Multi-stage combined voltage transformer

Abstract

The invention discloses a multi-stage combined voltage transformer, which belongs to the technical field of combination of transformers, and comprises a box body, a sealed space is formed in the box body, and an oil passing nozzle is arranged on the vertical side wall of the box body; and the iron core is in a five-column shape, and the iron core is accommodated in the sealed space. Through the arrangement of the iron core, the primary winding, the secondary voltage winding, the secondary current winding and the wire connector, a secondary voltage induction coil and a secondary current induction coil can be combined on one iron core, the structure is compact, and meanwhile, the structure is compact. The number of turns of the secondary voltage winding and the secondary current winding can be changed through the voltage end relay set and the current end relay set, and the device is suitable for measuring instruments with different measuring ranges and power systems with different loads.

Description

Technical Field

[0001] The invention belongs to the technical field of mutual inductor combination, and in particular relates to a multi-stage combined voltage mutual inductor. Background Art

[0002] Combined voltage transformers integrate voltage and current transformer functions in a compact, typically fully enclosed, cast-in-place design. They offer strong protection and are suitable for indoor use. Based on the principle of electromagnetic induction, they convert high voltage and high current proportionally, enabling simultaneous voltage and current measurement. This supports power system monitoring and protection, and they are easy to install and offer strong anti-interference capabilities.

[0003] The existing Chinese invention patent with publication number CN102832035A discloses a combined voltage transformer, which is connected and used in combination with a voltage transformer and a current transformer. The present invention is small in size and has a reasonable layout; it is easy to install and saves manufacturing and maintenance costs. However, in actual use, due to design deficiencies, single function and fixed range, the transformer has poor applicability to power systems and measuring instruments of different ranges during use. In view of this, a multi-stage combined voltage transformer is provided. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the disadvantages of the above-mentioned prior art and provide a multi-stage combined voltage transformer.

[0005] The technical solutions adopted to solve the above technical problems are: A multi-stage combined voltage transformer, comprising: A box body, wherein the interior of the box body forms a sealed space, and a vertical side wall of the box body is provided with an oil nozzle; An iron core, wherein the iron core adopts a five-column shape and is placed in a sealed space; A primary winding, wherein three primary windings are provided and wound around the outside of three upright posts in the center of the iron core; The secondary voltage winding is provided with three and is sleeved on the outside of the column above the primary winding, including voltage winding 1, voltage winding 2 and voltage winding 3. The two ends of the voltage winding 1, voltage winding 2 and voltage winding 3 are respectively provided with voltage connection posts 1, voltage connection posts 2 and voltage connection posts 3; The secondary current winding is provided with three and is sleeved on the outside of the column below the primary winding, including current winding 1, current winding 2 and current winding 3. The two ends of the current winding 1, current winding 2 and current winding 3 are respectively provided with current connecting posts 1, current connecting posts 2 and current connecting posts 3; The connector includes a voltage terminal 1 and a voltage terminal 2, as well as a current terminal 1 and a current terminal 2. The voltage terminal 1 and the voltage terminal 2 are electrically connected to the voltage winding 1, the voltage winding 2 and the voltage winding 3 through a voltage terminal relay group, and the current terminal 1 and the current terminal 2 are electrically connected to the current winding 1, the current winding 2 and the current winding 3 through a current terminal relay group.

[0006] Among them, the primary winding is connected to the circuit. When high-voltage current is introduced into the primary winding, it is immersed in the protective oil inside the box to cool down. Based on electromagnetic induction, at the secondary voltage winding position, the number of turns of the primary winding is much larger than the number of turns of the secondary voltage winding. The high voltage is proportionally reduced to a low voltage through a high turns ratio. At the secondary current winding position, the number of turns of the primary winding is much smaller than the number of turns of the secondary current winding. The large current is reduced to a small current through electromagnetic induction. By connecting the measuring equipment between voltage terminal one and voltage terminal two, or between current terminal one and current terminal two, the proportionally reduced voltage and current can be measured, ensuring accurate measurement of voltage and current and protecting the safe use of equipment. At the connector position, the voltage-end relay group can connect voltage winding one, voltage winding two and voltage winding three with the measuring equipment in combination. Similarly, the current-end relay group can connect current winding one, current winding two and current winding three with the measuring equipment in combination. It can adapt to measuring equipment of different ranges and circuit systems with different loads, and is highly practical.

