JPS6161529B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a load tap switching transformer, and more particularly to a transformer equipped with a load voltage regulator (hereinafter referred to as LVR).

As power transmission systems become larger and higher in voltage, the current value required for load switching in LVRs has become significantly larger in large-capacity transformers.
If the switching current limit of the switching switch is exceeded,
It has become common practice to use two switching switches in parallel.

This will be further explained using an example of a single-phase single-winding transformer equipped with an LVR shown in FIG.
This type of transformer consists of a main transformer section 10 and an LVR section 20. And main transformer part 1
0 is a series winding 1 connected to the main leg of the iron core (not shown) to a high-voltage terminal U, and a shunt winding connected to the neutral point side of the series winding 1, and this connection point connects to a medium-voltage terminal U. 2 and a tertiary winding 3 from which tertiary terminals a and b are drawn out for use in an in-house power supply or phase adjustment equipment. Also,
The LVR 20 has a tap winding 5 connected to the neutral point side of the shunt winding 2 via a polarity switch 6 to an auxiliary core leg (not shown), and a tap winding 5 connected in parallel with the tertiary winding 3. The excitation winding 4 that excites the winding 5 is wound, and a plurality of taps drawn out from the tap winding 5 are connected to each tap selector 7 by alternately cutting off the current to the switching switch 8 of the tap changer 30 at the time of load. The on-load tap changer 30
The configuration is such that the terminal is connected to the neutral point terminal O.

By the way, the on-load tap changer 30 consists of a polarity changer 6, a tap selector 7, a changeover switch 8 and other components shown separately in FIG. 1, and the current capacity of each of these contacts is Limited due to manufacturing and functional reasons, especially switching switch 8
Since the contacts open and close when energized, the current capacity of the on-load tap changer 30 is determined by this performance. Therefore, as the capacity of transformers increases, one switching switch becomes insufficient in its breaking current capacity, so two switching switches are used in parallel. When switching switches are used in parallel in this way, there is a risk that an unbalanced current will flow between the parallel circuits due to a slight difference in the opening and closing times between these contacts, causing burnout of the contacts and current limiting resistors. To prevent this, conventional single-phase transformers have
As shown in the figure, a single-phase four-leg iron core 9 is used, the two core main legs C ₁ and C ₂ are used as the main transformer part, and one of the two side legs S ₁ and S ₂ is used as the LVR part. things are being done. As shown in Figure 3, the arrangement of the windings in this core is such that each core main leg C ₁ , C ₂ has tertiary windings 31 , 32 and shunt windings 2 from the inside, respectively.
1, 22, and the series windings 11 and 12 are arranged in order so that they are used in parallel, and the side legs that are auxiliary core legs are
C ₂ is provided with an excitation winding 4 connected in parallel with the tertiary windings 31 and 32, and tap windings 51 and 52 with a two-part structure connected to the neutral point side of each shunt winding 21 and 22. The connections of these windings are shown in FIG. In other words, two parallel windings are made with two series windings 11, 12, shunt windings 21, 22, and tap windings 51, 52, respectively, and two parallel windings are made with the main leg of another iron core.
Utilizing the leakage impedance between the shunt windings 21 and 22 by winding them around C ₁ and C ₂ , each tap of each tap winding 51 and 52 can switch taps under load. Even if the load current is cut off alternately with the two switching switches 81 and 82 of the switch 30 and the appropriate one is selected with the tap selectors 71 and 72 connected to these switches, the two switching switches 81 and 82 are connected in parallel.
We are trying to eliminate the inconvenience when using .

However, in the structure using a single-phase four-legged core as described above, each winding must be placed on each of the two core legs C ₁ and C ₂ , which has the disadvantage of increasing the size and manufacturing cost. be.

The purpose of the on-load tap-changing transformer of the present invention is to
To provide a transformer that can perform tap switching without trouble even when two switching switches are used in parallel, and can be made smaller and lighter.

In order to achieve the above object, the present invention uses an iron core having one core main leg when configuring the main transformer part and the LVR part, and at least a high voltage side winding and a low voltage side winding are connected to this core main leg. winding to form the main transformer part, an excitation winding connected to the auxiliary core leg in parallel with the low voltage side winding of the main transformer part, and a partial winding divided into two to form two parallel circuits. The LVR part is constructed so that two parallel circuits are created by winding connected tap windings, and the taps of each tap winding are switched by a load tap switch equipped with two switching switches. It is characterized by:

The on-load tap-changing transformer of the present invention will be described below with reference to FIGS. 5 to 8, in which the same parts as those of the prior art are designated by the same reference numerals.

