JPH0260044B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a single-phase load tap-change transformer, particularly a primary winding, a primary tap winding, a secondary winding, and a tertiary winding of the main leg of an iron core. This invention relates to a single-phase on-load tap-change transformer configured by arranging wires.

[Background of the invention]

Transformers used in ultra-high voltage power transmission systems are becoming larger and larger in capacity, and generally, due to transportation problems, multiple single-phase transformers are combined to form a three-phase configuration. Single-phase transformers in these power transmission systems have tap windings for voltage regulation.
Tap switching is performed using a tab switching device during load to adjust the voltage to a specified level.

For example, when such a transformer is equipped with a tertiary winding for the power supply in a substation, it is necessary to reduce the breaking capacity of the tertiary circuit breaker, and to consider the mechanical force in the event of a short circuit, making it difficult to operate the system. In order to improve the performance, it is necessary to increase the % impedance between the tertiary winding and the primary winding or between the secondary winding (particularly between the tertiary and secondary winding) of the transformer. This is because as the capacity of a transformer increases, its ohmic impedance, which must be kept above a certain value, decreases,
This is because it becomes difficult to limit the short-circuit capacity on the next side.

Generally, in a core type transformer, the following method is available as a means for increasing the percentage impedance between the tertiary winding and each other winding. That is,
Starting from the inside of the core near the main leg, tertiary, secondary, first
A method of adjusting the insulation distance between the tertiary winding and the secondary winding when placing the secondary winding, or placing the secondary, primary, and tertiary windings in the order from the inside on the main leg of the iron core. There are two methods: one method is to install a reactor separately. However, in the first method, the diameter of each winding, especially the primary and secondary windings, becomes large, making it impossible to economically manufacture the transformer, causing transportation problems, and limiting the size of the transformer. Impedance cannot be made extremely large. In addition, in the second method, the overall dimensions of the winding are smaller, but when the primary winding is at ultra-high voltage, the insulation dimension between the primary and tertiary windings must be increased, and moreover, the insulation dimension to the high voltage terminal is increased. It becomes difficult to draw out the lead wires and insulate them. Furthermore, the third method requires a separate reactor, so
It is difficult and uneconomical to manufacture.

For this reason, for single-phase transformers with windings that require a large impedance, it has been proposed to configure them as shown in Figures 1 and 2 instead of the above-mentioned methods, which have various problems. ing.

That is, in the single-phase on-load tap switching transformer shown in Fig. 1, two main legs C ₁ and C ₂ and two side legs S ₁ and S ₂ are used.
A single-phase four-leg iron core 10 is used, and secondary windings L ₁ and L ₂ are arranged inside each of the main legs C ₁ and C ₂ and connected in parallel to the line side and neutral point side. 2
Connect the primary winding to the secondary terminals u and o, and connect the primary winding to the outside of these terminals.
H ₁ and H ₂ are arranged and connected in series to reach the primary terminals U and O between the lines and on the neutral point side. In this case, 1 on the neutral point side of the tertiary winding T
Place it only on the main landing gear C ₂ side where the next winding H ₂ is located.
The secondary terminals a and b are pulled out, thereby increasing the % impedance between them and other windings, and the primary tap connected in series to the primary winding _H2 on the neutral point side. When the windings T _w1 and T _w2 are installed on the main landing gear C ₂ , the diameter of the entire winding becomes large, and due to transportation limitations, the dimension between the secondary winding L ₂ and the tertiary winding T cannot be increased, and the % impedance In order to prevent the inability to reach a predetermined value, a tap changer TC ₁ , which is placed on one side leg S ₂ together with an excitation winding E connected in parallel with the tertiary winding T, is installed.
It is configured to be switched by TC ₂ . (Refer to Japanese Unexamined Patent Publication No. 106422/1983) In the method shown in Fig. 1, primary tap windings T _w1 and T _w2 are used to increase the % impedance.
The rectangular cross section of the side leg S ₂ has to be formed into a circular shape using an insulator or non-magnetic material, and then the excitation winding E and the excitation winding E have to be arranged, which not only makes manufacturing difficult, but also reduces the overall size This has the disadvantage of increasing the current, and more importantly, when current flows through the primary tap windings T _w1 and T _w2 , the capacity of each main landing gear C ₁ and C ₂ increases or decreases by that amount. , the percentage between the primary and secondary windings is determined by the taps switched by tap changers TC ₁ and TC ₂ .
This has the drawback that the impedance changes significantly, resulting in poor transformer utilization.

