CN205335051U - Three -phase combination transformer - Google Patents

Abstract

The utility model provides a three -phase combination transformer, including the three single -phase unit that connects gradually, this three single -phase unit is first single -phase unit, the single -phase unit of second and the single -phase unit of third respectively, and every single -phase unit includes from inside to outside in proper order: iron core, low voltage coil, middling pressure coil, high -pressure coil and voltage regulation coil, wherein, the single -phase unit of second still includes: the anti ware of three single phase power, the anti ware of three single phase power respectively with three single -phase unit in low voltage coil be connected. The technical scheme of the utility model, the problem that current high impedance transformer insulation system is complicated, with high costs, realize the difficulty has been solved.

Description

Three-phase combined transformer

technical field

The utility model relates to the technical field of electric power, in particular to a three-phase combined transformer.

Background technique

The three-phase combined transformer refers to a transformer formed by connecting three single-phase transformers of independent units to the lead wires of the transmission voltage through interphase pipelines, and reassembled and installed on one basis on site. Each independent unit of the three-phase transformer, that is, each single-phase transformer can be transported separately, which can meet the use requirements of power stations with harsh transportation conditions and inconvenient transportation, and save transportation costs. The high-impedance transformer can effectively reduce the short-circuit current of the power system and improve the reliability of the power grid. At the same time, it can also reduce the breaking capacity of electrical equipment such as line switches. The construction cost and the floor area are reduced. Therefore, the three-phase combined transformer with high impedance has been widely used in the power system.

At present, the impedance voltage of three-phase combined transformer mainly has the following forms:

It can be seen that compared with standard impedance transformers, medium impedance and high impedance transformers have much higher impedance voltage changes of "medium voltage-low voltage" and "high voltage-low voltage". Therefore, medium impedance transformers and high impedance transformers Transformers are collectively referred to as high impedance transformers.

At present, the impedance of the transformer is mainly increased by building the high-voltage coil or splitting the medium-voltage coil. Among them, the built-in method of the high-voltage coil is to arrange a high-voltage coil, a medium-voltage coil, a voltage-regulating coil and a low-voltage coil on the outside of the iron core from the inside to the outside. This method can effectively improve the short-circuit impedance and short-circuit resistance capability of the transformer, and reduce the load loss during operation. However, the voltage difference between the high-voltage coil and the low-voltage coil is too large, which makes the insulation structure of the transformer complicated and the cost of the transformer high. , High risk. The method of splitting the medium-voltage coil is to divide the medium-voltage coil into an inner medium-voltage coil and an outer medium-voltage coil. Specifically, the high-voltage coil is arranged between the inner medium-voltage coil and the outer medium-voltage coil to increase the impedance voltage of the transformer. However, the insulation structure of the transformer made by this method is complicated and the cost is relatively high.

Therefore, although the above-mentioned methods of improving transformer impedance are used in three-phase combined transformers, they all have the defects of complicated insulation structure and high cost. In addition, because the three-phase combined transformer is formed by connecting three single-phase transformers, The circuit and the magnetic circuit work independently, and the lead wire structure when the three single-phase transformers are connected into Y connection and △ connection inside the oil tank is particularly complicated, and it is difficult to realize.

Utility model content

The utility model provides a three-phase combined transformer to solve the problems of complex insulation structure, high cost and difficult realization of the existing high-impedance transformer.

A three-phase combined transformer provided by the utility model includes three single-phase units connected in sequence, and the three single-phase units are respectively the first single-phase unit, the second single-phase unit and the third single-phase unit, Each single-phase unit includes, from inside to outside, an iron core, a low-voltage coil, a medium-voltage coil, a high-voltage coil, and a voltage-regulating coil;

The second single-phase unit further includes: three single-phase reactors, and the three single-phase reactors are respectively connected to the low-voltage coils in the three single-phase units.

In an embodiment of the present utility model, the second single-phase unit further includes: three low-voltage lead-out bushings;

The three low-voltage lead-out bushings are respectively connected to the low-voltage coils in the three single-phase units, and the three low-voltage lead-out bushings are used to lead out the three low-voltage output terminals of the three single-phase units.

In another embodiment of the present utility model, the iron core in each single-phase unit is a single-phase three-column structure.