The on-load tap-changer transformer of the present invention, as shown in FIG. 5, is comprised of a main transformer section 10 and an LVR section 20 having an on-load tap-changer 30, as in the prior art. In this example, the main transformer section 10 has a series winding 1 wound around the iron core main leg (not shown), one end of which ends at a high-voltage terminal, as in the conventional case, and a series winding 1 connected to the neutral point side to form a connection point It consists of a shunt main winding 2A leading to an intermediate voltage terminal, and a tertiary winding 3 from which tertiary terminals a and b are drawn out. The shunt main winding 2A includes two shunt partial windings 23 and 24 used in parallel, which will be described later.
The main shunt winding 2A has most of the turns of the shunt winding, and the remaining turns are made up of two parallel shunt partial windings. line 23,
24 have. The LVR portion 20 also includes a shunt main winding 2A wound around an auxiliary core leg (not shown).
The shunt partial windings 23 and 24 are connected to the neutral point side and used in parallel, and this shunt partial winding 2
Load tap changer 30 on each neutral point side of 3 and 24
Tap windings 51 and 52 used in parallel are connected via switching switches 61 and 62, which are components of It is equipped with an excitation winding 4 that excites the shunt portion windings 23 and 24 and the tap windings 51 and 52, and connects a plurality of taps of each tap winding 51 and 52 to two parallel connections of the on-load tap changer 30. The tap selectors 71 and 72 used and the switching switches 81 and 82 are used to appropriately switch and reach the neutral point terminal O.

The shunt portion windings 23 and 24 of the LVR portion 20 are
This is used to prevent damage due to the difference in operating time in the switching switches 81 and 82 used in parallel in the on-load tap changer 30, and utilizes the impedance between the shunt partial windings 23 and 24 in the two parallel configurations. In order to suppress unbalanced current in the parallel circuit, for example, when winding the shunt portion windings 23 and 24 around the auxiliary core leg, the shunt partial windings 23 and 24 may be arranged one above the other so as to face each other in the winding axis direction, or The partial windings 23 and 24 may be arranged separately inside and outside the tap windings 51 and 52, or each may be divided into a plurality of pieces and arranged alternately in the winding axis direction, or the shunt partial windings 2
The number of turns of the wires 3 and 24 is adjusted to obtain a desired impedance value.

In the transformer of the present invention, in the case of a single-phase transformer, for example, the sixth
As shown in the figure, one core main leg C and two side legs S ₁ and S ₂
A single-phase three-legged iron core 90 having a main leg C is used as a main transformer part, and one side leg _S2 is used as an auxiliary core leg to form an LVR part. This single phase three leg iron core 9
Examples of winding arrangement when using 0 are shown in Figures 7 and 8.
Shown in the figure.

In the example shown in Fig. 7, the main transformer section is constructed by winding the tertiary winding 3, the shunt main winding 2A, and the series winding 1 on the main leg C of the core in order from the inside, and making the prescribed connections. The side leg _S2 , which serves as an auxiliary core leg, includes, in order from the inside, an excitation winding 4, shunt partial windings 23 and 24 stacked in the winding axis direction, and shunt partial windings 23 and 2.
Tap windings 51 and 52 arranged in the same manner as in step 4 are wound and predetermined connections are made.
0, the taps of the tap windings 51 and 52 are simultaneously switched.

Although the above example is an autotransformer having a series winding and a shunt winding, the present invention can also be applied to a two-winding or three-winding transformer. This 2
An example of a wire-wound transformer is shown in FIG. 8, in which a medium voltage winding 102 leading to medium voltage terminals u and v and a high voltage main winding 101 are wound around the iron core main leg C to form the main transformer part. The side leg _S2 , which is an auxiliary core leg, has an excitation winding 4 as shown in FIG. 7, and high-voltage partial windings 123 and 124 that increase the impedance between the parallel windings by adjusting the winding arrangement and number of turns as described above. and tap windings 151, 152
is wound and connected in a prescribed manner to form an LVR section that switches taps with a tap changer 30 during load. It is connected in parallel with the line 102 for excitation.