[0007] Furthermore, the voltage end relay group includes voltage end relay one, voltage end relay two, voltage end relay three, voltage end relay four and voltage end relay five, the voltage connection pole one at one end of the voltage winding one is electrically connected to the voltage terminal one, the voltage connection pole one at the other end of the voltage winding one is connected in parallel with voltage end relay one and voltage end relay two, the voltage connection pole two at one end of the voltage winding two is electrically connected to the voltage end relay one, the voltage connection pole two at the other end of the voltage winding two is connected in parallel with voltage end relay three and voltage end relay four, the voltage connection pole three at one end of the voltage winding three is electrically connected to the voltage end relay three, the voltage connection pole three at the other end of the voltage winding three is connected in series with the voltage end relay five, and the voltage end relay two, voltage end relay four and voltage end relay five are connected in parallel at the two ends of the voltage terminal.

[0008] Through the above technical solution, the specific configuration of the voltage-end relay group is disclosed, which can form three combinations of voltage winding one, voltage winding one and voltage winding two, or voltage winding one, voltage winding two and voltage winding three, thereby changing the total number of turns of the secondary voltage winding and thus changing the magnitude of the generated induced voltage.

[0009] Furthermore, the current end relay group includes current end relay one, current end relay two, current end relay three, current end relay four and current end relay five, the current connecting pole one at one end of the current winding one is electrically connected to the current terminal one, the current connecting pole one at the other end of the current winding one is connected in parallel with current end relay one and current end relay two, the current connecting pole two at one end of the current winding two is electrically connected to the current end relay one, the current connecting pole two at the other end of the current winding two is connected in parallel with current end relay three and current end relay four, the current connecting pole three at one end of the current winding three is electrically connected to the current end relay three, the current connecting pole three at the other end of the current winding three is connected in series with the current end relay five, and the current end relay two, current end relay four and current end relay five are connected in parallel at the two ends of the current terminal.

[0010] Through the above technical solution, the specific configuration of the current-end relay group is disclosed, which can form three combinations of current winding one, current winding one and current winding two, or current winding one, current winding two and current winding three, thereby changing the total number of turns of the secondary current winding and thus changing the magnitude of the generated induced current.

[0011] Furthermore, voltage sub-wires are respectively provided at both ends of the voltage winding one, voltage winding two and voltage winding three, and the three voltage sub-wires located on the same side are combined to form a voltage winding harness. The secondary voltage winding is provided with two voltage winding harnesses in total.

[0012] Through the above technical solution, voltage sub-wires are led out from both ends of voltage winding one, voltage winding two and voltage winding three respectively, and are wrapped with outer skin to form a voltage winding harness, which is not easy to break after integration. When led out to the connector, they are connected again to equally spaced voltage connecting poles one, voltage connecting poles two and voltage connecting poles three, which facilitates wiring operations.

[0013] Furthermore, current sub-wires are respectively provided at both ends of the current winding one, current winding two and current winding three, and the three current sub-wires located on the same side are combined to form a current winding bundle. The secondary current winding is provided with two current winding bundles in total.

[0014] Through the above technical solution, current sub-wires are led out from both ends of current winding one, current winding two and current winding three respectively, and are wrapped by outer skin to form a current winding harness, which is not easy to break after integration. When led out to the connector, they are connected again to the current connecting poles one, current connecting poles two and current connecting poles three that are arranged equidistantly, which facilitates wiring operations.

[0015] Furthermore, the box body is equipped with a built-in zero-sequence winding, which is wound around the outside of the column at the outermost edge of the iron core, and zero-sequence connection columns are provided at both ends of the zero-sequence winding.

[0016] Through the above technical solution, the zero-sequence winding can be used in a three-phase circuit. Under normal circumstances, the vector sum of the three-phase currents is zero; however, when a single-phase grounding fault occurs, the vector sum of the three-phase currents is no longer zero, and a zero-sequence current is generated at the zero-sequence winding position. By inducing the magnetic flux change of the zero-sequence current, an induced electrical signal is generated in the zero-sequence winding, so as to perform single-phase grounding fault detection and improve the applicability of the equipment.

[0017] Furthermore, the connector also includes a shell, which is fixed to the outer wall of the top of the box body, and the zero-sequence connecting post is arranged on the inner side of the shell.

[0018] Through the above technical solution, the shell has a top cover, which can be opened to expose the internal zero-sequence connection post, voltage terminal 1 and voltage terminal 2, as well as current terminal 1 and current terminal 2, so that users can connect to the measuring equipment through the data cable to detect the line.

[0019] Furthermore, the connector also includes a communication controller, which is connected in series between two zero-sequence connecting posts, between voltage terminal 1 and voltage terminal 2, and between current terminal 1 and current terminal 2 through a wiring harness.