In the above embodiments of the present utility model, each iron core in the single-phase unit includes: a core column, an iron yoke, and side columns arranged on both sides of the core column, and the core column, the iron yoke the yoke and the side post are secured together by clamps;

The outer side of the stem is sequentially provided with the low voltage coil, the medium voltage coil, the high voltage coil and the voltage regulation coil from inside to outside.

In yet another embodiment of the present utility model, the second single-phase unit further includes: a voltage regulating switch;

The voltage regulating switch is a three-phase on-load voltage regulating switch, and the three phases of the voltage regulating switch are respectively connected to the high-voltage coil and the voltage regulating coil of the first single-phase unit, and connected to the voltage regulating coil of the second single-phase unit. The high-voltage coil is connected to the voltage-regulating coil, and is connected to the high-voltage coil and the voltage-regulating coil of the third single-phase unit, and the voltage-regulating switch is used to adjust the number of turns of the voltage-regulating coil in the three single-phase units , to adjust the high-voltage output of the high-voltage coils in the three single-phase units.

In still another embodiment of the present utility model, the first single-phase unit and the second single-phase unit, the second single-phase unit and the third single-phase unit are respectively connected to each other through two bellows , one of the bellows is a channel for medium-voltage star connection leads and low-voltage angle connection leads, and the other bellows is a channel for high-voltage star connection leads.

In the above embodiments of the present utility model, the bellows are metal bellows.

The three-phase combined transformer provided by the utility model connects three single-phase units sequentially, and each single-phase unit sequentially includes an iron core, a low-voltage coil, a medium-voltage coil, a high-voltage coil and a voltage regulating coil from the inside to the outside, and Three single-phase reactors are installed in the second single-phase unit, and the single-phase reactors are connected in series in the low-voltage coil through the lead wires to finally complete the △ connection between the three phases. The lead wires are easy to connect and easy to implement, and can meet the high impedance of the transformer. It solves the problems of complex insulation structure, high cost and difficult realization of existing high-impedance transformers.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the appended drawings in the following description The drawings are some embodiments of the utility model, and those skilled in the art can also obtain other drawings according to these drawings on the premise of not paying creative labor.

Fig. 1 is the structural representation of embodiment one of three-phase combined transformer provided by the utility model;

Fig. 2 is a schematic arrangement diagram of the first single-phase unit coil in the three-phase combined transformer provided by the utility model;

Fig. 3 is the schematic arrangement diagram of the second single-phase unit coil in the three-phase combined transformer provided by the utility model;

Fig. 4 is a schematic diagram of the arrangement of the third single-phase unit coil in the three-phase combined transformer provided by the utility model;

Fig. 5 is a structural schematic diagram of the second embodiment of the three-phase combined transformer provided by the utility model;

Fig. 6 is a schematic diagram of the connection between the single-phase reactor and the low-voltage lead-out bushing in the three-phase combined transformer provided by the present invention.

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the utility model more clear, the technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the utility model. Obviously, the described The embodiments are some embodiments of the present utility model, but not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

The utility model provides a three-phase combined transformer, which is suitable for the technical field of power transformer manufacturing and is used to solve the problems of complex insulation structure, high cost and difficult realization of the existing high-impedance transformer.

Fig. 1 is a schematic structural diagram of Embodiment 1 of a three-phase combined transformer provided by the present invention. Fig. 2 is a schematic arrangement diagram of the first single-phase unit coils in the three-phase combined transformer provided by the present invention. Fig. 3 is a schematic arrangement diagram of the second single-phase unit coils in the three-phase combined transformer provided by the present invention. Fig. 4 is a schematic diagram of the arrangement of the third single-phase unit coils in the three-phase combined transformer provided by the present invention.

As shown in Figure 1, the three-phase combined transformer provided by the first embodiment of the utility model includes three single-phase units connected in sequence, and the three single-phase units are respectively the first single-phase unit 10 and the second single-phase unit 20 And the third single-phase unit 30 , each single-phase unit includes: an iron core, a low-voltage coil, a medium-voltage coil, a high-voltage coil and a voltage-regulating coil in sequence from the inside to the outside.

Wherein, the second single-phase unit 20 further includes: three single-phase reactors, and the three single-phase reactors are respectively connected to the low-voltage coils in the above-mentioned three single-phase units.

