JPS586110A - Autotransformer - Google Patents

Abstract

PURPOSE:To increase the impedance of the tertiary windings by a method wherein two split parallel exciting windings are provided between the medium- voltage line terminal and the neutral terminal located between a series winding and a shunt winding and the series connection tertiary windings excited by each exciting winding respectively are provided. CONSTITUTION:A series winding 1, a shunt winding 2, and a tap winding 4 are connected in series between a high-voltage line terminal U and a neutral terminal (v). A medium-voltage terminal (u) is led out of between the series winding 1 and the shunt winding 2 and two split and parallel connection exciting windings 50a, 50b are provided between the medium-voltage line terminal (u) and the neutral terminal (v). Two split series connection tertiary windings 30a, 30b excited by the exciting windings 50a, 50b respectively are provided. Therefore, the voltage in the tertiary windings 30a, 30b wound on the same iron core legs as those for the exciting windings 50a, 50b becomes a fixed value regardless of tap position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an autotransformer having a tertiary winding. About 10 years ago, in response to the recent remarkable growth in electric power consumption, K! $00KV power transmission has started, and 100KV class power transmission is also planned in the near future. By the way, AAA transformers are used as transformers for interconnection between direct** ground systems such as these 500 KV power transmissions due to economic efficiency. Moreover, due to Japan's severe railway transportation restrictions and road trailer transportation restrictions, they are generally manufactured and transported as single-phase units, and then assembled and operated locally as three-phase banks.

FIG. 1 shows a wiring diagram of a typical autotransformer. In FIG. 1, 1 is a series winding connected to a high-voltage line terminal U, 2 is a shunt winding connected to this series winding 1 and whose connection end is connected to a medium-voltage line terminal U, and 3 is a shunt winding connected to a medium-voltage line terminal U. The secondary winding 14 connected to the tertiary terminals a and b is a tap winding whose taps are switched by a tap changer connected to the neutral point terminal V, and 5 is the excitation winding connected in a 3 km row of tertiary terminals. be. FIG. 2 shows an example of a specific 41-wire arrangement of such an autotransformer. In other words, as shown in Figure #12, the series windings 11 and 12, the shunt windings 21 and 22, and the tertiary winding 31° are connected in parallel to the two main legs 71 and 72 of the single-phase GG* iron core. and tap winding 4 on leg 8,
Tertiary person f/M31. An excitation winding 5, which is drawn in parallel with broken lines, is wound around the blade.

In such an autotransformer, the voltage of the high voltage line terminal U can be varied by keeping the voltage of the medium voltage lI circuit constant and changing the tap position of the tap IIklIi4.

However, in a transformer with this connection, the voltage of the excitation winding 5 is also low, and although it has the advantage that the winding configuration is relatively simple, the voltage at the high voltage line terminal U is varied by changing taps on the neutral point side. In this case, since the excitation of the iron core changes depending on the tap position, there is a drawback that the tertiary tide voltage also changes.

For example, the 500/VTKV-275 actually used
In the case of /, /TKV single-phase single-turn transformer with tertiary winding, each voltage ratio of the high voltage line terminal U1 medium voltage line terminal at the highest tap, rated tap, and lowest tap is 52'1. '1/JT
KV-275/ffKV, 500/n KV-271
! 1%ff KV.

4rr, 7Jr KV-zys/ff KV Tonatsur Iru, the tertiary voltage is 73.5 at the rated voltage.
For KVo, the maximum, rated, and minimum taps are 826.
KV, 73.5KV, @6.2 KV, which changes significantly.

Generally, the tertiary terminals a and bK are connected to capacitors or actuators to perform an invalid torque 111i.
As mentioned above, if the terminal voltage varies greatly depending on the tap position, the utilization rate of the capacitor etc. decreases. Problems such as reactive power control becoming multiple MJCs arise.

A method has been proposed in which a voltage change in the tertiary winding 3 is compensated for by a voltage change in the series transformer 6 by exciting the tap winding.

However, in practice, this method has not yet been adopted because it requires a separate series transformer, which increases the installation space, and complicates the wiring, impairing the reliability of the equipment.

Just like Jin, the single II has neutral point side tap switching! Transformers have the disadvantage that the tertiary voltage changes depending on the tap position, making the operation of the equipment complicated.

The present invention addresses the above-mentioned drawbacks and aims to provide a single-phase single-turn transformer with a tertiary winding in which the secondary voltage does not change due to taps and the impedance of the tertiary winding does not become small. do.