[0020] Through the above technical solution, the communication controller has built-in measuring instruments, execution circuit boards and remote communication equipment, which can detect the detection voltage between the two zero-sequence connection poles, and can measure the induced voltage and induced current generated between voltage terminal one and voltage terminal two, and between current terminal one and current terminal two. Through the remote communication equipment, a control signal can be sent to the execution circuit board to control the on and off of the voltage end relay group and the current end relay group, remotely change the number of turns of the secondary voltage winding and the secondary current winding, and thus adapt to different measurement ranges and circuit systems more quickly.

[0021] Furthermore, the primary winding includes an insulating sleeve, which completely wraps the coil of the primary winding; the secondary voltage winding includes a voltage isolating sleeve, which completely wraps voltage winding one, voltage winding two and voltage winding three; the secondary current winding includes a current isolating sleeve, which completely wraps current winding one, current winding two and current winding three; and the zero-sequence winding, primary winding, secondary voltage winding and secondary current winding are covered with a cover on their outer sides.

[0022] Through the above technical solution, the insulating sleeve has insulation ability, which can avoid the voltage in the primary winding being too high and the breakdown fault between the iron core. The voltage isolation sleeve and the current isolation sleeve can provide insulation protection between the primary winding, further improving the anti-breakdown capability. In addition, the cover increases the contact area with the protective oil inside the box to provide protection and cooling, thereby helping to reduce abnormal breakdown and short circuit caused by high temperature in the insulating sleeve, voltage isolation sleeve and current isolation sleeve.

[0023] Furthermore, the iron core includes a main body arranged in a stacked manner, and the top and bottom ends of the main body are clamped and squeezed by two pressing plates, and a pressing piece is connected between the two pressing plates.

[0024] Through the above technical solution, the main body is composed of multiple stacked metal sheets. The metal sheet core is made of thin and insulating silicon steel sheets. An insulating layer is coated between each sheet to reduce eddy current heating. The structural design of the metal sheet core makes its heat dissipation area larger, which can effectively reduce the operating temperature. The pressure plate is pressed together by a detachable clamping part. The overall structure is stable. When the insulation layer is damaged due to heat, it can also be quickly disassembled for replacement and maintenance, and the later maintenance cost is low.

[0025] The beneficial effects of the present invention are as follows: (1) The present invention can combine a secondary voltage induction coil and a secondary current induction coil on a single iron core by arranging an iron core, a primary winding, a secondary voltage winding, a secondary current winding, and a connector. The structure is compact. At the same time, the number of turns of the secondary voltage winding and the secondary current winding can be changed by a voltage-end relay group and a current-end relay group, thereby adapting to measuring instruments of different ranges and power systems of different loads. (2) The present invention uses the design of a connector to quickly combine the coaxially wound secondary voltage winding and the secondary current winding, change the on / off state of different relays, and quickly change the combination mode to adapt to the load changes of the circuit system. When the circuit system is abnormal, remote control can reduce the induced voltage and induced current to a minimum, thereby minimizing the damage to the transformer caused by abnormal fluctuations. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the overall structural diagram of the present invention; Figure 2 This is a schematic diagram of the structure of the present invention when the box is removed. Figure 1 ; Figure 3 This is a schematic diagram of the structure of the present invention when the box is removed. Figure 2 ; Figure 4 It is a structural diagram of the iron core, primary winding, secondary voltage winding, secondary current winding and zero-sequence winding of the present invention; Figure 5 It is a structural schematic diagram of the secondary voltage winding of the present invention; Figure 6 It is a structural schematic diagram of the secondary current winding of the present invention; Figure 7 It is a structural diagram of the secondary voltage winding, the secondary current winding, the zero-sequence winding and the connector of the present invention; Figure 8It is a schematic diagram of the structure between the voltage winding harness, the voltage terminal 1 and the voltage terminal 2 of the present invention; Figure 9 It is a schematic structural diagram of the current winding harness, the current terminal 1 and the current terminal 2 of the present invention; Figure 10 It is a structural diagram between the housing and the communication controller of the present invention.