Specifically, as shown in Figures 1 and 2, the first single-phase unit 10 includes: a first iron core 101, a first low voltage coil 102, a first medium voltage coil 103, a first high voltage coil 104 and a first voltage regulating coil 105, and the first single-phase unit 10 is sequentially arranged as a first iron core 101, a first low voltage coil 102, a first medium voltage coil 103, a first high voltage coil 104 and a first voltage regulation coil 105 from inside to outside.

As shown in Figures 1 and 4, the third single-phase unit 30 includes: a third iron core 301, a third low voltage coil 302, a third medium voltage coil 303, a third high voltage coil 304 and a third voltage regulating coil 305, and The third single-phase unit 30 is sequentially arranged as a third iron core 301 , a third low voltage coil 302 , a third medium voltage coil 303 , a third high voltage coil 304 and a third voltage regulating coil 305 from inside to outside.

As shown in Figures 1 and 3, the second single-phase unit 20 includes: a second iron core 201, a second low-voltage coil 202, a second medium-voltage coil 203, a second high-voltage coil 204, and a second voltage-regulating coil 205, and The second single-phase unit 20 is sequentially arranged as a second iron core 201 , a second low voltage coil 202 , a second medium voltage coil 203 , a second high voltage coil 204 and a second voltage regulating coil 205 from inside to outside.

The low-voltage coils are built in the above three single-phase units, that is, the single-phase units are limited to include iron cores, low-voltage coils, medium-voltage coils, high-voltage coils and voltage regulating coils from the inside to the outside, and the iron core and ground wire In this case, the voltage difference between the voltage on the low-voltage coil and the high-voltage coil is reduced, the insulation structure of the transformer is simplified, the manufacturing cost of the transformer is reduced, and the risk is reduced.

In addition, as shown in FIG. 1, three single-phase reactors are set in the second single-phase unit 20, and the three single-phase reactors are respectively the first single-phase reactor 106, the second single-phase reactor 206 and the second single-phase reactor 206. Three single-phase reactors 306 . Specifically, the first single-phase reactor 106 is connected to the first low-voltage coil 102 , the second single-phase reactor 206 is connected to the second low-voltage coil 202 , and the third single-phase reactor 306 is connected to the third low-voltage coil 302 .

It can be seen from the table in the background technology that the corresponding standard impedance, medium impedance and high impedance related to the change of low voltage have changed significantly, while the standard impedance, medium impedance and high impedance corresponding to the change of "high voltage-medium voltage" are the same, therefore, The single-phase reactor in the utility model only needs to be connected in series with the low-voltage coil in the single-phase unit.

It is worth noting that the above-mentioned single-phase reactor can be an air-core reactor or an iron-core reactor, and its reactance value can be set to an impedance voltage of 16% to 27% according to the difference between the high impedance and the standard impedance or needs to reach value.

The three-phase combined transformer provided by the utility model connects three single-phase units sequentially, and each single-phase unit sequentially includes an iron core, a low-voltage coil, a medium-voltage coil, a high-voltage coil and a voltage regulating coil from the inside to the outside, and Three single-phase reactors are installed in the second single-phase unit, and the single-phase reactors are connected in series in the low-voltage coil through the lead wires to finally complete the △ connection between the three phases. The lead wire connection is simple and easy to implement, which can meet the high impedance of the transformer The requirements of the existing high-impedance transformers are solved, the insulation structure is complicated, the cost is high, and the problems of difficult realization are solved.

Fig. 5 is a schematic structural diagram of Embodiment 2 of the three-phase combined transformer provided by the present invention. Fig. 6 is a schematic diagram of the connection between the single-phase reactor and the low-voltage lead-out bushing in the three-phase combined transformer provided by the present invention. Embodiment 2 of the present utility model further explains the three-phase combined transformer on the basis of Embodiment 1 above. As shown in FIG. 5 , in the three-phase combined transformer provided in Embodiment 2 of the present utility model, the second single-phase unit 20 further includes: three low-voltage lead-out bushings.

The three low-voltage lead-out bushings are respectively connected to the low-voltage coils in the above-mentioned three single-phase units, and are used to lead out the three low-voltage output terminals of the three single-phase units.

