Three-phase five-column type coal mine voltage transformer based on resistor voltage division

Abstract

The present invention provides a three-phase five-column type coal mine voltage transformer based on resistor voltage division, which includes an insulating housing, a circuit device, and epoxy resin encapsulated in the insulating housing. The circuit device includes five terminal posts, namely A-phase, B-phase, C-phase, zero-sequence voltage, and neutral point, fixedly arranged on the insulating housing, three input high-voltage insulating wires for introducing voltage signals into the insulating housing from the outside, and a circuit board fixedly arranged in the insulating housing. The circuit board is provided with a resistor voltage division module, an active filter acquisition module electrically connected to the resistor voltage division module for acquiring, filtering, conditioning, and outputting the acquired voltage signals, and an isolation output module electrically connected to the active filter acquisition module for isolating voltage signals. The isolation output module is electrically connected to the five terminal posts. Through the overall structural design, the present invention can effectively solve the problems of energy consumption, material consumption, high cost, and the need to improve work safety and reliability existing in the existing electromagnetic three-phase five-column voltage transformers in coal mines.

Description

Technical Field

[0001] The present invention relates to the technical field of mine power supply measurement components, and in particular to a three-phase five-column voltage transformer for coal mines based on resistance voltage division. Background Art

[0002] In underground coal mine power supply systems, three-phase five-column voltage transformers are widely used as measuring devices for three-phase voltage and zero-sequence voltage in a variety of products with voltage levels of 10kV, 6kV, and 3.3kV, providing measurement and protection voltage signals for relay protection devices.

[0003] The three-phase, five-pole voltage transformers currently used in underground coal mines are electromagnetic three-phase, five-pole voltage transformers. These utilize the principle of electromagnetic induction and are primarily composed of components such as an iron core and copper wire windings, sealed with epoxy resin. Existing electromagnetic three-phase, five-pole voltage transformers suffer from significant drawbacks, including energy consumption, material consumables, and high costs. In particular, 6kV and 10kV electromagnetic three-phase, five-pole voltage transformers are large and heavy, making on-site installation, maintenance, and replacement inconvenient. Furthermore, the large size of existing electromagnetic three-phase, five-pole voltage transformers increases the manufacturing cost of their flameproof enclosures. Furthermore, these types of electromagnetic three-phase, five-pole voltage transformers are prone to core saturation, leaving room for improvement in operational safety and reliability. Summary of the Invention

[0004] The purpose of the present invention is to provide a three-phase five-column voltage transformer for coal mines based on resistance voltage division, so as to solve the problems of energy consumption, material consumption, high cost and the need to improve working safety and reliability of the existing electromagnetic three-phase five-column voltage transformer used in coal mines.

[0005] The technical solution of the present invention is as follows: the three-phase five-post coal mine voltage transformer based on resistance voltage division of the present invention comprises an insulating housing, a circuit device, and epoxy resin cast in the insulating housing. The circuit device comprises five terminals fixedly mounted on the insulating housing, namely, phase A, phase B, phase C, zero-sequence voltage, and neutral point, three high-voltage insulated input wires for introducing voltage signals from the outside into the insulating housing, and a circuit board fixedly mounted in the insulating housing. The structural features of the transformer are as follows: a DC power conversion module, a resistance voltage division module, an active filtering acquisition module, and an isolated output module are mounted on the circuit board; the active filtering acquisition module and the isolated output module are each provided with four identically structured terminals;

[0006] The above-mentioned DC power conversion module is provided with a power input terminal, a positive output terminal and a negative output terminal; the resistor voltage division module is provided with A-phase, B-phase and C-phase voltage input terminals, A-phase, B-phase and C-phase voltage output terminals, a zero-sequence voltage output terminal, a GND terminal and a ground terminal; the active filter acquisition module is provided with a voltage signal input terminal, a voltage signal output terminal, a VCC terminal and a GND terminal; the isolation output module is provided with a voltage signal input terminal, a voltage signal output terminal, a neutral point terminal and a GND terminal;