[0027] Figures: 1, box; 11, perspective window; 12, oil nozzle; 13, base; 2, iron core; 21, main body; 22, pressure plate; 23, pressing piece; 3, secondary voltage winding; 31, voltage winding one; 32, voltage winding two; 33, voltage winding three; 34, voltage sub-line; 35, voltage winding harness; 36, voltage isolating sleeve; 37, voltage connecting post one; 38, voltage connecting post two; 39, voltage connecting post three; 4, secondary current winding; 41, current winding one; 42, current winding two; 43, current winding three; 44, current sub-line; 45, current winding harness; 46, current isolating sleeve; 47, current connecting post one; 48, current connecting post two; 4 9. Current terminal three; 5. Primary winding; 51. Insulation sleeve; 52. Primary winding harness; 6. Connector; 61. Housing; 62. Voltage terminal one; 63. Voltage terminal two; 631. Voltage terminal relay one; 632. Voltage terminal relay two; 633. Voltage terminal relay three; 634. Voltage terminal relay four; 635. Voltage terminal relay five; 64. Current terminal one; 65. Current terminal two; 651. Current terminal relay one; 652. Current terminal relay two; 653. Current terminal relay three; 654. Current terminal relay four; 655. Current terminal relay five; 66. Communication controller; 7. Zero-sequence winding; 71. Zero-sequence terminal; 8. Cover. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] like Figures 1-10 As shown, this embodiment provides a multi-stage combined voltage transformer. To address the practical problems of the existing transformers with single functions and fixed ranges, a specific configuration is disclosed: For box 1, refer to Figure 1 and Figure 2 The interior of the box body 1 forms a sealed space. The vertical side wall of the box body 1 is provided with two oil nozzles 12, one high and one low, which can fill the box body 1 with protective oil. A transparent window 11 is designed to penetrate the liquid level of the protective oil. A base 13 is installed at the bottom of the box body 1 for supporting the iron core 2 installed inside the box body 1. For core 2, refer to Figure 2 The iron core 2 adopts a five-column shape, and the iron core 2 is placed in a sealed space, that is, installed above the base 13. The base 13 is made of insulating material to prevent the box 1 from being charged; Regarding the primary winding 5, refer to Figure 3 The primary winding 5 is provided with three and is wound around the outside of the three columns in the center of the iron core 2. The column end is connected to the top through the primary winding harness 52 so as to be connected to the circuit system through a wire. The column end has a multi-layer insulation string to prevent the box 1 from being charged. When used on the ground, it protects the safety of people passing by or accidentally touching the box 1. Regarding the secondary voltage winding 3, refer to FIG. Figure 3 and Figure 5 The secondary voltage winding 3 is provided with three windings and is arranged on the outside of the column above the primary winding 5. It can generate an induced voltage, including a voltage winding 1 31, a voltage winding 2 32, and a voltage winding 33 with gradually increasing numbers of turns. For example, the number of turns of the voltage winding 1 31 is equal to one-half of the voltage winding 2 32, and the number of turns of the voltage winding 2 32 is equal to one-quarter of the voltage winding 33. This design can increase the range of detectable voltage values. The two ends of the voltage winding 1 31, the voltage winding 2 32, and the voltage winding 33 are respectively provided with a voltage connection post 1 37, a voltage connection post 2 38, and a voltage connection post 39 for connecting to the connector 6; Regarding the secondary current winding 4, refer to Figure 4 and Figure 6 The secondary current winding 4 has three windings and is arranged on the outside of the column below the primary winding 5. It can generate an induced current and includes a current winding 1 41, a current winding 2 42, and a current winding 3 43 with gradually increasing numbers of turns. The ends of the current winding 1 41, the current winding 2 42, and the current winding 3 43 are respectively provided with a current connection post 1 47, a current connection post 2 48, and a current connection post 3 49 for connecting to the connector 6; For connector 6, refer to Figure 8 and Figure 9The connector 6 includes a voltage terminal 1 62 and a voltage terminal 2 63, which are used to connect to a voltage measuring instrument to output an induced voltage value, and a current terminal 1 64 and a current terminal 2 65, which are used to connect to a current measuring instrument to output an induced current value. Among them, the voltage terminal 1 62 and the voltage terminal 2 63 are electrically connected to the voltage winding 1 31, the voltage winding 2 32, and the voltage winding 3 33 through a voltage terminal relay group. The voltage terminal relay group can change the series connection mode of the voltage winding 1 31, the voltage winding 2 32, and the voltage winding 3 33. The current terminal 1 64 and the current terminal 2 65 are electrically connected to the current winding 1 41, the current winding 2 42, and the current winding 3 43 through a current terminal relay group. The current terminal relay group can change the series connection mode of the current winding 1 41, the current winding 2 42, and the current winding 3 43.