In any of these single-winding, two-winding, or three-winding transformers, the LVR side constitutes two parallel circuits with partial windings 23, 24 or 123, 124 and tap windings 51, 52 or 151, 152. Therefore, by appropriately selecting the mutual impedance by setting the winding arrangement and number of windings of each partial winding, it is possible to prevent problems by using the on-load tap changer 30 that uses the changeover switches 81 and 82 in parallel. The main transformer section can be constructed using a single iron core main leg, which simplifies manufacturing and makes it possible to reduce the size and weight.

In the transformer of the present invention, the main transformer portion 10 and
The same purpose can be achieved not only when the LVR section 20 is constructed using the same core, but also when the core main leg and auxiliary core leg are configured using separate cores. Not only a transformer but also a three-phase transformer can be manufactured by using three sets of the above configuration and connecting the three phases.

Furthermore, in the above example, the two-parallel tap winding was explained as an example in which each partial winding was connected to a polarity switch.
Even if the tap winding is composed of coarse and fine tap winding parts and is connected to the partial winding through a transposition switch, it can be applied without any problems, and the winding arrangement can be done not only by stacking the windings vertically but also by stacking the windings vertically. , may also be concentric locations.

If the on-load tap switching transformer is configured as in the present invention, the main transformer section can be constructed with one iron core main leg, making it easier to manufacture and reducing the size and weight. The switching of each tap can be effected without any trouble by using a switching switch in parallel and a tap switching device at the time of load.

[Brief explanation of the drawing]

Figure 1 is a wiring diagram showing an example of a single-phase autotransformer.
Figure 2 is a front view of the contents of a conventional single-phase transformer using a four-legged core, Figure 3 is the winding arrangement diagram in Figure 2,
The figure is a detailed wiring diagram of Figure 3, Figure 5 is a wiring diagram of a single-phase autotransformer to which the present invention is applied, and Figure 6 is a single-phase load tap-change transformer of the present invention using a three-legged core. 7 is a winding arrangement diagram of the single-winding transformer shown in FIG. 6, and FIG. 8 is a winding arrangement diagram of the two-winding transformer shown in FIG. 6. . 10... Main transformer part, 20... LVR part,
30...Tap changer on load, 1...Series winding,
2A...Shunt main winding, 3...Tertiary winding, 4...Excitation winding, 23, 24...Shunt partial winding, 51, 5
2,151,152...Tap winding, 61,62
...Polarity switch, 71, 72...Tap selector,
81, 82...Switching switch, 90...Single-phase three-leg iron core, C...Iron core main leg, _S1 , _S2 ...Side leg, 101...
...High voltage main winding, 102...Medium voltage winding, 123,1
24...High voltage partial winding, U, O...High voltage terminal,
u, v... medium voltage terminals, a, b... tertiary terminals.

Claims (1)

[Scope of Claims] 1. A main transformer section in which at least a high-voltage side winding and a low-voltage side winding are wound around an iron core main leg, and an auxiliary iron core leg connected in parallel with the low-voltage side winding of the main transformer section. 2 connected to the excitation winding and the neutral point side of the high voltage side winding
and an on-load voltage regulator part wound with two tap windings, wherein the main transformer part is constructed by winding each of the windings around the main leg of one of the iron cores, and when the load A partial winding that is connected to the neutral point side of the high voltage side winding to form a two-parallel circuit is wound on the auxiliary core leg of the voltage regulator portion, together with the excitation winding and each tap winding, A load tap that connects the neutral point side of each of the partial windings and each of the tap windings in series to form a parallel circuit, and includes two switching switches that use the taps of each of the tap windings in parallel. A load tap switching transformer characterized by switching using a switching device. 2. A patent characterized in that the iron core uses a single-phase three-legged iron core, the main leg of the iron core is used as the main transformer part, and one of the two side legs is used as the auxiliary iron core leg of the on-load voltage regulator part. An on-load tap-changing transformer according to claim 1. 3. The on-load tap switching transformer according to claim 1, wherein the auxiliary core leg of the on-load voltage regulator portion is a separate core from the main core leg of the main transformer portion. 4. Claim 1, 2, or 3, characterized in that a tertiary winding is disposed on the main leg of the iron core of the main transformer portion and connected in parallel with the excitation winding. on-load tap-changing transformer.