JPS61179514A - Single-phase on-load tap changing transformer - Google Patents

Abstract

PURPOSE:To miniaturize a large capacity transformer having a large percent impedance between windings, by using a single-phase and five-leg core for constructing a single-phase on-load tap changing transformer. CONSTITUTION:A single-phase and five-leg core having three principal legs C1, C2 and C3 and two side legs is employed for constructing a transformer. Secondary windings L1, L2 and L3 are separately mounted on the principal legs C1, C2 and C3, respectively, and are connected in parallel. High-tension primary windings H1, H2 and H3 are also mounted, respectively, and two of the primary windings H1 and H2 present close to the primary terminal U on the line side are connected to each other in parallel while these are connected to the other primary winding H3 in series. Primary tap windings Tw1 and Tw2 associated with the primary windings H3 on the neutral point side are disposed in the same outermost side of the principal leg C3 such they are changed over by tap switches TC1 and TC2. Ternary windings T1 and T2 are disposed on the innermost side of the principal legs C1 and C2 on the line side, respectively, and these are connected to each other in parallel to be led to ternary terminals (a) and (b).

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a single-phase load tap-changing transformer, in particular, a primary winding, a primary tap winding, a secondary winding, and a tertiary winding in the main leg of an iron core. The present 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 in general, multiple single-phase transformers are combined to form a three-phase configuration due to transportation issues. These single-phase transformers in power transmission systems have tap windings for voltage adjustment, and are adjusted to a predetermined voltage by switching the taps using a load tap changer.

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 quality of the transformer, it is necessary to increase the relative impedance between the tertiary winding and the primary winding or between the secondary winding (especially between the tertiary and secondary winding). This is because as the capacitance of a device increases, its ohmic impedance, which must be kept above a certain value, decreases, making it difficult to limit the short-circuit capacity on the tertiary side.

Generally, in a core type transformer, the following methods are available to increase the impedance between the tertiary winding and each other winding. In other words, when arranging the tertiary, secondary, and primary windings in order from the inside of the core near the main leg,
A method of adjusting the insulation distance between the secondary winding and the secondary winding, a method of arranging the secondary, primary, and tertiary windings from the inside in the order of the main leg of the iron core, or a method of installing an axle separately. There is. However, in the first method, each winding, especially the primary and secondary
Either the diameter of the next winding becomes large, making it impossible to manufacture the transformer economically and causing transportation problems, or the impedance becomes extremely large due to size constraints. do not have. In addition, in the @2 method, the overall dimensions of the winding are small, 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 between the primary and tertiary windings must be increased. It becomes difficult to draw out the lead wires and insulate them. Furthermore, the third method requires a separate glue handle, which is difficult and uneconomical to manufacture.

For this reason, for single-phase transformers with windings that require a large chain 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-changing transformer shown in Fig. 1,
Using a single-phase four-leg configuration iron core 10 having two main legs C+ and C2 and two side legs S1 and S2, each of the main legs at,
Secondary windings L+ and Lx are placed inside each C2vC and connected in parallel to form secondary terminals u, on the line side and neutral point side.
o, the primary windings H+ and Hz are arranged outside these, and they are connected in series.
It is designed to reach the top terminal U, 0. In this case, the tertiary winding T is placed only on the main leg Cm side where the primary winding H2 on the neutral point side is located, and the 3 sending terminals a and b are drawn out, thereby creating a gap between the windings and other windings. The impedance can be increased, and the primary winding on the neutral point side H! The primary tap winding Two is connected in series with the primary tap winding Two.

When Two is installed on the main landing gear Cz, the diameter of the entire winding becomes a dog, and due to transportation limitations, the dimension between the secondary winding L2 and the tertiary winding T cannot be increased, and the chain impedance cannot be set to the specified value. In order to prevent this, tap changers TC+ and TC are placed on one side leg S2 together with the excitation winding E connected in parallel with the tertiary winding T.
It is configured to be switched by x. (Unexamined Japanese Patent Publication No. 53
In the method shown in Fig. 1, the primary tap winding Twt+Tw2 and the excitation winding E are insulated to increase the chain impedance. It is necessary to arrange the coils after forming them into a circular shape using a material or non-magnetic material, which is not easy to manufacture and increases the overall size.More importantly, the primary tap winding TwI
, Twz, each main landing gear C1, C
The capacity on the m side will increase or decrease, and the tap changer TCz
, TCs, the chain impedance between the primary and secondary windings changes significantly, resulting in a disadvantage that the utilization rate of the transformer deteriorates.