[0030] The working principle of this embodiment is as follows: The primary winding 5 is connected to the circuit. When high-voltage current is introduced into the primary winding 5, it is immersed in the protective oil inside the housing 1 to cool it down. Based on electromagnetic induction, at the position of the secondary voltage winding 3, the number of turns of the primary winding 5 is much larger than that of the secondary voltage winding 3. The high voltage is proportionally reduced to a low voltage through a high turns ratio. At the position of the secondary current winding 4, the number of turns of the primary winding 5 is much smaller than that of the secondary current winding 4. The high current is reduced to a low current through electromagnetic induction. By connecting the measuring device between the voltage terminal 1 62 and the voltage terminal 2 63, or between the current terminal 1 64 and the current terminal 2 65, the proportionally reduced voltage and current can be measured, ensuring accurate measurement of the voltage and current and protecting the safe use of the equipment. The measuring instrument is connected between the voltage terminal 1 62 and the voltage terminal 2 63, and between the current terminal 1 64 and the current terminal 2 65 at the position of the connector 6. The voltage terminal relay group can connect the voltage winding 1 31, the voltage winding 2 32 and the voltage winding 3 33 to the measuring equipment combination. Similarly, the current terminal relay group can connect the current winding 1 41, the current winding 2 42 and the current winding 3 43 to the measuring equipment combination. When a small-range measuring device is connected or the power system load is large, the number of turns of the secondary voltage winding 3 can be reduced and the number of turns of the secondary current winding 4 can be increased to reduce the values ​​of the induced voltage and the induced current for accurate detection. When a large-range measuring device is connected or the circuit system load is small, the number of turns of the secondary voltage winding 3 can be increased and the number of turns of the secondary current winding 4 can be reduced to increase the values ​​of the induced voltage and the induced current, thereby improving the measurement range. It can adapt to measuring devices of different ranges and circuit systems with different loads, and is highly practical.

[0031] In a further embodiment, the specific configuration of the voltage terminal relay group is disclosed, referring to Figure 8The voltage-end relay group includes a voltage-end relay 1 631, a voltage-end relay 2 632, a voltage-end relay 3 633, a voltage-end relay 4 634, and a voltage-end relay 5 635. The voltage connecting post 1 37 at one end of the voltage winding 1 31 is electrically connected to the voltage terminal 1 62. The voltage connecting post 1 37 at the other end of the voltage winding 1 31 is connected in parallel with the voltage-end relay 1 631 and the voltage-end relay 2 632. The voltage connecting post 2 38 at one end of the voltage winding 2 32 is electrically connected to the voltage-end relay 1 631. The voltage connecting post 2 38 at the other end of the voltage winding 2 32 is connected in parallel with the voltage-end relay 3 633 and the voltage-end relay 4 634. The voltage connecting post 3 39 at one end of the voltage winding 33 is electrically connected to the voltage-end relay 3 633. The other end of the voltage winding 33 The voltage terminal three 39 is connected in series with the voltage terminal relay five 635, and the voltage terminal relay two 632, the voltage terminal relay four 634 and the voltage terminal relay five 635 are connected in parallel at the end of the voltage terminal two 63. Specifically, the voltage winding one 31 can be formed to be connected alone between the voltage terminal one 62 and the voltage terminal two 63. At this time, the number of turns of the secondary voltage winding 3 participating in the induction of voltage is the least. When the voltage winding one 31 and the voltage winding two 32 are connected between the voltage terminal one 62 and the voltage terminal two 63, the number of turns of the secondary voltage winding 3 can be increased, or the voltage winding one 31, the voltage winding two 32 and the voltage winding three 33 are connected between the voltage terminal one 62 and the voltage terminal two 63 to maximize the number of turns of the secondary voltage winding 3, and then the size of the induced voltage generated is changed by changing the number of turns.

[0032] In a further embodiment, the specific configuration of the current terminal relay group is disclosed, referring to Figure 9The current end relay group includes a current end relay 1 651, a current end relay 2 652, a current end relay 3 653, a current end relay 4 654, and a current end relay 5 655. The current connecting post 1 47 at one end of the current winding 1 41 is electrically connected to the current terminal 1 64. The current connecting post 1 47 at the other end of the current winding 1 41 is connected in parallel with the current end relay 1 651 and the current end relay 2 652. The current connecting post 2 48 at one end of the current winding 2 42 is electrically connected to the current end relay 1 651. The current connecting post 2 48 at the other end of the current winding 2 42 is connected in parallel with the current end relay 3 653 and the current end relay 4 654. The current connecting post 3 49 at one end of the current winding 3 43 is electrically connected to the current end relay 3 653. The other end of the current winding 3 43 The current terminal three 49 is connected in series with the current terminal relay five 655, and the current terminal relay two 652, the current terminal relay four 654 and the current terminal relay five 655 are connected in parallel at the end of the current terminal two 65. Specifically, the current winding one 41 can be formed to be connected alone between the current terminal one 64 and the current terminal two 65. At this time, the number of turns of the secondary current winding 4 participating in the induction of current is the least. When the current winding one 41 and the current winding two 42 are connected between the current terminal one 64 and the current terminal two 65, the number of turns of the secondary current winding 4 can be increased, or the current winding one 41, the current winding two 42 and the current winding three 43 are connected between the current terminal one 64 and the current terminal two 65 to maximize the number of turns of the secondary current winding 4, and then the size of the induced current generated can be changed by changing the number of turns.

