JPS5979514A - Autotransformer - Google Patents

Abstract

PURPOSE:To avoid the variation of the tertiary terminal voltage in accordance with the position of the tap by a method wherein the 1st series winding, a branch winding and a tertiary winding are wound around a main leg of the 1st core and at the same time the 1st exciting winding connected to the tertiary winding in parallel and a tap-winding are wound around a side leg of the core and the 2nd exciting winding and the 2nd series winding are wound around the 2nd core. CONSTITUTION:One end of the 1st series winding 7 is connected to a high voltage line terminal U and another end is connected to one end of a branch winding 8 via a series winding 14 of a series transformer 15 and at the same time connected to an intermediate voltage line terminal (u). Another end of the branch winding 8 is connected to a neutral terminal V. The 1st exciting winding 11 is connected to terminals (a) and (b) of a tertiary winding 9 so as to be in parallel to the tertiary winding 9. A tap-winding 10 is provided and connected to the 2nd exciting winding 13 via a required position of the tap. The area enclosed by a dot line 12 shows the main transformer proper and the area enclosed by a dot line 15 shows the series transformer proper. With this constitution, the terminal voltage of the tertiary winding 9 is kept constant regardless to the position of the tap of the tap-winding 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a winding transformer, and particularly to a split single-phase autotransformer.

[Technical background of the invention and its problems]

In response to the recent remarkable growth in electricity demand, Japan has also
00KV power transmission has started, and 1000KV class power transmission is also planned in the near future. Directly grounded systems are used for these ultra-high pressure power transmissions, and autotransformers are used for interconnection between the directly grounded systems from the viewpoint of red pile performance. By the way, these autotransformers are generally manufactured and transported as single-phase transformers due to strict railway transportation restrictions and road trailer transportation restrictions in Japan, and are assembled and operated locally into three-phase banks.

Figure 1 is a typical single-phase single-winding transformer diagram, in which a high-voltage line terminal U is led out from one end of the series winding 1, and the series winding lr
A medium voltage line terminal U is led out from the other end of M1 and connected to the shunt winding 2. Further, the tap winding 4 is connected to the neutral point side of the shunt winding 2 to keep the voltage at the medium voltage line terminal U constant and to vary the voltage at the high voltage line terminal U. 3 is a tertiary winding, and alb is its terminal.

In the transformer 5 shown in FIG. 1, the voltage at the high-voltage line terminal U is varied by changing the tap on the neutral point side, so the excitation rate of the iron core changes depending on the tap position, and therefore, between the terminals alb of the tertiary winding 3 The disadvantage is that the voltage of
Since the excitation rate of the core changes depending on the tap position, the core magnetic flux density at taps other than the maximum excitation tap has a sufficient margin.9 As a result, the core weight increases and the transformer as a whole becomes larger. There is also.

Taking a single-phase single-winding transformer with a tertiary winding as an example, the voltage ratio of the high tap, rated tap, and lowest tap is 1.0, and the excitation rate is 1.0 for the highest tap.If p and u are the highest tap, then for the rated tap, At the lowest tap of 0.89, it decreases to 0.80, and the utilization rate of the iron core decreases. Also, assuming that the voltage between terminal alb of the tertiary winding 3 is 63KV at the rated time, the highest and lowest taps are 70.8KV and 56.8KV, respectively.
It changes significantly to 8KV. And the terminal a of the tertiary winding 3
Generally, a capacitor or an accelerator is connected between LB and reactive power adjustment, so if the voltage changes significantly depending on the tap position as described above, the utilization rate of the capacitor etc. will decrease and reactive power control will become complicated. The problem arises. Therefore, as a method of keeping the voltage between both terminals of the tertiary winding constant and preventing the excitation of the iron core, as shown in FIG. Minute Ii is also winding 2.
A method has been found to indirectly vary the voltage of the high voltage terminal U by winding a tap wire 4 together with the tertiary winding 3 and exciting a separate series transformer 6 connected to the tap winding 4. It is being proposed. However, this method does not meet the transportation conditions in Japan, as the four windings mentioned above are arranged on the main leg of the iron core in ultra-high pressure class large-capacity propellers, which increases the diameter of the windings and increases the transportation size. It is not an appropriate method in countries with strict conditions,
There are also few actual examples.

As explained above, conventional high-voltage autotransformers have drawbacks such as fluctuations in the tertiary winding and a decrease in the core utilization rate, while indirect tap-change transformers have The drawback was that the diameter of the winding became larger and transportation restrictions became stricter.

[Purpose of the invention]

The present invention has been made to eliminate the above-mentioned drawbacks.
The purpose is to provide an autotransformer whose tertiary terminal voltage does not change depending on the tap position and which has a large capacity and is transportable.