In order to avoid the above-mentioned drawbacks, in the one shown in FIG.
t, Hz and the secondary winding wire, Ll is arranged to make a predetermined connection, and connected to the primary winding on the main landing gear C2 where the primary winding H3 on the neutral point side is located, The primary tap winding Tw, which is switched by the tap changer TC, is disposed, and the tertiary winding T is disposed on the outermost side of the tap winding Tw.
This method increases the impedance by increasing the size between the next windings. (Refer to Japanese Unexamined Patent Publication No. 51-4528.) In the method shown in Fig. 2, a high voltage will be generated at the end of the primary winding H1 on the neutral point side, and the primary tap winding Tw will be 3 Since it is located inside the next winding T, it has drawbacks such as difficulty in drawing out the tap lead wire. In addition, in this case, if the transformer has a large capacity, it is necessary to divide the current by connecting two circuits in parallel to take into consideration the capacity of the load tap changer used, but this division uses the upper and lower ends in parallel. The primary winding H on the line side
The upper and lower ends of 1 must be routed as they are and connected separately to the primary winding H2 on the neutral point side made of two parallel conductors.
Since the next tap winding Tw is also a parallel circuit, there is a drawback that the number of lead wires also increases.

[Purpose of the invention]

The purpose of the single-phase on-load tap-changing transformer of the present invention is to miniaturize a high-voltage, large-capacity transformer with a large chain impedance between each winding so that it can be easily manufactured, and also to make it possible to easily manufacture a transformer with large chain impedance between each winding. The goal is to reduce

[Summary of the invention]

In the present invention, an iron core with a single-phase five-leg configuration having three main legs and two side legs is used, and when arranging primary, secondary, and tertiary windings as well as primary tap windings on each main leg, , the tertiary winding is placed on the main landing gear where the primary winding on the track side is located, and the primary tap winding is placed on the main landing gear where the primary winding on the neutral point side is located. It is characterized by

[Embodiments of the invention]

Hereinafter, the present invention will be explained using the embodiments shown in FIGS. 3 and 4, in which the same parts as the conventional ones are given the same reference numerals. The figure shows two main landing gears C1, C2, Cs and two side landing gears (
Main leg C
+, C2, and Cs respectively have secondary windings L+, Lx,
Ls are placed separately and connected in parallel, and a high voltage primary winding H1, Hz.

H3 is also arranged, and the two primary windings Hs and Hz close to the primary terminal U on the line side are connected in parallel, and these are connected in series with the remaining primary winding Hs. It is something to do. 1 connected to the primary winding H1 on the neutral point side
The next tap winding Tv++TW2 is arranged on the outermost side of the same main landing gear C3 and is switched by tap changers TC1 and TCz. In each of the main legs C+ and Cm on the track side, tertiary windings T+ and T2 are arranged on the innermost side, respectively, and these are connected in parallel to reach tertiary terminals a and b.

In this way, each main leg C+ of the iron core in a single-phase five-leg configuration
, C2, and Cs can each have three windings, so the winding distribution to each main landing gear CI, C2, and Cs can be optimized and made almost equal, making manufacturing easier. It can be made smaller.

In addition, in the main landing gear C1 and C2, the dimension between the secondary winding L+ and the tertiary winding T can be made sufficiently large.
The chi impedance between these is also sufficiently high. In this case, the impedance between the primary and secondary windings can be arbitrarily adjusted by increasing the dimension between the primary winding Hs, which is the neutral point side of the stage insulation, and the secondary winding L3. The distance between the primary winding Hr + Hz and the secondary winding L2 on the line side can be the minimum dimension determined for insulation reasons, so the dimensions between the secondary winding Ls and the tertiary winding T are You will have enough. Furthermore,
In this method, the primary winding H1, Hz on the line side and the secondary winding Ls
If you change the capacitance ratio between them, for example, make the capacity on the line side smaller than the capacity on the neutral side, then the line side windings HI, Hz and L+
, L2 becomes small, so that the secondary winding LI
It is also possible to adjust the impedance by adjusting the dimension between L+ and the tertiary winding T, or by placing the tertiary winding T on the outermost side and increasing the distance between it and the secondary winding L+. You can also do that.