[0033] In a further embodiment, referring to Figure 5 , voltage winding 1 31, voltage winding 2 32 and voltage winding 3 3 are respectively provided with voltage sub-wires 34 at both ends, and the three voltage sub-wires 34 on the same side are combined to form a voltage winding harness 35, and voltage winding 1 31, voltage winding 2 32 and voltage winding 3 3 are respectively led out from both ends of voltage winding 31, voltage winding 2 32 and voltage winding 3 33, and are wrapped by outer skin to form a voltage winding harness 35, which is not easy to break after integration. The secondary voltage winding 3 is provided with two voltage winding harnesses 35, which are led out to the connector 6 and are respectively connected to the equally spaced voltage connecting posts 1 37, voltage connecting posts 2 38 and voltage connecting posts 39 to facilitate wiring operations.

[0034] In a further embodiment, referring to Figure 6, current winding 1 41, current winding 2 42 and current winding 3 43 are respectively provided with current sub-wires 44 at both ends. The three current sub-wires 44 on the same side are combined to form a current winding harness 45. Current sub-wires 44 are respectively led out from both ends of current winding 1 41, current winding 2 42 and current winding 3 43, and are wrapped by outer skin to form a current winding harness 45. After integration, it is not easy to break. The secondary current winding 4 is provided with two current winding harnesses 45. When led out to the connector 6, they are respectively connected to the current connecting post 1 47, current connecting post 2 48 and current connecting post 3 49 arranged at equal distances, which facilitates wiring operation.

[0035] In a further embodiment, referring to Figure 2 and Figure 4 The box body 1 has a built-in zero-sequence winding 7, which is wound on the outer side of the column at the outermost edge of the iron core 2. Zero-sequence grounding posts 71 are provided at both ends of the zero-sequence winding 7. The zero-sequence winding 7 can be used in a three-phase circuit. Under normal circumstances, the vector sum of the three-phase current is zero; when a single-phase grounding fault occurs, the vector sum of the three-phase current is no longer zero, and a zero-sequence current is generated at the position of the zero-sequence winding 7. By inducing the magnetic flux change of the zero-sequence current, an induced electrical signal is generated in the zero-sequence winding 7, so as to perform single-phase grounding fault detection and improve the applicability of the inductive equipment to the three-phase circuit system.

[0036] In a further embodiment, referring to Figure 1 and Figure 7 The connector 6 also includes a shell 61, which has a top cover that can be opened to reveal the internal zero-sequence connection post 71, voltage terminal 1 62 and voltage terminal 2 63, as well as current terminal 1 64 and current terminal 2 65. The shell 61 is fixed to the top outer wall of the box 1, and the zero-sequence connection post 71 is arranged on the inner side of the shell 61, which is convenient for users to connect to the measuring equipment through a data cable to detect the line and single-phase short circuit.

[0037] In a further embodiment, referring to Figure 10The connector 6 also includes a communication controller 66. The communication controller 66 has built-in measuring instruments, an execution circuit board and a remote communication device. The measuring instruments are voltmeters and ammeters of different ranges. The execution circuit board can turn different relays on or off according to the received control signal. The remote communication device is used to send and receive control signals and detect data. Among them, the communication controller 66 is connected in series between the two zero-sequence connecting posts 71, between the voltage terminal 1 62 and the voltage terminal 2 63, and between the current terminal 1 64 and the current terminal 2 65 through a wiring harness. It can detect the detection voltage between the two zero-sequence connecting posts 71 and can measure the voltage The induced voltage and induced current generated between terminal 1 62 and voltage terminal 2 63, and between current terminal 1 64 and current terminal 2 65, can be sent to the execution circuit board through the remote communication equipment to control the on and off of the voltage terminal relay group and the current terminal relay group, and remotely change the number of turns of the secondary voltage winding 3 and the secondary current winding 4, so as to adapt to different measurement ranges and circuit systems more quickly. When the circuit system is abnormal, such as when the circuit voltage and current increase abnormally, the remote control will reduce the induced voltage and induced current to a minimum, reduce the load on the secondary winding, and minimize the damage to the transformer caused by abnormal fluctuations.