[0007] The A-phase, B-phase and C-phase voltage input terminals of the above-mentioned resistor voltage division module are each electrically connected to one end of an input high-voltage insulated wire. The voltage signal input terminals of the three active filter acquisition modules are respectively and correspondingly electrically connected to the A-phase, B-phase and C-phase voltage output terminals of the resistor voltage division module. The voltage signal input terminal of one active filter acquisition module is electrically connected to the zero-sequence voltage output terminal of the resistor voltage division module; the voltage signal input terminals of the four isolation output modules are respectively and correspondingly electrically connected to the voltage signal output terminals of the four active filter acquisition modules; the voltage signal output terminals of the four isolation output modules are respectively and correspondingly electrically connected to the A-phase, B-phase, C-phase and zero-sequence voltage terminals. The neutral point terminals of the four isolation output modules are all electrically connected to the neutral point terminal; the VCC terminals of the four active filter acquisition modules are all electrically connected to the positive output terminal of the DC power conversion module; the GND terminal of the resistor voltage division module, the GND terminals of the four active filter acquisition modules and the four isolation output modules are all electrically connected to the negative output terminal of the DC power conversion module; the ground terminal of the resistor voltage division module is grounded.

[0008] A further solution is that the above circuit device further includes two DC power input terminals fixedly arranged on the insulating housing; the above-mentioned DC power conversion module has a power input terminal, and the power input terminal of the DC power conversion module is electrically connected to the two DC power input terminals. During use, the DC power conversion module externally connects a DC power supply through the two DC power input terminals.

[0009] A further solution is that the above insulating housing is provided with mounting ears.

[0010] A further solution is as follows: The above resistor voltage division module includes a total of 8 resistors, namely R1 to R8. One end of each of the above resistors R1, R3, and R5 is the input terminal of the A-phase, B-phase, and C-phase voltages of the above resistor voltage division module; the other end of resistor R1 and one end of resistor R3 have a common connection point, and this common connection point is the output terminal of the A-phase voltage of the above resistor voltage division module; the other end of resistor R3 and one end of resistor R4 have a common connection point, and this common connection point is the output terminal of the B-phase voltage of the above resistor voltage division module; the other end of resistor R5 and one end of resistor R6 have a common connection point, and this common connection point is the output terminal of the C-phase voltage of the above resistor voltage division module 7; the other ends of resistors R2, R4, and R5 and one end of resistor R7 have a common connection point, and this common connection point is the GND terminal of the above resistor voltage division module; the other end of resistor R7 and one end of resistor R8 have a common connection point, and this common connection point is the output terminal of the zero-sequence voltage of the above resistor voltage division module; the other end of resistor R8 is the ground terminal of the above resistor voltage division module.

[0011] A further solution is as follows: The resistors R1 to R6 of the above resistor voltage division module are thick-film non-inductive high-voltage voltage division resistors with a power value in the W level and a resistance value in the MΩ level.

[0012] A further solution is as follows: The above active filter acquisition module includes a four-op amp integrated chip U, an inductor L1, a TVS diode D1, a total of 9 resistors, namely R9 to R17, and a total of 5 capacitors, namely C1 to C5; the above four-op amp integrated chip U has a total of 14 functional pins numbered 1 to 14.