As shown in Figure 5 and Figure 6, the three low-voltage lead-out bushings in the embodiment of the present invention are the first low-pressure lead-out bushing 107, the second low-pressure lead-out bushing 207 and the third low-pressure lead-out bushing 307, the first The low-voltage lead-out bushing 107 is connected to the first low-voltage coil 102 in the first single-phase unit 10, the second low-voltage lead-out bushing 207 is connected to the second low-voltage coil 202 in the second single-phase unit 20, and the third low-voltage lead-out bushing 307 is connected to the third low-voltage coil 302 in the third single-phase unit 30 . The output of each low-voltage lead-out bushing is the voltage converted by the transformer, which is the voltage after the low-voltage coil and the single-phase reactor are connected in series.

In the three-phase combined transformer provided by the embodiment of the utility model, by setting three low-voltage lead-out bushings in the second single-phase unit, the low-voltage coil in each single-phase unit is connected to the single-phase reactance in the second single-phase unit. The transformers are connected in series, and then three adjacent low-voltage lead-out bushings are used to lead out the low-voltage coils to form a voltage output terminal after delta connection, which realizes the high impedance requirement of the three-phase combined transformer.

Further, in the three-phase combined transformer provided in the above embodiment, the iron core in each single-phase unit is a single-phase three-column structure.

The iron core in each single-phase unit includes: core column, iron yoke and side columns arranged on both sides of the core column, the core column, iron yoke and side columns are fixed together by clamps; the outer side of the core column is made of A low-voltage coil, a medium-voltage coil, a high-voltage coil and a voltage-regulating coil are sequentially arranged from the inside to the outside.

Specifically, as shown in FIG. 2, the first iron core 101 in the first single-phase unit 10, the second iron core 201 in the second single-phase unit 20, and the third iron core 301 in the third single-phase unit 30 Both are single-phase three-column structures.

The first iron core 101 in the first single-phase unit 10 includes: a first core column 1011, a first iron yoke (not shown), and first side columns 1012 arranged on both sides of the first core column 1011, the first core The column 1011, the first iron yoke and the first side column 1012 are fixed together by the first clip 1013, and the outer side of the first core column 1011 is provided with the first low-voltage coil 102, the first medium-voltage coil 103, the second A high voltage coil 104 and a first voltage regulating coil 105 .

The second iron core 201 in the second single-phase unit 20 includes: a second core column 2011, a second iron yoke (not shown), and second side columns 2012 arranged on both sides of the second core column 2011, the second core The column 2011, the second iron yoke and the second side column 2012 are fixed together by the second clip 2013, and the outside of the second core column 2011 is provided with the second low-voltage coil 202, the second medium-voltage coil 203, the second Two high-voltage coils 204 and a second voltage-regulating coil 205 .

The third iron core 301 in the third single-phase unit 30 includes: a third core column 3011, a third iron yoke (not shown), and third side columns 3012 arranged on both sides of the third core column 3011, the third core The column 3011, the third iron yoke and the third side column 3012 are fixed together by the third clip 3013, and the outside of the third core column 3011 is provided with the third low-voltage coil 302, the third medium-voltage coil 303, the third Three high-voltage coils 304 and a third voltage-regulating coil 305 .

Further, in the three-phase combined transformer provided in the second embodiment above, as shown in FIG. 5 , the second single-phase unit 20 further includes: a voltage regulating switch 208 .

The voltage regulating switch 208 is a three-phase on-load voltage regulating switch, and the three phases of the voltage regulating switch 208 are respectively connected with the high voltage coil and the voltage regulating coil of the first single-phase unit 10, and connected with the high voltage coil and the voltage regulating coil of the second single-phase unit 20. The voltage regulating coil is connected, and is connected with the high voltage coil and the voltage regulating coil of the third single-phase unit 30. The voltage regulating switch 208 is used to adjust the number of turns of the voltage regulating coil in the three single-phase units to adjust the three single-phase units. The high voltage output of the high voltage coil in the phase unit.

Specifically, the three phases of the voltage regulating switch 208 are respectively connected to the first high voltage coil 104 and the first voltage regulating coil 105 of the first single-phase unit 10, and to the second high voltage coil 204 and the second phase of the second single-phase unit 20. The voltage regulating coil 205 is connected, and is connected with the third high voltage coil 304 and the third voltage regulating coil 305 of the third single-phase unit 30. The voltage regulating switch 208 is used to adjust the turns of the voltage regulating coils in the three single-phase units. number to adjust the high-voltage output of the high-voltage coils in the three single-phase units.

In the three-phase combined transformer provided by the embodiment of the present invention, by setting a voltage regulating switch in the second single-phase unit, the voltage regulating switch is used to adjust the number of turns of the voltage regulating coil in each single-phase unit, and then adjust the corresponding single-phase High voltage output from the high voltage coil inside the unit.