[0038] In a further embodiment, referring to Figure 4 The primary winding 5 includes an insulating sleeve 51, which completely wraps the coil of the primary winding 5. The insulating sleeve 51 has an insulating ability to avoid excessive voltage in the primary winding 5 and breakdown failure between the iron core 2. Figure 5 and Figure 6 The secondary voltage winding 3 includes a voltage isolation sleeve 36, which completely wraps the voltage winding 1 31, the voltage winding 2 32 and the voltage winding 3 33. The secondary current winding 4 includes a current isolation sleeve 46, which completely wraps the current winding 1 41, the current winding 2 42 and the current winding 3 43. The voltage isolation sleeve 36 and the current isolation sleeve 46 can further improve the insulation capacity between the primary winding 5 and the anti-breakdown capability. The zero-sequence winding 7, the primary winding 5, the secondary voltage winding 3 and the secondary current winding 4 are covered with a cover 8 on the outside. The cover 8 increases the contact area with the protective oil inside the box 1 to provide protection and cooling, and assists in reducing the abnormal breakdown and short circuit caused by high temperature of the insulating sleeve 51, the voltage isolation sleeve 36 and the current isolation sleeve 46, thereby ensuring that the sensor works stably in a high voltage environment.

[0039] In a further embodiment, referring to Figure 4The iron core 2 includes a stacked main body 21, which is composed of multiple stacked metal sheets. The metal sheet iron core is made of thin and insulating silicon steel sheets, and an insulating layer is coated between each sheet to reduce eddy current heating. The structural design of the metal sheet iron core makes its heat dissipation area larger, which can effectively reduce the operating temperature. Among them, the top and bottom ends of the main body 21 are clamped and squeezed by two pressure plates 22, and a clamping piece 23 is connected between the two pressure plates 22. The pressure plate 22 is pressed against the main body 21 through the detachable clamping piece 23. The overall structure is stable. When the insulation layer is damaged due to heat, it can also be quickly disassembled for replacement and maintenance, and the later maintenance cost is low.

[0040] The above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention.

Claims

1. A multi-stage combined voltage transformer, characterized in that: include: A box body (1), wherein the interior of the box body (1) forms a sealed space, and a vertical side wall of the box body (1) is provided with an oil nozzle (12); An iron core (2), wherein the iron core (2) adopts a five-column shape and is placed in a sealed space; A primary winding (5), wherein the primary winding (5) is provided with three windings and is wound around the outside of three upright posts in the center of the iron core (2); A secondary voltage winding (3), wherein the secondary voltage winding (3) is provided with three and is sleeved on the outside of the column above the primary winding (5), including a voltage winding one (31), a voltage winding two (32) and a voltage winding three (33), wherein two ends of the voltage winding one (31), the voltage winding two (32) and the voltage winding three (33) are provided with a voltage connecting post one (37), a voltage connecting post two (38) and a voltage connecting post three (39) respectively; A secondary current winding (4), wherein the secondary current winding (4) is provided with three and is sleeved on the outside of the column below the primary winding (5), including a current winding one (41), a current winding two (42) and a current winding three (43), and the two ends of the current winding one (41), the current winding two (42) and the current winding three (43) are respectively provided with a current connecting column one (47), a current connecting column two (48) and a current connecting column three (49); A connector (6), the connector (6) includes a voltage terminal 1 (62) and a voltage terminal 2 (63), and a current terminal 1 (64) and a current terminal 2 (65), wherein the voltage terminal 1 (62) and the voltage terminal 2 (63) are electrically connected to the voltage winding 1 (31), the voltage winding 2 (32) and the voltage winding 3 (33) via a voltage terminal relay group, and the current terminal 1 (64) and the current terminal 2 (65) are electrically connected to the current winding 1 (41), the current winding 2 (42) and the current winding 3 (43) via a current terminal relay group.