In order to avoid the above drawbacks, in the one shown in FIG. 2, each main leg C ₁ , C ₂ of the iron core 10 has a
The primary windings H ₁ , H ₂ and the secondary windings L ₁ , L ₂ are arranged and connected as specified, and the primary winding H ₂ on the neutral point side
A primary tap winding T _w connected to the primary winding and switched by a tap changer TC is arranged on the main landing gear C ₂ where is located, and a tertiary winding T is arranged on the outermost side of this winding. This method increases the impedance by increasing the size between the secondary and tertiary windings. (Refer to Japanese Patent Application Laid-Open No. 51-4528.) In the method shown in Fig. 2, the primary winding on the neutral point side
A high voltage will be generated at the end of _H2 , and there are disadvantages such as it is difficult to draw out the tap lead wire when the primary tap winding _Tw is inside the tertiary winding T. In addition, in this case, if the transformer has a large capacity, it is necessary to divide the current by arranging two circuits in parallel to take into consideration the capacity of the load tap changer used, but this division uses the top and bottom in parallel. 1 on the track side
The upper and lower ends of the secondary winding H ₁ must be routed as they are and connected separately to the primary winding H ₂ on the neutral point side made of two parallel conductors, and the primary tap winding T _w must also be connected in parallel. Since it is a circuit, there is a drawback that the number of lead wires increases.

[Purpose of the invention]

The purpose of the single-phase on-load tap switching transformer of the present invention is to miniaturize a transformer with a large % impedance between each winding so that it can be manufactured easily within the transportation weight limit, and also to enable tap switching. The purpose is to reduce fluctuations in impedance.

[Summary of the invention]

In the present invention, independent cores each having a main leg and a side leg are used in the configuration of a plurality of split transformers, and the main legs of each core are provided with primary, secondary, and tertiary windings, as well as a primary tap winding. When placing the tertiary winding, place the tertiary winding on the main leg of the core where the primary winding on the line side is located, and the primary tap winding on the main leg of the core where the primary winding on the neutral side is located. It is characterized by being placed in a combination transformer.

[Embodiments of the invention]

The present invention will be described below with reference to embodiments shown in FIGS. 3 to 5, in which the same parts as those of the prior art are given the same reference numerals.

The single-phase load tap switching transformer shown in FIG. 3, which is an embodiment of the present invention, is an example constructed using two independent cores 11, and each core 11 has one main leg C _{1 .}
Alternatively, use a single-phase three-leg configuration (center core) having C ₂ and two side legs S ₁ and S ₂ or S ₃ and S ₄ , and wind each of these main legs C ₁ and C ₂ as described below. A split transformer is constituted by arranging wire groups and making predetermined connections.

That is, the secondary windings L ₁ , L _{2 and the primary windings H 1 , H 2 are arranged in combination from the inside on the main legs C 1 , C 2 of each iron core} 11, and each secondary winding L ₁ , L ₂ are connected in parallel and 2
The primary windings H 1 and H 2, located on the main legs C _{1 and} C ₂ of each core 11 and having an upper and lower parallel structure _, are connected to the primary terminal U on the line side. The primary winding H ₁ is on the side and 1 is the primary terminal 0 side on the neutral point side.
It is connected in series with the next winding _H2 . In order to increase the % impedance with other windings, the tertiary winding T is arranged at the innermost side of the main leg C ₁ of one iron core 11 where the primary winding H ₁ on the line side is located. The primary tap windings T _w1 and T _w2 connected to the primary winding H ₂ on the neutral point side of the stage insulation are arranged vertically apart from each other on the outermost side of the main leg C ₂ of the other iron core 11. The taps are selected by selectors TC ₁ and TC ₂ , respectively.