[0013] One end of the above-mentioned inductor L1 and one end of the TVS diode D1 have a common connection point, which is the voltage signal input end of the above-mentioned active filter acquisition module; the other end of the inductor L1 is electrically connected to one end of the resistor R, and the other end of the resistor R is electrically connected to the pin 3 of the four-op-amp integrated chip U. The pin 4 of the four-op-amp integrated chip U and one end of the capacitor C1 have a common connection point, which is the VCC end of the above-mentioned active filter acquisition module; the pin 11 of the four-op-amp integrated chip U and one end of the capacitor C2 have a common connection point; the pin 2, pin 1 of the four-op-amp integrated chip U and one end of the resistor R10 have a common connection point. The other end of the resistor R10, one end of the capacitor C4 and one end of the resistor R11 have a common connection point. The other end of the resistor R11, one end of the capacitor C3 and the pin 5 of the four-op-amp integrated chip U have a common connection point. The pins 6 and 7 of the four-op-amp integrated chip U, the other end of the capacitor C4, one end of the capacitor C5 and one end of the resistor R13 have a common connection point. The other end of the capacitor C5, one end of the resistor R12 and the pin 10 of the four-op-amp integrated chip U have a common connection point. The other end of the resistor R13, one end of the resistor R14 and the pin 9 of the four-op-amp integrated chip U have a common connection point. The other end of the resistor R14, one end of the resistor R15 and the pin 8 of the four-op-amp integrated chip U have a common connection point. The other end of the resistor R15 is electrically connected to the pin 12 of the four-op-amp integrated chip U. The pin 13 of the four-op-amp integrated chip U, one end of the resistor R16 and one end of the resistor R17 have a common connection point. The other end of the resistor R17 and the pin 14 of the four-op-amp integrated chip U have a common connection point, which is the voltage signal output end of the above-mentioned active filter acquisition module; the other end of the TVS diode D1, the other ends of the capacitors C1 - C3, and the other ends of the resistors R12 and R16 together constitute the GND end of the above-mentioned active filter acquisition module.

[0014] A further solution is: the above-mentioned four-op-amp integrated chip U is a four-op-amp integrated chip of the LM324 model; the TVS diode D1 is a transient voltage suppression diode of the SMBJ12CA model.

[0015] A further solution is: the above-mentioned isolation output module includes a transformer T1. The primary side of the transformer T1 has connection terminals 1, 2, and 5. The secondary side of the transformer T1 has connection terminals 3 and 4. The connection terminal 1 of the transformer T1 is the voltage signal input end of the above-mentioned isolation output module. The connection terminal 3 of the transformer T1 is the voltage signal output end of the above-mentioned isolation output module. The connection terminal 4 of the transformer T1 is the neutral point end of the above-mentioned isolation output module. The connection terminal 2 of the transformer T1 is the GND end of the above-mentioned isolation output module. The connection terminal 5 of the transformer T1 is left unused.

[0016] The present invention has the following positive effects: (1) Through the structural design of the overall structure, especially the circuit device, the present invention is small in volume, light in weight, convenient for installation and replacement operations, has a relatively low material cost, consumes relatively less energy during operation, and the cost of a single device can be reduced by thousands of yuan compared with the existing electromagnetic three-phase five-column voltage transformer, thus effectively solving the technical problems of the existing electromagnetic three-phase five-column voltage transformer, such as large volume, heavy weight, high consumption of materials, high cost, and high energy consumption during use. (2) When in use, the present invention can be conveniently directly connected to the high- and low-voltage power grids in coal mines. During operation, it has a high impedance between phases and no ferromagnetic resonance, and the voltage transformer core saturation phenomenon that easily occurs in the existing electromagnetic three-phase five-column voltage transformer will not occur during overvoltage, so the installation reliability during operation is better than that of the existing technology. (3) The voltage-dividing resistors in the resistor voltage-dividing module of the circuit device of the present invention adopt thick-film non-inductive high-voltage voltage-dividing resistors with a power value of W level and a resistance value of MΩ level, with a maximum continuous operating voltage of 22 kV, which can withstand large-range voltage fluctuations on a 10 kV line and ensure long-term stable operation. (4) The active filter acquisition module in the circuit device of the present invention is connected in parallel with TVS diodes at the input end to protect the subsequent circuit from overvoltage impact; an active filter acquisition module with a high input impedance is used to collect, filter, condition, and output the voltage signal sent by the resistor voltage-dividing module, and then the output three-phase voltage and zero-sequence voltage are secondarily isolated through the isolation output module to generate the measurement and protection voltage signals required by the relay protection device, and the working safety and reliability are good, thus being able to improve the safety of the power supply system in the mine. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic external structure diagram of the present invention;

[0018] Figure 2 is Figure 1 the A-A sectional view, and for the convenience of expression, the epoxy resin cast in the insulating housing is omitted in the figure;

[0019] Figure 3 is a schematic block diagram of the structure of the circuit device of the present invention;

[0020] Figure 4 is Figure 2 the electrical schematic diagram of an implementation manner of the resistor voltage-dividing module in

