CN207800347U - Distribution automation three-phase zero sequence integral type anti-resonance potential transformer - Google Patents

Abstract

The utility model relates to high-voltage measurement or relay protection equipment of an electric power system, in particular to a three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation. It includes a base, a main insulator arranged on the base, and a three-phase voltage body and a zero-sequence voltage body packaged in the main insulator. Two primary insulating columns and three primary insulators are arranged on the upper part of the main insulator. Cable sockets, the three primary cable sockets are respectively provided with a primary conductor, the main insulator is provided with a zero-sequence terminal, the lower part of the main insulator is provided with a secondary junction box, and the secondary junction box is provided with There are secondary terminals. The utility model is formed by vacuum casting of epoxy resin. The product has the characteristics of small size, flexible installation, stable insulation, full sealing and maintenance-free, and realizes full insulation, full sealing, small volume, compact structure and flexible installation of the ring network cabinet. , maintenance-free, safe operation and other main functions.

Description

Three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation

technical field

The utility model relates to high-voltage measurement or relay protection equipment of an electric power system, in particular to a three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation.

Background technique

A voltage transformer is a device for measuring voltage and electric energy in a power system or an electrical control system. The current oil-immersed voltage transformer used as an inductance element is affected by some external excitation factors of the network, and ferromagnetic resonance often occurs, which affects the reliability of the power grid operation; or four dry-type single-phase voltage transformers are used The anti-ferromagnetic resonance voltage transformer is connected externally to achieve the purpose of anti-ferromagnetic resonance, but the installation and wiring are relatively cumbersome; the indoor anti-ferromagnetic resonance voltage transformer uses four voltage transformers assembled into an integrated structure through an external iron core, the so-called The insulation maintenance of semi-closed, ferromagnetic resonance and oil-immersed voltage transformers is recognized as a serious problem by the power sector. Frequent problems have caused great economic losses and increased a lot of manpower and material resources. In addition, the product is required to have its own high-voltage insurance, power winding and other functions to meet the requirements of supporting automation equipment. At present, there is no product with this performance in the industry. Although the existing dry-type products can be additionally equipped with fuse devices, However, because it will cause the overall structure size to be too large and increase the equipment cost, it will also add a lot of difficulties to the later equipment maintenance and other work. In order to achieve three-phase voltage measurement or electrical protection, solve defects such as oil leakage, complicated installation, complicated wiring, tight insulation space, large size, regular maintenance and unreliable insulation, etc., and also improve the design and manufacturing level of switchgear as a whole , to realize the indoor performance, full insulation, small size, flexible installation, flexible wiring, and maintenance-free features of the ring network cabinet. In particular, it is necessary to design and develop a three-phase elbow seat type zero sequence matching with the ring network cabinet. Integrated anti-ferromagnetic resonance voltage transformer.

Utility model content

In view of the above problems, the purpose of this utility model is to provide a three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation to solve the problems of existing voltage transformers such as oil leakage, complicated installation, complicated wiring, and tight insulation space. , large volume, regular maintenance and unreliable insulation.

In order to achieve the above object, the utility model adopts the following technical solutions:

A three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation, including a base, a main insulator arranged on the base, and a three-phase voltage transformer body and a zero-sequence voltage transformer body packaged in the main insulator , the upper part of the main insulator is provided with two primary insulation columns and three primary cable sockets, and a primary conductor is respectively provided in the three primary cable sockets, and a zero-sequence terminal is provided in the main insulator. The lower part of the insulator is provided with a secondary junction box, and the secondary junction box is provided with a secondary connection terminal.

The three-phase voltage body includes A, B, and C-phase voltage bodies arranged longitudinally and parallel to each other, and the zero-sequence voltage body is arranged on the rear side of the three-phase voltage body and arranged laterally.

The body of the A, B, and C-phase voltage transformers and the zero-sequence voltage transformer body have the same structure, including a secondary winding, a primary winding and an iron core, and the secondary winding and the primary winding are concentrically wound on an insulating frame The latter is fitted on the iron core.