The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 4 is a wiring diagram for explaining the present invention, in which a series winding 11, a shunt winding 2, and a tap winding Is4 are connected in series between a high voltage line terminal U and a neutral point terminal M. Series winding 1 and shunt winding 2
Pull out the medium voltage line terminal U from between the
Excitation windings 50m and 50b, which are divided into two and connected in parallel, are connected between the neutral point terminal and the neutral point terminal. It is constructed by providing tertiary windings 30a and 30b which are each excited by these excitations 4)laBoa and 50b, and which are divided into two and connected in series.

FIG. 5 is a diagram showing the winding arrangement of an autotransformer having the above-mentioned wiring connection, in which a series winding 1 and a shunt winding 2 are wound around the first main leg n of a single-phase four-legged iron core. One side 30a of the secondary winding which is divided into two and connected in series to the second main leg n, one side 50a of the excitation winding which is divided into two and connected in parallel, and the tap winding 4 are wound on the side leg. The remaining one 3 of the tertiary winding divided into 8 parts
0b and the other half of the excitation winding divided into two, 50b, the tap winding 4 was connected in series with the neutral point side of the shunt winding a2, and the excitation winding m 50m and 50b were connected in series. The shunt winding is constructed by connecting both terminals u and v of the 2% tap winding 4 in parallel.

In this case, 30 m of tertiary winding wound around the main leg 72 of turtle 2
and excitation winding 150m and tap winding m4 on core side leg 8KI*
L, conversely, the tertiary winding 30b and the excitation winding 50b wound around the core side leg 8 can also be wound around the second main leg n.

Also, eat each winding 1.2 of the series and shunt to the main leg of the iron core,
One side leg 73 of the iron core is wound with one side 30a of a tertiary winding which is divided into two and connected in series with each other, and one side 50a of an excitation winding which is divided into two and connected in parallel with each other.
The remaining one of the divided tertiary windings 30b, the remaining one of the two divided excitation windings 50b, and the tap 4fIa4
It can also be configured by wrapping.

Furthermore, as shown in Fig. 6, the shunt winding is divided into two winding parts 4.22 on the medium voltage line terminal side and the neutral point side, and the shunt winding part n on the medium voltage line terminal side is wound in series. It is also possible to arrange it outside the line 1 and arrange the other neutral point terminal side shunt feeding line section 21 inside the series line 1. In addition, shunt winding 4.2
2 may be connected in correspondence with the circuit of the tap winding fa41 wound in a two-circuit configuration, or may be connected to the tap winding in a - circuit configuration.

Furthermore, both series and shunt windings 1.2 may be wound in parallel around the two main legs. In this case, the tap winding is connected in a two-circuit configuration using an even number of wires in correspondence with two shunt windings, and connected in correspondence with two or more switching switches of the on-load tap changer. Alternatively, if the on-load tap changer has a large capacity, the shunt windings may be connected in parallel and connected to the tap winding of one circuit configuration.

Next, the effects of the autotransformer according to the present invention configured as described above will be explained. The voltage at the middle terminal (voltage between u and y) is constant at zy, s/J KV, and the voltage at the high voltage terminal (
Let us consider, for example, the case where the upper and lower limits (U, machining voltage) are varied with a difference of 50A3KV. Excitation windings 59a, 50k)
Since the voltage between both ends u and v is constant, the excitation of the core leg 72.8 around which the excitation windings 50a and 50b are wound does not change depending on the tap position. Therefore, the excitation winding 5
The voltage of the tertiary windings 30a and 30b wound around the same core legs 72.8 as those of 0a and 50b is also constant regardless of the tap position. Similarly, the induced voltage of the tap winding 4 or 41 is also constant, but the induced voltage of each winding at the maximum, rated, and minimum tap positions is determined as shown in Table 1. FIG. 7 shows the wiring at the highest tap.

As can be seen from Table 1, unlike the early stage pressure regulators up to Cn, the induced voltage in the tap winding 4 or 41 is constant, so the step voltage is also constant, and the voltage change widths on the positive and negative sides are also the same. This makes it easier to control the transformer.

Furthermore, compared to the conventional measure shown in FIG. 3, a series transformer is not required, so the wiring and configuration are simplified.

Further, in the autotransformer of the present invention, one of the tertiary windings 30m and 30b (which are divided into two and connected in series) is wound around the core side leg 8. The cross-sectional area of the side leg 8 is the same as that of the main leg, and the induced voltage per winding is also %, so compared to the case where the tertiary winding and excitation winding are wound around the main leg, the winding on the side leg is smaller. In this case, the impedance between the tertiary winding and the excitation winding will be quadrupled.