[0021] Figure 5 is Figure 2 the electrical schematic diagram of an implementation manner of the active filter acquisition module in

[0022] Figure 6 is Figure 2 the electrical schematic diagram of an implementation manner of the isolation output module in

[0023] The reference numerals in the above-mentioned drawings are as follows:

[0024] Insulating housing 1, mounting ear 1-1, input high-voltage insulating wire 2, DC power input terminal 3, output terminal block group 4, circuit board 5, DC power conversion module 6, resistor voltage division module 7, active filter acquisition module 8, isolation output module 9. Specific implementation mode

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation modes.

[0026] (Embodiment 1)

[0027] See Figures 1 to 3 , the three-phase five-column type coal mine voltage transformer based on resistor voltage division in this embodiment mainly consists of an insulating housing 1, a circuit device, and epoxy resin for explosion-proof potting of the circuit device in the insulating housing 1. The circuit device includes 3 input high-voltage insulating wires 2 for introducing voltage signals into the insulating housing 1 from the outside, a DC power input terminal 3 (positive and negative terminals) and an output terminal block group 4 fixedly arranged on the insulating housing 1, and a circuit board 5 fixedly arranged in the insulating housing 1; the DC power input terminal 3 has a total of 2 positive and negative input terminals, and the output terminal block group 4 includes 5 terminal blocks, namely an A-phase terminal block, a B-phase terminal block, a C-phase terminal block, a zero-sequence voltage terminal block, and a neutral point terminal block. Preferably, the insulating housing 1 is also provided with a mounting ear 1-1 that is convenient for installation during use.

[0028] The circuit board 5 is provided with a DC power conversion module 6, a resistor voltage division module 7, an active filter acquisition module 8, and an isolation output module 9. Among them, the active filter acquisition module 8 and the isolation output module 9 are respectively provided with 4 with the same structure.

[0029] The DC power conversion module 6 has positive and negative input ends, a positive output end (VCC), and a negative output end (GND); the resistor voltage division module 7 has A-phase, B-phase, and C-phase voltage input ends, A-phase, B-phase, and C-phase voltage output ends, a zero-sequence voltage output end, a GND end, and a ground end (PE end); the active filter acquisition module 8 has a voltage signal input end, a voltage signal output end, a VCC end, and a GND end; the isolation output module 9 has a voltage signal input end, a voltage signal output end, a neutral point end, and a GND end.

[0030] The positive and negative input terminals of the DC power conversion module 6 are correspondingly electrically connected to the positive and negative input terminals of the DC power input terminal 3; the A-phase, B-phase, and C-phase voltage input terminals of the resistor voltage division module 7 are each electrically connected to one end of an input high-voltage insulating wire 2, and the voltage signal input terminals of the three active filter acquisition modules 8 are respectively correspondingly electrically connected to the A-phase, B-phase, and C-phase voltage output terminals of the resistor voltage division module 7, and the voltage signal input terminal of one active filter acquisition module 8 is electrically connected to the zero-sequence voltage output terminal of the resistor voltage division module 7; the voltage signal input terminals of the four isolation output modules 9 are respectively correspondingly electrically connected to the voltage signal output terminals of the four active filter acquisition modules 8; the voltage signal output terminals of the four isolation output modules 9 are respectively correspondingly electrically connected to the A-phase, B-phase, C-phase, and zero-sequence voltage terminals in the output terminal block group 4, and the neutral point terminals of the four isolation output modules 9 are all electrically connected to the neutral point terminal of the output terminal block group 4; the VCC terminals of the four active filter acquisition modules 8 are all electrically connected to the positive output terminal of the DC power conversion module 6; the GND terminals of the four active filter acquisition modules 8, the GND terminal of the resistor voltage division module 7, and the GND terminals of the four isolation output modules 9 are all electrically connected to the negative output terminal of the DC power conversion module 6; the ground terminals of the resistor voltage division module 7 and the ground terminals of the four isolation output modules 9 are all connected to the ground; when in use, the positive and negative input terminals of the DC power conversion module 6 are externally connected to a DC power supply through two DC power input terminals 3, and the other ends of the three input high-voltage insulating wires 2 are electrically connected to the A-phase, B-phase, and C-phase power supply terminals of the electrical equipment to be sampled and measured; the output terminal block group 4 is electrically connected to an electrical equipment that requires a sampled signal, such as a relay protection device in a coal mine underground.