A low-voltage shielding network is provided outside the primary winding.

The primary cable socket is a hollow truncated conical structure, and a primary high-voltage fuse for connecting with a high-voltage cable is enclosed inside it.

The periphery of the primary cable socket is provided with a metal clip, and the metal clip is used to fix the cable plug of the high-voltage cable that is sealed and inserted into the primary cable socket.

The three primary cable sockets are equidistantly arranged on the side of the main insulator and arranged along the horizontal direction.

The secondary junction box is sealed by the cover plate of the secondary junction box, and the position of the secondary outlet is provided with an externally forced cable fixing head, and the secondary junction box and the main insulator are of an integrated structure.

The left, right and rear parts of the main insulator are provided with grooves for handling.

The two primary insulating columns are located on the top of the main insulator and are arranged laterally on the rear side of the three primary cable sockets. Each of the primary insulating columns is provided with arc-shaped sheds of alternate sizes. A rubber sleeve is sleeved on the O end of the primary insulating column.

Advantage and beneficial effect of the present utility model are:

1. This utility model is made of epoxy resin vacuum casting, with fuse protection function, small size, flexible installation, indoor dry-type three-phase elbow seat type zero-sequence integrated fully enclosed anti-ferromagnetic resonance three-phase voltage mutual induction It is suitable for indoor use, and it is equipped with outdoor switch box automation complete equipment for vacuum, SF6 and load column switches.

2. This utility model is a three-phase four-wire system transformer with 220 stable power supply: when the online 100V monitoring function is realized, it has a three-phase 220V stable long-term power supply function for switching electromagnetic mechanisms and power supplies, and the maximum instantaneous output of the power supply reaches 3000VA /S.

3. Phase selection for zero-sequence faults of the utility model: when the product is 10-100% grounded in the system, the fault phase sequence can be directly judged by monitoring the voltage signal of the winding on-line, and the fault signal can be directly transmitted out of the automation device, which is convenient for instant fault exclude.

4. The self-current-limiting protection of the utility model and the integrated type of American elbow seat: the A, B, and C terminals of the product are connected and fixed by American elbow, and the high-voltage current-limiting fuse is concentrically installed inside the American elbow, fully insulated and sealed , Easy to install and replace.

5. Anti-resonance of the utility model: the anti-resonance principle design of four voltage transformers is adopted, and the product will operate safely in the event of a 100% grounding fault in the system, and there will be no ferromagnetic resonance fault.

6. The utility model is fully shielded and anti-interference: the internal optimization of the product adopts the shielding technology of prefabricated 16-mesh drawing material to realize the product can be operated with electricity, and effectively prevent external electromagnetic interference, and the product performance is stable and reliable.

Description of drawings

Fig. 1 is the front view of the external structure of the utility model;

Fig. 2 is the top view of the external structure of the utility model;

Fig. 3 is a side view of the internal structure of the utility model;

Fig. 4 is the wiring diagram of the use principle of the utility model.

In the figure: 1 is the body of the three-phase voltage device; 2 is the body of the zero-sequence voltage device; 3 is the primary conductor; 4 is the primary insulating column; 5 is the primary cable socket; 6 is the primary high-voltage fuse; 7 is the secondary junction box ; 8 is the base; 9 is the arc-shaped shed; 10 is the rubber sleeve; 11 is the forced cable gland; 12 is the main insulator; 13 is the groove; 14 is the core; 15 is the primary winding; 16 is the secondary winding ; 17 is a low-voltage shielding net; 18 is a secondary junction box cover; 19 is a metal deck; 20 is a protection device.

Detailed ways

In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1-3, a three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation provided by the utility model includes a base 8, a main insulator 12 arranged on the base 8 and a main insulator 12 packaged Three-phase voltage device body 1 and zero-sequence voltage device body 2 inside, two primary insulating columns 4 and three primary cable sockets 5 are provided on the upper part of the main insulator 12, and a primary conductor is respectively provided in the three primary cable sockets 5 3. The main insulator 12 is provided with a zero-sequence terminal, the lower part of the main insulator 12 is provided with a secondary junction box 7, and the secondary junction box 7 is provided with a secondary terminal.

