; The plurality of switch arrays include two switch arrays connected to the high-voltage virtual power source ports, a second switch array disposed between the three-phase high-voltage virtual power source ports, and a third switch array disposed between the three-phase high-voltage virtual power source ports and the high-voltage virtual power source port; Each group of switch arrays connected to the high-voltage virtual power source port includes three first switch arrays connected in parallel, wherein the three first switch arrays of the first group of switch arrays are respectively connected between the current detection transformer and the positive electrode port of the A, B, and C phase high-voltage virtual power source, and the current detection transformer is connected to the positive electrode port of the high-voltage virtual power source, and the three first switch arrays of the other group of switch arrays are respectively connected between the negative electrode port of the high-voltage virtual power source and the negative electrode port of the A, B, and C phase high-voltage virtual power source; The second switch array provided between the ports of the three-phase high-voltage virtual power source includes a second switch array provided between each first switch array in the first group of switch arrays and a connection line between the positive electrode ports of the A, B, and C phase high-voltage virtual power sources, and a second switch array provided between each first switch array in the second group of switch arrays and a connection line between the negative electrode ports of the A, B, and C phase high-voltage virtual power sources; The third switch array provided between the three-phase high-voltage virtual power source port and the high-voltage virtual power source port is provided between a connection line between one of the first switch arrays in the first group of switch arrays and the positive port of the C-phase high-voltage virtual power source and the negative port of the high-voltage virtual power source; Each switch array uses a switch array composed of twenty magnetic latching relays connected in parallel and a copper busbar. The twenty magnetic latching relays are fixed on the copper busbar. Each copper busbar has a current carrying capacity of at least 1000A.

2. The high-voltage virtual power source three-phase circuit detection control box according to claim 1 is characterized in that: The control box is also provided with a high-voltage transformer and a rectifier and voltage-stabilizing circuit. One end of the high-voltage transformer is connected to the 220VAC port of the low-voltage side port, and the other end is connected to the rectifier and voltage-stabilizing circuit. The output end of the rectifier and voltage-stabilizing circuit is connected to the control unit, and the control unit is connected to the optical fiber communication port of the low-voltage side port. One end of the high-voltage transformer is connected to the positive port of the high-voltage virtual power source.

3. The high-voltage virtual power source three-phase circuit detection control box according to claim 1 is characterized in that: The distribution switch under test is a built-in or external three-phase current and voltage transformer, a zero-sequence current and voltage transformer, or a complete set of phase-sequence current and voltage, zero-sequence current and voltage, and line loss module electric energy and terminals.

4. The high-voltage virtual power source three-phase circuit detection control box according to claim 1 is characterized in that: The high-voltage virtual power source port is fixed and led out with an insulating plate, and its terminal uses M20 copper studs. Each port is provided with an air discharge gap of more than 180mm with the low-voltage side port.

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