Therefore, in the autotransformer of the present invention, the tertiary windings 30a, 3
The impedance between 0b and the other line becomes thicker, and the capacity of the breaker installed on the tertiary side of the transformer can be reduced.

Also, since the tertiary windings 30m and 30b are not wound on the same core leg as the shunt and series windings, the two shunts and series windings in Figure 2 are concentrated on only one leg as shown in Figure 5. Even when winding is carried out, the diameter of the winding does not increase excessively and it can often be manufactured within the transport limit. If the capacity becomes large, the shunt and series windings can be divided into two legs and wound to keep the winding diameter to the required value.

Alternatively, using the shunt shown in the gs diagram, concentrating each winding in series on only one leg will result in too large an impedance, or dividing the current flowing through the tap changer into two circuits to reduce the capacity of one switch. If it is desired to use a tap changer with a small size, the configuration shown in FIG. 6 may be used.

The excitation of the core differs depending on the leg of the core, but this is not a problem as long as the yoke between the two side legs is configured so that the magnetic flux easily passes (for example, with a three-phase five-legged core, etc.) This has already been achieved.

As described above, according to the present invention, the tertiary voltage can be kept constant regardless of changes in the tap position, and the tertiary winding has a large impedance, and it is possible to obtain a small and inexpensive autotransformer.

Furthermore, it has the advantage that the electromotive force and step voltage of the tap 1 do not change depending on the tap position as in the prior art and can be kept constant.

It should be noted that, for example, the winding arrangement of the core leg around which the tertiary winding is wound is not limited to that shown in the drawings, but may be any other arrangement such as the tertiary winding, tap 4Hi+, excitation winding -, etc. Not even.

[Brief explanation of the drawing]

Figure 111 is a wiring diagram of a conventional 500KV single-phase autotransformer.
Figure 2 is a configuration diagram showing the winding arrangement of the autotransformer shown in Figure 1, and Figure 3 is a conventional autotransformer that uses a series transformer to keep the tertiary voltage constant regardless of the tap position. FIG. 4 is a wiring diagram showing an embodiment of the autotransformer according to the present invention. FIG. 5 is a configuration diagram showing an example of the winding arrangement of the autotransformer according to the present invention. The figure is a block diagram showing another example of the winding arrangement of the autotransformer according to the present invention, and Figure 7 is a wiring diagram showing the main parts of the connection at the highest tap of the autotransformer according to the present invention. 1.12--Series 4Im, 2.22-Shunt winding 3, 32, 30a, 30b, ,-Tertiary winding 4
・・・・・・・・・・・・ Tap winding 5, shi, 50b
・・・・Excitation・Matai 6 ・・・・・・・・・・・・Series transformer 71, 72・
・・・・・・ Core main leg 8 ・・・・・・・・・ Core side leg U ・・・・・・・・・ High voltage line terminal U ・・
...... Medium voltage line terminals a, b...
・・Tertiary terminal V ・・・・・・・・・・・・ Neutral point terminal X ・・・
・・・・・・・・・ Connection between the shunt winding and the winding knob. (7317) Agent: Patent attorney Noriyuki Chika (41 years old) 1 person Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] (1) A connection between a high-voltage line terminal and a neutral point terminal, a series winding, a shunt winding, and a tap winding connected to the column, and The excitation winding is connected between the medium voltage line terminal pulled out from between the windings and the neutral point terminal, and is divided into eight parts and connected in parallel, and each excitation winding of A is excited and divided into two parts. the series winding and the shunt winding are wound around at least one #11 iron core leg; one of the excitation windings and one of the tertiary windings; the tap **, the other of the excitation winding and the tertiary iIk#
A todoroki autotransformer in which the other of the first core legs is equipped with second and third core legs KIIk each different from the first core leg. An autotransformer according to claim 1, characterized in that: (3) Claim 1, characterized in that the first core leg and the third core leg are main legs of one core, and the second core leg is a side leg of the core. The autotransformer described. (4) Claim 1, characterized in that the first core leg and the third core leg are the main leg and side leg of one core, and the 1Hz core leg is a separate core. autotransformer. (5) The shunt winding is divided into two parts, one on the medium-voltage line terminal side and one on the neutral point, and the shunt winding on the medium-voltage line terminal side is arranged externally or internally of the series winding, A single winding according to claim 1 or 2, or 3 or 4, characterized in that the neutral point side shunt winding portion is disposed inside or outside the series winding. transformer.