Further, in the three-phase combined transformer provided in the above embodiment, as shown in FIG. 5, the first single-phase unit 10 and the second single-phase unit 20, the second single-phase unit 20 and the third single-phase unit 30 are respectively They are connected to each other through two corrugated tubes 40, one of which is a channel for the medium voltage star connection lead wire and the low voltage angle connection lead wire, and the other bellows tube is the channel for the high voltage star connection lead wire.

Bellows refers to a tubular elastic element connected by foldable corrugated sheets along the folding and stretching direction. The bellows are used to connect the single-phase units to serve as the channel for the oil circuit and the electric circuit between the single-phase units.

Due to the large difference between the high voltage and low voltage of the transformer, the single-phase units are generally connected through two bellows, one of which is the channel for the medium voltage star connection lead and the low voltage angle connection lead, and the other is the high voltage star connection. The channels for connecting the lead wires ensure the reliability of the transformer.

It is worth noting that the number of bellows in this embodiment can be set according to the actual situation. Generally speaking, two bellows are used to connect single-phase units, so that the high voltage and low pressure can be transmitted separately, and the continuous The complexity of the line simplifies the design of the three-phase combined transformer.

Optionally, the bellows 40 is a metal bellows.

Metal bellows is a regular wavy pipe with corrosion resistance, clean and beautiful appearance, high pressure bearing capacity and high and low temperature resistance, and long service life. It is widely used for connecting equipment and equipment. The utility model adopts the metal bellows to connect the single-phase units, realizes the connection of the three-phase low-voltage coils into a delta connection, and furthermore, the three-phase combined transformer meets the requirement of high impedance.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present utility model, and are not intended to limit it; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand : It can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements to some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the embodiments of the present utility model Scope of technical solutions.

Claims (7)

1. a three-phase combined transformer, including three single-phase unit being sequentially connected with, described three single-phase unit respectively the first single-phase unit, the second single-phase unit and the 3rd single-phase unit, it is characterized in that, each described single-phase unit includes from inside to outside successively: iron core, low-voltage coil, intermediate voltage winding, high-tension coil and voltage regulation coil；

Described second single-phase unit, also includes: three single-phase reactors, and described three single-phase reactors are connected with the low-voltage coil in described three single-phase unit respectively。

2. three-phase combined transformer according to claim 1, it is characterised in that described second single-phase unit, also includes: three low pressure extraction tubes；

Described three low pressure extraction tubes are connected with the low-voltage coil in described three single-phase unit respectively, and described three low pressure extraction tubes are for drawing three low voltage outlet terminals of described three single-phase unit。

3. three-phase combined transformer according to claim 1, it is characterised in that the iron core in each described single-phase unit is single-phase three rod structures。

4. three-phase combined transformer according to claim 3, it is characterized in that, iron core in each described single-phase unit all includes: stem stem, iron yoke and be arranged on the other post of described stem stem both sides, and described stem stem, described iron yoke and described other post are fixed together by folder；

The outside of described stem stem is disposed with described low-voltage coil, medium pressure coil, described high-tension coil and described voltage regulation coil from inside to outside。

5. three-phase combined transformer according to claim 1, it is characterised in that described second single-phase unit, also includes: tap changer；

Described tap changer is three-phase on-load voltage regulating switch, high-tension coil and the voltage regulation coil being connected with described second single-phase unit is connected three of described tap changer with the high-tension coil of described first single-phase unit and voltage regulation coil respectively mutually, and be connected with high-tension coil and the voltage regulation coil of described 3rd single-phase unit, described tap changer, for regulating the number of turn of the voltage regulation coil in described three single-phase unit, to regulate the High voltage output of the high-tension coil in described three single-phase unit。

6. the three-phase combined transformer according to any one of Claims 1 to 5, it is characterized in that, described first single-phase unit is connected with each other respectively through two corrugated tubes with described second single-phase unit, described second single-phase unit and described 3rd single-phase unit, one of them described corrugated tube is middle pressure Y-connection lead-in wire and the passage of low pressure corner connection lead-in wire, and corrugated tube described in another one is the passage of high pressure Y-connection lead-in wire。

7. three-phase combined transformer according to claim 6, it is characterised in that described corrugated tube is metal bellows。