In this way, the number of windings in the main legs C ₁ and C ₂ of each iron core 11 on the line side and neutral point side that constitute the split transformer can be reduced to three, so each main leg C 1 and C 2 can have three windings. It is also possible to optimize the distribution of windings to the legs C ₁ and C ₂ so that they are approximately equal, making it easier to manufacture each split transformer and making it more compact. In addition, in the main leg C ₁ of one iron core 11, the secondary windings L ₁ and 3
Since the dimension between the next windings T can be made sufficiently large, the % impedance between them can also be made sufficiently large. In this case, the % impedance between the primary and secondary windings can be determined by increasing the dimension between the primary winding H ₂ and the secondary winding L ₂ of the split transformer, which is the neutral point side of the stage insulation. It can be adjusted arbitrarily, and between the primary winding H ₁ and the secondary winding L ₁ of the split transformer on the line side,
The secondary winding L ₁ is sufficient because it has the minimum dimensions determined by insulation.
This means that a sufficient dimension can be secured between the tertiary winding T and the tertiary winding T. Furthermore, with this method, the primary winding of the line-side split transformer
By changing the capacitance ratio between H ₁ and the secondary winding L ₁ and between the primary winding H ₂ and the secondary winding L ₂ of the neutral-side split transformer, for example, change the capacity on the line side to the capacity on the neutral side. If you make it smaller,
Since the windings H ₁ and L ₁ on the line side are small, it is also possible to adjust the % impedance by increasing the dimension between the secondary winding L ₁ and the tertiary winding T. The tertiary winding T is placed on the outermost side and the secondary winding L ₁
It can also be adjusted by increasing the distance between the two.

On the other hand, in the structure of this system, the primary tap windings T _w1 and T _w2 are arranged adjacent to the primary winding H ₂ and the secondary winding L ₂ , which are the main windings, so the tap Even with tap switching using switchers TC ₁ and TC ₂ , primary and
The % impedance between the secondary windings hardly changes, and the % impedance between the secondary and tertiary windings and between the primary and tertiary windings also does not change.
As mentioned above, the present invention involves connecting split transformers fabricated as independent structures to form a desired single-phase load tap-changing transformer. It is also easy to manufacture transformers with .

The present invention shown in FIG. 4 shows another example of a single-phase load tap-change transformer configured with split transformers.
Secondary windings L ₁ , L ₂ , and L ₃ are placed separately in C ₁ , C ₂ , and C ₃ and connected in parallel, and high-voltage primary windings H ₁ , H ₂ , and H ₃ are also connected in parallel. The two primary windings closest to the primary terminal U on the line side
Connect H ₁ and H ₂ in parallel and connect this to the remaining 1
It is configured by connecting in series with the next winding _H3 .
Primary tap winding connected to the next winding _H3 on the neutral point side
T _w1 and T _w2 are arranged on the outermost side of the same main landing gear C ₃ and are switched by tap changers TC ₁ and TC ₂ . The tertiary windings T ₁ and T ₂ are arranged on the innermost side of each of the main legs C ₁ and C ₂ on the track side, and these are connected in parallel to reach the tertiary terminals a and b. .

A transformer configured with a plurality of divided transformers in this way can achieve the effects of the above example, and is suitable for increasing the capacity on the primary side.
Since it is easy to adjust T ₁ and T ₂ , it is ideal for increasing the tertiary capacity.

The cores used in Figure 4 above include a combination of two cores: a single-phase 4-leg configuration used for the line-side split transformer and a single-phase 3-leg configuration used for the neutral-side split transformer, and There is a combination of three iron cores in a phase three-leg configuration, and each main leg can be configured by arranging each winding as shown in the figure.

These iron cores can be used appropriately depending on the manufacturing conditions, transportation conditions, etc. of the transformer, so manufacturing can be facilitated.

Another embodiment of the present invention, shown in FIG. 5, has a structure in which windings are arranged on three main legs C ₁ , C ₂ , and C ₃ to form a split transformer, similar to that in FIG. 4. However, on the contrary, two primary windings H ₂ and H ₃ on the neutral point side are connected in parallel and connected in series with one primary winding H ₁ on the line side. In this case, the tertiary winding T is placed at the innermost or outermost side of one main leg _C1 ,
It is used by making the % impedance between it and other windings sufficiently large. Main landing gear C ₂ on the neutral point side,
On the outermost side of C ₃ are primary tap windings T _w1 ,
T _w2 , T _w3 , and T _w4 are arranged, and tap changers TC ₁ , TC ₂ ,
Used by connecting in parallel via TC ₃ and TC ₄ . In this way, by placing the tap windings on each of the two main landing gears and using them in parallel, and placing the tertiary winding on another main landing gear, the same effect as in the previous example can be achieved, and
The voltage adjustment capacity of the transformer can be significantly increased, and a tap selector with a small switching capacity can be used.