On the other hand, in the structure of this system, the primary tap winding Tw
Since r and Tw2 are arranged adjacent to the primary winding Hs and the secondary winding Ls on the neutral point side, even when the taps are changed by the tap changers TC1 and TC, the primary and secondary windings are The chain impedance between the windings hardly changes, and the chain impedance between the secondary and tertiary windings and between the primary and tertiary windings also does not change. Furthermore, the transformer configured in this manner is suitable for increasing the primary side capacity, and since the tertiary windings Ts and Tt can be easily adjusted, it is most suitable for increasing the tertiary capacity.

Another embodiment of the present invention, shown in FIG.
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The structure is such that each winding is placed at C+, C2, and Cs,
Conversely, two primary windings H2 and H5 on the neutral point side are connected in parallel and connected in series with one primary winding H1 on the line side. In this case, the tertiary winding T is disposed at the innermost or outermost side of one main leg CI, and is used so that the chimney dance between it and other windings is sufficiently large. 1 on the outermost side of the main landing gear C2, C, on the neutral point side, respectively.
Next tap windings Tw1, Ta2 and Two, Ta4
are arranged, and the primary tap windings of these legs are connected in parallel via tap changers TC+, Te3, TCs, and Te3. In this way, by placing the tap windings on the two main landing gears and using them in parallel, and placing the tertiary winding on the other main landing gear, you can achieve the same effect as in the previous example, and also reduce the voltage of the transformer. The adjustment capacity can be significantly increased, and a tap selector with a small switching capacity can be used.

Primary tap winding Tw I+ used in the transformer of the present invention
... TW4 is shown as having two vertically improved legs on the outermost side of the same main landing gear on each side in Figures 3 and 4, but it can be used not only in this configuration, Of course, the primary winding can also be used without being limited to the upper and lower parallel configuration.

If a single-phase load tap switching transformer is constructed using a single-phase five-leg iron core as in the present invention, the tertiary winding and the primary tap winding are connected to each main leg on the line side and the neutral point side, respectively. Since windings are arranged separately in each main leg, the winding distribution on each main leg is good, and since no windings are arranged on the side legs, it is easy to downsize and easily transform a large-capacity transformer with large impedance between each winding. can be produced. In addition, 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 of the two legs are connected in parallel. 2
If the primary tap windings of the legs 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 drawings]

1 and 2 are winding layout diagrams showing a conventional single-phase on-load tap-changing transformer, respectively, and FIGS. 3 and 4 show different examples of the single-phase on-load tap-changing transformer of the present invention, respectively. FIG. C+, 02, Cs = main landing gear, H+, Hi,
Hs ・"Primary winding, L+ + L2 r Ls ・-
Secondary winding, T, Tt. Ta-tertiary winding, Twl, Ta2, Tws, T
a4...Primary tap winding. 10th mackerel 2B

Claims (1)

[Scope of Claims] 1. An iron core having a single-phase five-leg configuration having three main legs and two side legs, a secondary winding arranged in each main leg of the iron core and connected in parallel, and A primary winding arranged outside the next winding, two of which are connected in parallel and the other one connected in series, a primary tap winding connected to the primary winding, and a tertiary winding. 1, the tertiary winding being on the line side.
A unit characterized in that the primary tap winding is arranged on the main leg of the iron core where the secondary winding is located, and the primary tap winding is arranged on the main leg of the iron core where the primary winding on the neutral point side is located. Phase load tap change transformer. 2. The single-phase on-load tap-change transformer according to claim 1, wherein the tertiary windings are respectively arranged on two main legs on the line side of the iron core and connected in parallel. 3. The single-phase load tap switching transformer according to claim 1, characterized in that the primary tap windings are arranged on the two main legs on the neutral point side of the iron core and connected in parallel. vessel.