The three-phase voltage body 1 includes A, B, and C-phase voltage bodies arranged longitudinally and parallel to each other. The zero-sequence voltage body 2 is arranged on the rear side of the three-phase voltage body 1 and arranged laterally. After the four voltage transformer bodies are connected by the primary wire according to the principle of anti-ferromagnetic resonance, the three A, B, and C three-phase voltage transformer bodies are placed in parallel and longitudinally, and the zero-sequence voltage transformer body 2 is horizontally behind the three-phase voltage transformer body 1. Placement to ensure the insulation distance between the product phases, effectively use the space, and ensure the insulation distance between the product phases.

A, B, C phase voltage body and zero-sequence voltage body 2 have the same structure, including secondary winding 16, primary winding 15 and iron core 14, secondary winding 16 and primary winding 15 are concentrically wound on an insulating frame and then packaged On core 14.

A low-voltage shielding network 17 is provided outside the primary winding 15 of the A and C-phase voltage transformer body 1 and the zero-sequence voltage transformer body 2 .

The primary cable socket 5 is a hollow truncated cone structure, and a primary high-voltage fuse 6 for connecting with a high-voltage cable is enclosed inside it. The periphery of the primary cable socket 5 is provided with a metal clip 19, and the metal clip 19 is used to fix the cable plug of the high-voltage cable that is sealed and inserted into the primary cable socket 5.

The primary cable sockets 5 of phase A, phase B and phase C are respectively sealed with primary high-voltage fuses 6 to effectively protect the product from damage when the system fails. The primary three-phase terminal is in the form of three identical primary cable sockets 5, which can be conveniently sealed and plugged with the cable plug of the high-voltage cable to realize electrical connection.

The three primary cable sockets 5 are equidistantly arranged on the upper side of the main insulator 12 and arranged along the horizontal direction, so as to be conveniently connected with the cable plugs of high-voltage cables.

The secondary junction box 7 is sealed by the secondary junction box cover plate 18, and the secondary outlet position is provided with an externally forced cable fixing head 11, which ensures that the secondary cable is reliably sealed and clamped after the secondary cable connection is completed; the secondary wiring The box 7 and the main insulator 12 are integrally structured.

The left and right sides and the rear of the main insulator 12 are provided with grooves 13 for easy handling, which is convenient for flexible handling and installation when the switchgear is assembled, and is convenient for product replacement and disassembly during future field use.

The two primary insulating columns 4 are located on the top of the main insulator 12 and arranged laterally behind the three primary cable sockets 5 . Each primary insulating column 4 is provided with arc-shaped sheds 9 of alternate sizes. An N terminal (ground) and an O terminal (neutral point) are respectively provided in the two primary insulating posts 4 , and a rubber sleeve 10 is sheathed on the primary insulating post 4 provided with the O terminal.

The making process of the present utility model is:

The secondary winding 16 and the primary winding 15 are concentrically wound on an insulating frame and then set on the iron core 14. After being insulated and buffered, a three-phase voltage body of A, B, and C is formed. Similarly, a zero-sequence voltage body is formed. 2. Four voltage device bodies, three primary conductors 3 and three low-voltage shielding nets 17 are respectively fixed in the casting mold, and then the three-phase and zero-sequence terminals are connected for relevant electrical connections, and the surrounding insulation distance is adjusted. Then close the mold, adopt epoxy resin to vacuum cast and solidify to form an integrated fully enclosed structure, put a rubber sleeve 10 on the O end of the primary insulating column 4 to seal, and finally install it on the base 8 as a whole. Then it becomes: the primary three-phase terminal is in the form of three identical primary cable sockets 5, which can be conveniently sealed and plugged with the cable plug of the high-voltage cable to realize electrical connection; the inner hollow cylinder of the primary cable socket 5 is used as a primary high-voltage The space for the fuse 6; the base of the primary cable socket 5 has a metal holder 19 with round holes around the root of the frustum of the cone, which is used for fixing the high-voltage cable plug and the primary cable socket; the primary cable socket 5 is located in the integral structure The upper side is uniformly arranged horizontally at equal distances, which is convenient for the layout design of high-voltage cable plugs and high-voltage cables; inside the product, there are three low-voltage shielding nets on the outside of the primary winding 15 of the A and C-phase voltage body and the zero-sequence voltage body 2 17. It can effectively shield the high-voltage electric field inside the product to realize the function of live operation; the main insulator 12 is provided with a groove 13 for easy handling, which is convenient for flexible handling and installation during switchgear assembly, and includes product maintenance during on-site use in the future Easy to replace and disassemble; the secondary junction box 7 is located at the lower side of the integral structure, and the secondary junction box cover plate 18 is made of metal material. After matching with the sealing rubber pad, the secondary junction box 7 is reliably sealed and waterproof Function: the position of the secondary outlet has a waterproof externally forced cable fixing head 11, which ensures that the secondary cable is reliably sealed and clamped after the secondary cable is connected.

When in use, the installation procedure of the voltage transformer is mainly divided into three main steps. The first step: use the installation base 8 to install the transformer as a whole in the design position of the ring network cabinet; the second step is to connect the fixed end of the primary high-voltage fuse once Then insert the cable plug into the primary socket of the transformer. After reliable contact, use the cable fixing piece and the metal holder 19 to position and fix the cable plug; the third step: carry out the secondary wiring of the voltage transformer, and the secondary cable passes through the forced The cable fixing head 11 is sealed and tightened, and then the secondary terminal is sealed with the secondary junction box cover plate 18 and the sealing rubber pad; the installation of the three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation is convenient and flexible.

The utility model three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation is a new product designed completely in accordance with national standards. It adopts rolled iron core and uses the principle of electromagnetic conversion to make the secondary voltage accurately reflect the primary voltage. The change of the situation, and the reasonable electrical connection is made inside the product according to the principle of anti-ferromagnetic resonance, so that the product can be directly installed in the indoor three-phase line.

As shown in Figure 4, three voltage transformer bodies form a three-phase group, and the primary star-shaped neutral point of the three-phase group is grounded through the primary winding of the fourth zero-sequence voltage transformer body, that is, the N point is grounded; The star-shaped neutral point is grounded through the secondary winding of the fourth zero-sequence voltage device, that is, point n is grounded; the secondary body of the zero-sequence voltage device has a ground monitoring winding (da, dn) and a basic winding (on); The star-shaped neutral point of the three-phase group is equivalent to high-impedance grounding, and the windings of each phase are connected across the phase-to-phase voltage of the power supply, and are no longer associated with the grounding capacitor, so there will be no neutral point displacement, and there will be no Ferromagnetic resonance, in which the basic secondary winding is used for normal three-phase power measurement, and the ground monitoring winding (da, dn) is used for ground protection. When a ground fault occurs in any phase of the system or the system resonates, the neutral point shifts, causing the neutral point voltage to rise rapidly, driving the protection winding voltage transformer to start working, and generating a voltage between the neutral point and the ground. When the voltage value is equal to or exceeds the rated voltage, the secondary terminal of the protection winding will generate a voltage of 100V and above, which will drive the voltage relay to act and play a protective role. If the neutral point voltage is lower than the rated voltage, even when a single-phase ground fault occurs in the system, this transformer can also run for a long time, and the grounding corresponding to the secondary grounding monitoring winding is (da, dn) connected to the protection device 20 relays or Used for microcomputer monitoring, the secondary side voltmeter can display the offset of the neutral point. When a single-phase 100% ground fault occurs in the system, this voltage transformer can still run for a long time even if the system does not resonate or the protection relay does not operate. The voltage transformer used for protection can also play a measuring role. In addition, the anti-ferromagnetic resonance performance is fully considered in the design of this product, and the rated magnetic flux density is designed to be relatively low, which is not easy to cause magnetic flux saturation and resonance. When the system is operating normally, the output voltage of the protection winding is ≤10V. It will not cause malfunction of the relay; in addition, this type of transformer can also provide 220V regulated power supply for the switch electromagnetic mechanism of the electrical equipment of the ring main unit and the DTU power supply.