[0031] When in use, the DC power conversion module 6 is used to convert the externally connected DC power supply into a DC power supply suitable for the operation of the active filter acquisition module 8. In this embodiment, the external power supply is a DC24V power supply, which is converted into a DC12V DC power supply by the DC power conversion module 6 for the operation of the source filter acquisition module 8. The DC power conversion module 6 is a circuit module based on a DC-DC conversion integrated chip (such as a chip of model WRE2412S). The DC power conversion module 6 is a mature existing technology, and its structure will not be described in detail.

[0032] The three-phase five-column type coal mine voltage transformer based on resistor voltage division in this embodiment, when in use, divides the AC high voltage such as 10 kV into low voltage signals required for measurement and protection by the coal mine underground relay protection device through the resistor voltage division module 7. The low voltage signal after voltage division by the resistor voltage division module 7 is sent to the active filter acquisition module 8 with a high input impedance, and after protection, acquisition, filtering, and conditioning, it is output to the isolation output module 9. The isolation output module 9 isolates and processes the three-phase voltage and zero-sequence voltage signals sent by the previous-stage active filter acquisition circuit 8 and then outputs them as the measurement and protection voltage signals required by the coal mine underground relay protection device, so as to be able to replace the existing electromagnetic three-phase five-column voltage transformer used in the mine, and effectively solve the problems of high energy consumption, high material consumption, and high cost of the existing electromagnetic three-phase five-column voltage transformer.

[0033] See Figure 4 , as a specific implementation manner of the aforementioned resistor voltage division module 7, the resistor voltage division module 7 is mainly composed of a total of 8 resistors R1 to R8. One end of each of the resistor R1, resistor R3, and resistor R5 is the A-phase, B-phase, and C-phase voltage input terminals of the aforementioned resistor voltage division module 7; the other end of the resistor R1 and one end of the resistor R3 have a common connection point, and this common connection point is the A-phase voltage output terminal of the aforementioned resistor voltage division module 7; the other end of the resistor R3 and one end of the resistor R4 have a common connection point, and this common connection point is the B-phase voltage output terminal of the aforementioned resistor voltage division module 7; the other end of the resistor R5 and one end of the resistor R6 have a common connection point, and this common connection point is the C-phase voltage output terminal of the aforementioned resistor voltage division module 7; the other ends of the resistor R2, resistor R4, resistor R5, and one end of the resistor R7 have a common connection point, and this common connection point is the GND terminal of the aforementioned resistor voltage division module 7; the other end of the resistor R7 and one end of the resistor R8 have a common connection point, and this common connection point is the zero-sequence voltage output terminal of the aforementioned resistor voltage division module 7; the other end of the resistor R8 is the ground terminal (PE terminal) of the aforementioned resistor voltage division module 7.

[0034] The voltage division resistors R1 to R6 of the resistor voltage division module 7 adopt thick-film non-inductive high-voltage division resistors, with a maximum continuous operating voltage of up to 22 kV, an accuracy of up to 0.5%, a resistor power value of the W level, and a resistor resistance value of the MΩ level.

[0035] See Figure 5 , as a specific implementation manner of the aforementioned active filter acquisition module 8, the active filter acquisition module 8 is mainly composed of a four-op amp integrated chip U, an inductor L1, a TVS diode D1, a total of 9 resistors R9 to R17, and a total of 5 capacitors C1 to C; In this embodiment, the four-op amp integrated chip U preferably adopts a four-op amp integrated circuit of the LM324 model, which has a total of 14 functional pins numbered 1 to 14 and has 4 operational amplifiers U1 to U4; the TVS diode D1 preferably adopts a transient voltage suppression diode of the SMBJ12CA model.

