JPS62104015A - Single-phase auto-transformer - Google Patents

Abstract

PURPOSE:To make small the variation in impedance due to difference of tapping position by respectively dividing the excitation winding and tap winding in two winding units, winding them to the different iron core legs, and connecting in parallel or seria the divided excitation windings and tap windings. CONSTITUTION:The one iron core leg 11 is wound with a serial winding 2, a shunt winding 3 and a tertiary winding 4; other two iron ocre legs 12 are wound with an excitation winding 51 and a tap winding 61 respectively, and the excitation windings 51 and tap windings 61 are connected in parallel. Since there are two legs for combination of the excitation winding and tap winding, the variation in an impedance between the excitation winding and tap winding, namely variation in impedance by difference of tap position can be reduced to about 1/2 of the prior case. In case the excitation winding and tap winding are connected in series, similar effect can also the obtained since a current I is the same as the prior case and the number of windings N can be reduced to 1/2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a single-phase autotransformer, and particularly to an improvement of a transformer that reduces impedance fluctuations due to differences in tap position.

[Background of the invention]

Generally, autotransformers perform voltage switching.

Although it is mostly manufactured and used as a so-called on-load tap change transformer, the capacity of the tap winding is not so small compared to the capacity of the main winding, and may be about 10 to 20 factors. In such a case, it is inevitable that the impedance will change to some extent due to a change in the tap position.

However, considering the maintenance, IJ, and other settings, it is desirable to minimize the variation in the impedance of the transformer.

An example of a method for reducing changes in impedance due to changes in tag position in an autotransformer that maintains the voltage on the high voltage side constant and changes the voltage on the low voltage side (called the fork connection method). Siemens-Zeitsch
rift 41 (1967) Heft1, )), pages 23 to 31.

``380kV single-phase single-phase pressure vessel #) consisting of 100100O
Three-phase Punk J (1000-MVA-Drehstro
mb'ankem i t 380-kV -E 1n
phasen-8partran sforma to
-ren). In this method, as shown in FIGS. 5 and 6, the tap winding 61 and the excitation winding 51 are placed on a core leg 12 different from the core leg 11 on which the shunt winding 3 and the series winding 2 are wound. By appropriately devising the winding and excitation winding connections.

The current distribution flowing through the shunt winding 3 and the series winding 2 is prevented from changing due to a change in the tap position. As a result, changes in the Innov dance due to changes in the tap position are
The only change in impedance is between the tap winding 61 and the excitation winding 51, and the change in impedance is relatively small. However, even with this method, the change in innovidance due to a change in tap position is reduced to only a change K that is approximately the same as the rate during voltage adjustment. In other words, if the voltage adjustment is 10 width, the impedance is also 1
It changes by about 01.

[Purpose of the invention]

An object of the present invention is to provide a single-phase autotransformer in which fluctuations in impedance due to differences in tap positions are reduced.

[Summary of the invention]

The feature of the present invention is that the excitation winding and the tap winding are each divided into two winding units and wound on different iron core legs, and the divided excitation windings and tap windings are connected in parallel or in series. There is a particular thing.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. An example of a fork-connected single-phase autotransformer will be explained below. In this embodiment, a series winding 2 is connected to one core leg 11.
The first shunt winding 3 and the tertiary winding 4 are wound on the other two core legs 12, and the excitation winding 51 and the tap winding 61 are wound on the other two core legs 12.
are respectively wound, and the excitation windings 51 and the tap windings 61 are connected in parallel and tangent to each other. Figure 2 shows the winding connections. Note that the tertiary winding 4 is not related to the explanation, so the second
Not shown in the diagram.

The reason why the present invention can reduce the change in impedance due to the difference in tap position will be explained below with reference to FIG. As mentioned above, by devising the connection of the excitation winding 51 (in the case of fork connection, connect it in parallel with the shunt winding), the current distribution of the series winding 2 and the shunt winding 3 can be adjusted depending on the tap position. It can be prevented from changing by Therefore, the impedance variation is only between the excitation winding 51 and the tap winding 61. The bar 7 toy 7 beadance between the excitation winding 51 and the tap winding 61 is calculated by the following equation.

(However, 1-minute is shown) However, here f: Frequency N: Number of turns of excitation winding r: l *Flow P: Rated capacity of transformer Dε: Width of excitation S winding r) G: Distance between windings DT: Width of tap winding Rt: Average radius of excitation winding Ro: Average radius of gap between windings RT: Average radius of tap winding In this example, two excitation windings are tangent in parallel. Therefore, compared to the conventional example shown in FIG. 5, the number of turns N is the same, but the current ■ is 1/2. Therefore.

Even if we assume that Δ is the same (actually, Dg and DT in the winding can be made smaller, so Δ will be smaller than in the conventional example)
, %Vz of one leg is (1/2)! = 1/4. In other words, in this embodiment, the combination of excitation winding to tough 1 winding is 2.
Because of the presence of the legs, the innovidance between the excitation winding and the tap winding, that is, the change in impedance due to a difference in tap position, can be reduced to about 1/2 of the conventional example according to the present invention.

FIG. 4 illustrates how the impedance changes as the tap position changes. Curve A shows the example of the present invention, and curve B shows the conventional example.

Above, we have explained an example in which the excitation winding and the tap winding are connected in parallel, but if the excitation winding or tap winding is connected in series, the current flow is the same as in the conventional example, and the number of turns is N.
is reduced to 1/2, so a similar effect can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, in a single-phase autotransformer, changes in impedance due to differences in tap positions can be reduced.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams showing one embodiment of the single-phase autotransformer of the present invention, FIGS. 3 and 4 are explanatory diagrams for explaining the present invention in detail, and FIGS. FIG. 6 is an explanatory diagram showing a conventional example. 1.11.12... Iron core 2... Series winding, 3...
・Shunt winding, 4... Tertiary winding, 51... Excitation winding,
61...Tap winding.

Claims (1)

[Claims] 1. An iron core having at least three legs, a series winding,
In a single-phase autotransformer that has a shunt winding, a tap winding, and an excitation winding, and switches the voltage on the primary or secondary side, the series winding and the shunt winding are connected to one leg of the iron core. wrapped,
A single-phase single-winding transformer characterized in that both the excitation winding and the tap winding are wound around the other two legs, and the excitation windings and the tap windings are connected in parallel.