The utility model is formed by vacuum casting of epoxy resin. The product has the characteristics of small size, flexible installation, stable insulation, full sealing, and maintenance-free, and realizes full insulation, full sealing, small volume, compact structure, and flexible installation of the ring network cabinet. , maintenance-free, safe operation and other main functions, making the power system ring network power supply technical quality level a bigger step forward.

The above descriptions are only the embodiments of the present utility model, and are not intended to limit the protection scope of the present utility model. All modifications, equivalent replacements, improvements, extensions, etc. made within the spirit and principles of the present utility model are included in the protection scope of the present utility model.

Claims (10)

1. A three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation, characterized in that it includes a base (8), a main insulator (12) that is arranged on the base (8) and is packaged in the The three-phase voltage body (1) and the zero-sequence voltage body (2) in the main insulator (12), the upper part of the main insulator (12) is provided with two primary insulation columns (4) and three primary cable sockets (5), the three primary cable sockets (5) are respectively provided with a primary conductor (3), the main insulator (12) is provided with a zero-sequence terminal, and the lower part of the main insulator (12) is provided with A secondary junction box (7), the secondary junction box (7) is provided with a secondary junction terminal. 2. The three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation according to claim 1, characterized in that, the three-phase voltage transformer body (1) includes A, B arranged longitudinally and parallel to each other . The C-phase voltage body, the zero-sequence voltage body (2) is arranged on the rear side of the three-phase voltage body (1), and is arranged along the lateral direction. 3. The three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation according to claim 2, wherein the A, B, and C-phase voltage transformer bodies and the zero-sequence voltage transformer body (2 ) have the same structure, including secondary windings (16), primary windings (15) and iron cores (14), the secondary windings (16) and the primary windings (15) are concentrically wound on an insulating frame and then sleeved on on the iron core (14). 4. The three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation according to claim 3, characterized in that, the A, C-phase voltage body and the zero-sequence voltage body (2) A low-voltage shielding network (17) is provided outside the primary winding (15). 5. The three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation according to claim 1, characterized in that, the primary cable socket (5) is a hollow frustum-conical structure, and its interior is sealed with a A primary high voltage fuse (6) connected to the high voltage cable. 6. The three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation according to claim 5, characterized in that, the periphery of the primary cable socket (5) is provided with a metal deck (19), the The metal holder (19) is used to fix the cable plug of the high-voltage cable that is sealed and plugged into the primary cable socket (5). 7. The three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation according to claim 1, wherein the three primary cable sockets (5) are equidistantly arranged on the main insulator (12) sideways and arranged horizontally. 8. The three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation according to claim 1, characterized in that, the secondary junction box (7) is sealed by the secondary junction box cover plate (18), In addition, an externally forced cable fixing head (11) is provided at the position of the secondary outlet, and the secondary junction box (7) and the main insulator (12) are integrally structured. 9. The three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation according to claim 1, characterized in that, the left and right sides and the rear of the main insulator (12) are provided with grooves for handling (13). 10. The three-phase zero-sequence integrated anti-resonance voltage transformer for distribution network automation according to claim 1, wherein the two primary insulating columns (4) are located on the top of the main insulator (12), And horizontally arranged on the rear side of the three primary cable sockets (5), each of the primary insulating columns (4) is provided with arc-shaped sheds (9) of alternate sizes, and the primary insulating columns (4) The O end of the sleeve is provided with a rubber sleeve (10).