[0036] One end of the inductor L1 and one end of the TVS diode D1 have a common connection point, and this common connection point is the voltage signal input end of the aforementioned active filter acquisition module 8; the other end of the inductor L1 is electrically connected to one end of the resistor R, the other end of the resistor R is electrically connected to the pin 3 of the quad operational amplifier integrated chip U, the pin 4 of the quad operational amplifier integrated chip U and one end of the capacitor C1 have a common connection point, and this common connection point is the VCC end of the aforementioned active filter acquisition module 8; the pin 11 of the quad operational amplifier integrated chip U and one end of the capacitor C2 have a common connection point; the pin 2, pin 1 of the quad operational amplifier integrated chip U and one end of the resistor R10 have a common connection point, the other end of the resistor R10, one end of the capacitor C4 and one end of the resistor R11 have a common connection point, the other end of the resistor R11, one end of the capacitor C3 and the pin 5 of the quad operational amplifier integrated chip U have a common connection point, the pins 6 and 7 of the quad operational amplifier integrated chip U, the other end of the capacitor C4, one end of the capacitor C5 and one end of the resistor R13 have a common connection point, the other end of the capacitor C5, one end of the resistor R12 and the pin 10 of the quad operational amplifier integrated chip U have a common connection point, the other end of the resistor R13, one end of the resistor R14 and the pin 9 of the quad operational amplifier integrated chip U have a common connection point, the other end of the resistor R14, one end of the resistor R15 and the pin 8 of the quad operational amplifier integrated chip U have a common connection point, the other end of the resistor R15 is electrically connected to the pin 12 of the quad operational amplifier integrated chip U, the pin 13 of the quad operational amplifier integrated chip U, one end of the resistor R16 and one end of the resistor R17 have a common connection point, the other end of the resistor R17 and the pin 14 of the quad operational amplifier integrated chip U have a common connection point, and this common connection point is the voltage signal output end of the aforementioned active filter acquisition module 8; the other end of the TVS diode D1, the other ends of the capacitors C1 - C3, and the other ends of the resistors R12 and R16 together constitute the GND end of the aforementioned active filter acquisition module 8.

[0037] Functionally, the active filter acquisition module 8 can be divided into four parts: input, filtering, phase shifting, and output. When working, the inductor L1 is used to suppress high-frequency interference, and the TVS diode D1 is used to protect the subsequent circuit. The active filter acquisition module 8 adopts a high-impedance input and only needs to draw an extremely small current from the previous circuit. The drawn current level is in the μA level, avoiding the influence of the voltage acquisition circuit on the previous resistor voltage division module 7. The low voltage sent by the resistor voltage division module 7 is sent to the second-order low-pass filter unit through a follower circuit. The filter circuit filters out the high-order harmonics in the signal to form a voltage that meets the input requirements. Since both the filter and the subsequent isolation output module 9 cause a certain lag in the phase of the signal voltage, in order to offset this influence, the phase shifting circuit shifts the phase of the signal voltage forward without changing the voltage amplitude. The output part has two functions. One is to amplify and output the signal voltage so that the output voltage changes strictly in proportion to the amplitude of the grid voltage and meets the rated output standard of the electronic current transformer. The other is to use a follower circuit to improve the load-carrying capacity and drive the isolation output module 9 to obtain a signal voltage that meets the requirements on the secondary side of the isolation output module 9.

[0038] See Figure 6 , as a specific implementation manner of the foregoing isolation output module 9, the isolation output module 9 is mainly composed of a transformer T1. The primary side of the transformer T1 has connection terminals 1, 2, and 5, and the secondary side of the transformer T1 has connection terminals 3 and 4. The connection terminal 1 of the transformer T1 is the voltage signal input terminal of the foregoing isolation output module 9, the connection terminal 3 of the transformer T1 is the voltage signal output terminal of the foregoing isolation output module 9, the connection terminal 4 of the transformer T1 is the neutral point terminal of the foregoing isolation output module 9, the connection terminal 2 of the transformer T1 is the GND terminal of the foregoing isolation output module 9, and the connection terminal 5 of the transformer T1 is left unused. The isolation output module 9 can achieve safe isolation between input and output, and the accuracy level reaches 0.1%.