[Summary of the invention]

In order to achieve the above object, the present invention includes winding a first series winding, a shunt winding, and a tertiary winding around the main leg of the first iron core, and winding the first series winding, the shunt winding, and the tertiary winding around the side legs of the first iron core. a main transformer body formed by winding a first excitation winding and a tap winding connected in parallel with a tertiary winding; a second excitation winding that is excited from the tap winding around a second iron core; 1'i15: of the second series winding is connected to the shunt winding to form a medium voltage line end. None, the other end of the second series winding is connected to the medium voltage terminal side which is one end of the first series winding, and the other end of the first series winding is connected to the high voltage road end. The present invention also relates to an autotransformer in which the main transformer main body and the series transformer main body are housed in separate tanks.

Example An embodiment of the present invention will be explained with reference to the drawings.

FIG. 3 is a wiring diagram of the autotransformer of the present invention, and FIG. 4 is a winding configuration diagram of the autotransformer of FIG. 3. In addition, Figures 3 and 4
In the figures, the same components are given the same reference numerals.

First, a wiring diagram of the autotransformer of the present invention will be explained with reference to FIG. As shown in the figure, one of the first series windings 1 to 7 is
7iAi is connected to the high voltage line terminal UK, and the other end is connected to one end of the shunt winding 8 via the series winding 14 of the series transformer 15, and is connected to the medium voltage line terminal U. Further, the other end of the shunt winding 8 is connected to the neutral point terminal V. The terminal of the tertiary winding 9 is aSb, and the first excitation winding 11 is provided in parallel connection with the tertiary winding 9. Furthermore, a tap winding IO is provided, and this tap winding 10 is connected to the second excitation winding 13 through a desired tap position 1. Note that dotted line 12 indicates 1
” The opening part is the main transformer body, and is surrounded by dotted line 15 81
3 minutes constitutes the series transformer body.

Next, the winding arrangement diagram of the transformer shown in Fig. 3 above is shown in Fig. 4.
The diagram will be explained. A first series winding 7, a shunt winding 8, and a tertiary winding 9 are wound around the first core main leg 16, and a first excitation winding 11 and a tap winding are wound around the core side leg 17. 10 is wound to constitute the main transformer main body 12, and the second series winding 14 and the second excitation winding 13 are wound around the second core leg 18 to form the series transformer main body 15. Configure.

Then, the main transformer main body 12 and the rM row transformer main body 15
are stored in separate tanks.

Next, the operation of the autotransformer according to the present invention will be explained.

In the connection diagram of the autotransformer shown in Fig. 3, the voltage applied between both terminals u and V of the shunt winding 8 is constant at the medium voltage side, so the excitation of the first core changes depending on the tap position. There isn't. Therefore, the terminal voltage of the tertiary winding 9 is also constant regardless of the tap position, the utilization rate of the iron core is increased, and the weight can be reduced. In addition, the high voltage 0Ill is applied to the series transformer 1 whose induced voltage changes depending on the tap position in the series winding 7 and the shunt winding 8 which induce a constant voltage.
5, the induced voltage of the series winding 14 is added, the tap winding 100'1 voltage, the two windings of the series transformer (13,
14) By selecting the turns ratio, it is possible to obtain the required voltage ratio.

Further, since the tap winding 10 is not wound around the main leg 16 of the main transformer 12, the winding diameter becomes smaller, and the transformer capacity within the transport limit can be increased accordingly.

〔Effect of the invention〕

As explained above, according to the present invention, since the terminal voltage of the tertiary winding is configured to be constant regardless of the tap position of the tap winding, the utilization rate of the transformer core is increased.
Moreover, since no tap winding is wound around the main legs of the main transformer, an autotransformer with a larger transportable capacity can be obtained.

[Brief explanation of the drawing]

Figure 1 is a wiring diagram of a conventional autotransformer, Figure 2 is a wiring diagram of a conventional autotransformer in which a series transformer is inserted into a medium voltage circuit.
FIG. 3 is a wiring diagram of an autotransformer which is an embodiment of the present invention,
FIG. 4 is a diagram showing the winding arrangement of the autotransformer shown in FIG. 3. 7.14...Old row winding, 8...Shunt winding Yc9...Tertiary winding, 10...Tag winding, 11.13...Excitation winding, 12...Transformer body, 15... Series transformer body, 16
．． 17.18... Iron core. (8733) Agent: Yoshiaki Inomata, patent attorney (and 1 others)
Figure 1 Figure 2

Claims (1)

[Claims] (L) A first series winding, a shunt winding, and a tertiary winding are wound around the main leg of the first iron core, and a first series winding, a shunt winding, and a tertiary winding are connected in parallel with the tertiary winding on the side legs of the first iron core. A main transformer main body is formed by winding a first excitation winding and a tap winding, and a second iron core is wound with a second excitation winding and a second series winding, which are excitation fields from the tap winding. one end of the second series winding is connected to the shunt winding to form a medium voltage line end, and the other end of the second m-series winding is connected to the shunt winding. connected to the medium voltage terminal side which is one end of the first series winding, and further connected to the v
, the other end of the series winding of 1 is entwined with a high voltage line, and the main transformer main body and the series transformer main body are housed in separate tanks.