2. The multi-stage combined voltage transformer according to claim 1, characterized in that: The voltage terminal relay group includes a voltage terminal relay 1 (631), a voltage terminal relay 2 (632), a voltage terminal relay 3 (633), a voltage terminal relay 4 (634) and a voltage terminal relay 5 (635). The voltage terminal relay 1 (37) at one end of the voltage winding 1 (31) is electrically connected to the voltage terminal 1 (62). The voltage terminal relay 1 (37) at the other end of the voltage winding 1 (31) is connected in parallel with the voltage terminal relay 1 (631) and the voltage terminal relay 2 (632). The voltage terminal relay 2 (38) at one end of the voltage winding 2 (32) is connected in parallel with the voltage terminal relay 1. (631) is electrically connected, the voltage terminal post 2 (38) at the other end of the voltage winding 2 (32) is connected in parallel with the voltage terminal relay 3 (633) and the voltage terminal relay 4 (634), the voltage terminal post 3 (39) at one end of the voltage winding 3 (33) is electrically connected to the voltage terminal relay 3 (633), the voltage terminal post 3 (39) at the other end of the voltage winding 3 (33) is connected in series with the voltage terminal relay 5 (635), and the voltage terminal relay 2 (632), the voltage terminal relay 4 (634) and the voltage terminal relay 5 (635) are connected in parallel at the end of the voltage terminal 2 (63).

3. The multi-stage combined voltage transformer according to claim 1, characterized in that: The current end relay group includes a current end relay 1 (651), a current end relay 2 (652), a current end relay 3 (653), a current end relay 4 (654) and a current end relay 5 (655). The current connecting post 1 (47) at one end of the current winding 1 (41) is electrically connected to the current terminal 1 (64). The current connecting post 1 (47) at the other end of the current winding 1 (41) is connected in parallel with the current end relay 1 (651) and the current end relay 2 (652). The current connecting post 2 (48) at one end of the current winding 2 (42) is connected in parallel with the current end relay 1. (651) is electrically connected, the current connecting post 2 (48) at the other end of the current winding 2 (42) is connected in parallel with the current terminal relay 3 (653) and the current terminal relay 4 (654), the current connecting post 3 (49) at one end of the current winding 3 (43) is electrically connected to the current terminal relay 3 (653), the current connecting post 3 (49) at the other end of the current winding 3 (43) is connected in series with the current terminal relay 5 (655), and the current terminal relay 2 (652), the current terminal relay 4 (654) and the current terminal relay 5 (655) are connected in parallel at the end of the current terminal 2 (65).

4. The multi-stage combined voltage transformer according to claim 1, characterized in that: Voltage sub-wires (34) are respectively provided at both ends of the voltage winding 1 (31), the voltage winding 2 (32) and the voltage winding 3 (33). The three voltage sub-wires (34) located on the same side are combined to form a voltage winding harness (35). The secondary voltage winding (3) is provided with two voltage winding harnesses (35) in total.

5. The multi-stage combined voltage transformer according to claim 1, characterized in that: The two ends of the current winding 1 (41), the current winding 2 (42) and the current winding 3 (43) are respectively provided with current sub-wires (44), and the three current sub-wires (44) located on the same side are combined to form a current winding wire bundle (45). The secondary current winding (4) is provided with two current winding wire bundles (45) in total.

6. The multi-stage combined voltage transformer according to claim 1, characterized in that: The box (1) has a built-in zero-sequence winding (7), which is wound on the outside of the column at the outermost edge of the iron core (2), and zero-sequence connection posts (71) are provided at both ends of the zero-sequence winding (7).

7. The multi-stage combined voltage transformer according to claim 6, characterized in that: The connector (6) further comprises a shell (61), wherein the shell (61) is fixed to the top outer wall of the box body (1), and the zero-sequence connecting post (71) is arranged on the inner side of the shell (61).

8. The multi-stage combined voltage transformer according to claim 1, characterized in that: The connector (6) further includes a communication controller (66), which is connected in series between two zero-sequence connecting posts (71), between voltage terminal 1 (62) and voltage terminal 2 (63), and between current terminal 1 (64) and current terminal 2 (65) through a wiring harness.

9. The multi-stage combined voltage transformer according to claim 6, characterized in that: The primary winding (5) includes an insulating sleeve (51), and the insulating sleeve (51) completely wraps the coil of the primary winding (5); the secondary voltage winding (3) includes a voltage isolating sleeve (36), and the voltage isolating sleeve (36) completely wraps the voltage winding one (31), the voltage winding two (32), and the voltage winding three (33); the secondary current winding (4) includes a current isolating sleeve (46), and the current isolating sleeve (46) completely wraps the current winding one (41), the current winding two (42), and the current winding three (43); the zero-sequence winding (7), the primary winding (5), the secondary voltage winding (3), and the secondary current winding (4) are covered with a cover (8) on the outside.

10. The multi-stage combined voltage transformer according to claim 1, characterized in that: The iron core (2) comprises a main body (21) arranged in a stacked manner, the top and bottom ends of the main body (21) are clamped and squeezed by two pressing plates (22), and a pressing member (23) is connected between the two pressing plates (22).

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