[0039] The three-phase five-column type coal mine voltage transformer based on resistor voltage division in this embodiment has a small volume, light weight, convenient installation and replacement operations, and low material costs through the overall structure and circuit design; when in use, it can be conveniently and directly connected to the high- and low-voltage power grids in coal mines. During operation, it has a high impedance between phases and no ferromagnetic resonance. When overvoltage occurs, it will not have the phenomenon of core saturation of the voltage transformer that easily appears in the existing electromagnetic three-phase five-column voltage transformer, and can improve the safety of the power supply system in the mine.

[0040] The above embodiments are descriptions of the specific implementation manners of the present invention, rather than limitations on the present invention. Those skilled in the relevant technical fields can also make various transformations and changes to obtain corresponding equivalent technical solutions without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should be included in the patent protection scope of the present invention.

Claims

1. A three-phase five-column type coal mine voltage transformer based on resistor voltage division, comprising an insulating housing, a circuit device, and epoxy resin encapsulated in the insulating housing. The circuit device includes five terminal posts, namely, phase A, phase B, phase C, zero-sequence voltage, and neutral point, fixedly arranged on the insulating housing, three input high-voltage insulating wires for introducing voltage signals into the insulating housing from the outside, and a circuit board fixedly arranged in the insulating housing, and is characterized in that: A DC power conversion module, a resistor voltage division module, an active filter acquisition module, and an isolation output module are provided on the circuit board; there are 4 active filter acquisition modules and isolation output modules with the same structure respectively; The DC power conversion module is provided with a power input terminal, a positive output terminal, and a negative output terminal; the resistor voltage division module is provided with A-phase, B-phase, and C-phase voltage input terminals, A-phase, B-phase, and C-phase voltage output terminals, a zero-sequence voltage output terminal, a GND terminal, and a ground terminal; the active filter acquisition module is provided with a voltage signal input terminal, a voltage signal output terminal, a VCC terminal, and a GND terminal; the isolation output module is provided with a voltage signal input terminal, a voltage signal output terminal, a neutral point terminal, and a GND terminal; One end of each of the A-phase, B-phase, and C-phase voltage input terminals of the resistor voltage division module is electrically connected to one end of an input high-voltage insulated wire. The voltage signal input terminals of 3 active filter acquisition modules are respectively and correspondingly electrically connected to the A-phase, B-phase, and C-phase voltage output terminals of the resistor voltage division module. The voltage signal input terminal of 1 active filter acquisition module is electrically connected to the zero-sequence voltage output terminal of the resistor voltage division module. The voltage signal input terminals of 4 isolation output modules are respectively and correspondingly electrically connected to the voltage signal output terminals of 4 active filter acquisition modules. The voltage signal output terminals of 4 isolation output modules are respectively and correspondingly electrically connected to the A-phase, B-phase, C-phase, and zero-sequence voltage terminals. The neutral point terminals of 4 isolation output modules are all electrically connected to the neutral point terminal. The VCC terminals of 4 active filter acquisition modules are all electrically connected to the positive output terminal of the DC power conversion module. The GND terminal of the resistor voltage division module, the GND terminals of 4 active filter acquisition modules and 4 isolation output modules are all electrically connected to the negative output terminal of the DC power conversion module. The ground terminal of the resistor voltage division module is connected to the ground; The resistor voltage division module includes a total of 8 resistors R1 to R8. One end of each of the resistors R1, R3, and R5 is the A-phase, B-phase, and C-phase voltage input terminals of the resistor voltage division module. The other end of the resistor R1 and one end of the resistor R3 have a common connection point, and this common connection point is the A-phase voltage output terminal of the resistor voltage division module. The other end of the resistor R3 and one end of the resistor R4 have a common connection point, and this common connection point is the B-phase voltage output terminal of the resistor voltage division module. The other end of the resistor R5 and one end of the resistor R6 have a common connection point, and this common connection point is the C-phase voltage output terminal of the resistor voltage division module 7. The other ends of the resistors R2, R4, and R5 and one end of the resistor R7 have a common connection point, and this common connection point is the GND terminal of the resistor voltage division module. The other end of the resistor R7 and one end of the resistor R8 have a common connection point, and this common connection point is the zero-sequence voltage output terminal of the resistor voltage division module. The other end of the resistor R8 is the ground terminal of the resistor voltage division module; The resistors R1 to R6 of the resistor voltage division module are thick-film non-inductive high-voltage voltage division resistors with a power value of the W level and a resistance value of the MΩ level; The circuit device further includes two DC power input terminals fixedly arranged on the insulating housing; the DC power conversion module has a power input end, and the power input end of the DC power conversion module is electrically connected to the two DC power input terminals. During use, the DC power conversion module externally connects a DC power supply through the two DC power input terminals; Mounting ears are provided on the insulating housing.