In the example shown in FIG.
Leg iron cores can be used as appropriate.

The primary tap winding T _w1 used in the transformer of the present invention,
...T _w4 is shown as having two vertically opposed upper and lower outermost parts of the same main landing gear in each embodiment of the figure, but it can be used not only in this configuration, and the next winding can also be configured in upper and lower parallel configurations. Of course, it can be used.

When the single-phase load tap-changing transformer of the present invention is configured, the tertiary winding and the primary tap winding are arranged separately on the main legs of the line-side and neutral-side split transformers, respectively. Since the split transformer has good winding distribution and no windings are arranged on the side legs, a transformer with a large % impedance between each winding can be easily manufactured by combining the split transformers. In addition, since a transformer is manufactured by combining multiple split transformers, it is easy to manufacture a transformer that meets transportation conditions. In this case, the primary windings of the two main legs are connected in parallel, and the other primary windings are connected in series, and the tertiary windings placed in parallel on the two legs are connected in parallel.
Alternatively, if two primary tap windings are connected in parallel and used, a transformer with a larger capacity can be constructed, and the tertiary capacitance or voltage adjustment capacitance can be easily adjusted.

[Brief explanation of the drawing]

1 and 2 are winding layout diagrams showing conventional single-phase load tap-changing transformers, respectively, and FIGS. 3 to 5 each show different examples of the single-phase load tap-changing transformer of the present invention. FIG. 10, 11... Iron core, C ₁ , C ₂ , C ₃ ... Main landing gear,
S ₁ , S ₂ , S ₃ ... Side leg, H ₁ , H ₂ , H ₃ ... Primary winding, L ₁ , L ₂ , L ₃ ... Secondary winding, T, T ₁ , T ₂ ……
Tertiary winding, T _w1 , T _w2 , T _w3 , T _w4 ...Primary tap winding.

Claims (1)

[Scope of Claims] 1. An iron core having main legs and side legs used in the configuration of a plurality of divided transformers, and 2. A secondary winding, a primary winding arranged outside the secondary winding and connected in series, a primary tap winding connected to the primary winding, and a tertiary winding, The tertiary winding is arranged on the main leg of the core where the primary winding of the line-side split transformer is located, and the primary tap winding is located on the main leg of the core where the primary winding of the neutral-side split transformer is located. A single-phase load tap-change transformer, characterized in that it is configured by being placed in the main leg of a. 2. The tertiary winding is arranged at the innermost side of the winding group located on the main leg of the iron core of the line-side split transformer, and
At the time of a single-phase load according to claim 1, the next tap winding is arranged at the outermost side of the winding group located on the main leg of the core of the neutral point side split transformer. Tap switching transformer. 3. The iron core of each split transformer is one main leg and two
A single-phase on-load tap-change transformer according to claim 1 or 2, characterized in that it has a single-phase three-leg configuration having two side legs. 4. The iron core of each split transformer has one main leg and two
The single-phase load according to claim 1 or 2, characterized in that the load has a single-phase three-leg configuration having two side legs and a single-phase four-leg configuration having two main legs and two side legs. Time tap switching transformer. 5. The single-phase on-load tap-change transformer according to claim 1 or 2, wherein each of the iron cores has a single-phase four-leg configuration having two main legs and two side legs. . 6. A patent claim characterized in that the primary windings are arranged on the main legs of three iron cores, two primary windings are connected in parallel, and the remaining primary windings are connected in series. Single-phase on-load tap-change transformers as described in item 3. 7. The single-phase load tap switching transformer according to claim 3, wherein the tertiary windings are arranged on the main legs of two iron cores and connected in parallel. 8. A single-phase load according to claim 4 or 5, characterized in that the primary tap windings are respectively arranged on two main legs of the iron core of one split transformer and connected in parallel. Time tap switching transformer.