2. The three-phase five-column type coal mine voltage transformer based on resistance voltage division according to claim 1, wherein: The active filter acquisition module includes a quad operational amplifier integrated chip U, an inductor L1, a TVS diode D1, nine resistors R9 to R17 in total, and five capacitors C1 to C5 in total; the quad operational amplifier integrated chip U has 14 functional pins numbered 1 to 14; One end of the inductor L1 and one end of the TVS diode D1 have a common connection point, and this common connection point is the voltage signal input end of the active filter acquisition module; the other end of the inductor L1 is electrically connected to one end of the resistor R, the other end of the resistor R is electrically connected to the 3rd pin of the quad operational amplifier integrated chip U, and the 4th pin of the quad operational amplifier integrated chip U and one end of the capacitor C1 have a common connection point, and this common connection point is the VCC end of the active filter acquisition module; The 11th pin of the quad operational amplifier integrated chip U and one end of the capacitor C2 have a common connection point; the 2nd pin, the 1st pin of the quad operational amplifier integrated chip U, and one end of the resistor R10 have a common connection point, the other end of the resistor R10, one end of the capacitor C4, and one end of the resistor R11 have a common connection point, the other end of the resistor R11, one end of the capacitor C3, and the 5th pin of the quad operational amplifier integrated chip U have a common connection point, the 6th and 7th pins of the quad operational amplifier integrated chip U, the other end of the capacitor C4, one end of the capacitor C5, and one end of the resistor R13 have a common connection point, the other end of the capacitor C5, one end of the resistor R12, and the 10th pin of the quad operational amplifier integrated chip U have a common connection point, the other end of the resistor R13, one end of the resistor R14, and the 9th pin of the quad operational amplifier integrated chip U have a common connection point, the other end of the resistor R14, one end of the resistor R15, and the 8th pin of the quad operational amplifier integrated chip U have a common connection point, the other end of the resistor R15 is electrically connected to the 12th pin of the quad operational amplifier integrated chip U, the 13th pin of the quad operational amplifier integrated chip U, one end of the resistors R16 and R17 have a common connection point, and the other end of the resistor R17 and the 14th pin of the quad operational amplifier integrated chip U have a common connection point, and this common connection point is the voltage signal output end of the active filter acquisition module; the other end of the TVS diode D1, the other ends of the capacitors C1 to C3, and the other ends of the resistors R12 and R16 together constitute the GND end of the active filter acquisition module.

3. The three-phase five-column type coal mine voltage transformer based on resistor voltage division according to claim 2, wherein: The quad operational amplifier integrated chip U is a quad operational amplifier integrated chip of the LM324 model; the TVS diode D1 is a transient voltage suppression diode of the SMBJ12CA model.

4. The three-phase five-column type coal mine voltage transformer based on resistor voltage division according to claim 1, wherein: The isolation output module includes a transformer T1. The primary side of the transformer T1 has terminals 1, 2, and 5, and the secondary side of the transformer T1 has terminals 3 and 4. The terminal 1 of the transformer T1 is the voltage signal input terminal of the isolation output module, the terminal 3 of the transformer T1 is the voltage signal output terminal of the isolation output module, the terminal 4 of the transformer T1 is the neutral point terminal of the isolation output module, the terminal 2 of the transformer T1 is the GND terminal of the isolation output module, and the terminal 5 of the transformer T1 is left unused.

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