JPS5836484B2 - Fukaziden Atsushi Yousei Kitsuki Tansou Hen Atsuki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a large single-phase transformer with an on-load voltage regulator.

Recently, transformers used in ultra-high voltage power transmission systems have become larger.
Mainly due to transportation problems, so-called special three-phase transformers, which are constructed by combining three single-phase transformers, are becoming more common.

On the other hand, when a power transmission system transformer has a built-in low-voltage tertiary winding for the in-house power supply of a substation, for example, the capacity of the low-voltage tertiary circuit breaker must be made small, or the mechanical force in the event of a short circuit must be considered. In order to improve the operation of the power transmission system, there are cases where it is desirable to increase the impedance between the low voltage tertiary winding, the high voltage primary winding, and the medium voltage secondary winding (especially the medium voltage secondary winding). It's becoming more common.

Conventionally, methods for increasing the impedance between the low voltage tertiary winding and other windings of a transformer include significantly increasing the insulation distance between the low voltage tertiary winding and the medium voltage secondary winding. By arranging the Nakasho secondary winding, the high-voltage primary winding, and the low-voltage tertiary winding in this order from the inside on the main leg of the iron core, it is possible to increase the impedance between the windings and increase the short circuit tolerance. It has been done.

However, in the conventional method, the diameters of the high-voltage primary and medium-voltage secondary windings become large, which is uneconomical, and there are transportation problems, or the high-voltage primary windings are at extremely high voltages such as 500 kV. In some cases, because the insulation dimensions between the high-voltage primary and low-voltage tertiary windings become large, the impedance between each winding can be reduced without increasing the insulation distance by connecting the wires as shown in Figure 1. An invention for increasing the number of
No. 887, (Special Publication No. 52-7974).

Next, to explain the outline of the single-phase transformer shown in Fig. 1, in the figure, C0 to C3 are the core main legs, and L is the core main leg C1.
The winding unit of the low voltage tertiary winding, M1, M2, M
3 is the winding unit of the medium voltage secondary winding wound around the iron core main legs 01 to C2, C3, respectively, and H1H2, H3 is the high voltage primary winding unit wound around the iron core main legs C, , C2, C3, respectively. The high voltage primary winding units H1 to H3 and the secondary winding units M1 to M3 are respectively connected in parallel.

U and 0 are high voltage terminals, u and O are medium voltage terminals, and a and b are low voltage terminals.

In this way, n (three in this example) main landing gears C1, C2,
A medium-voltage secondary winding formed by connecting in parallel winding units M1, M2, and M3 that are divided and placed on each core main leg, and a winding unit H1 that is divided and placed on each core main leg. , H2, H3 connected in parallel or in series as appropriate, and the low voltage from the n1 (in this example, 1) winding unit L1 placed at the innermost side of any iron core main leg. By configuring it with a tertiary winding, the impedance between each winding can be dramatically increased.

Now, as a means to adjust the voltage in such a single-phase transformer, a load voltage regulator (hereinafter referred to as LVR) is installed separately or the winding is placed on the same leg as the high-voltage primary winding and the low-voltage secondary winding using a tap. It is possible to install it on the side yoke.

When the tap winding is on the same leg as the high-voltage primary winding and the low-voltage secondary winding, the current flowing in each winding is determined by the transformer capacity and terminal voltage.

However, with today's large-capacity transformers, LVRs may be installed separately, mainly due to transportation issues.

When the LVR is installed separately, the low voltage tertiary winding L1 and the excitation winding S1 are connected as shown in Fig. 2 (C4 is the core main leg of the LVA), and the excitation winding S1 connects the tap windings T1,
When voltage is induced in T2, the current distribution in each winding is affected by the impedance between each winding of the main transformer and LVR, and the current in main transformer windings H2 and M2 varies depending on the tertiary load, It is not easy to determine the current flowing through the

This also poses a problem in terms of improving the reliability of the transformer.

The purpose of this invention is to provide a single-phase transformer with an on-load voltage regulator that can improve the above-mentioned drawbacks, easily determine the current flowing through each winding, and improve the reliability of transformer design. It's about doing.

The key point of this invention is that when the LVR is placed separately in a connection that increases the impedance between the secondary and tertiary as shown in Fig. As a means to eliminate the influence on the distribution, the LVR excitation winding that is connected to the transformer tertiary winding and the main transformer excitation winding that is connected to the tertiary load are provided on separate iron core main legs. .

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

FIG. 3 shows an embodiment of the present invention.

The single-phase transformer of the present invention has a core having two or more main legs (excluding auxiliary legs), such as a five-legged core with three main legs or a four-legged core with two main legs. The one given is used.

FIG. 3 shows one having two core main legs C1 and C2.

Each winding unit M1+H1, M2, H2 of medium voltage secondary winding and high voltage primary winding divided into two is attached to these core main legs.
are arranged sequentially.

Further, inside the medium voltage secondary winding M1, a low voltage tertiary winding L1 is arranged on the iron core main leg C1 side, and an excitation winding S/ is arranged on the iron core main leg 02 side.

Regarding the LVR, each winding unit of the core main leg C4, C5K excitation winding and tap winding is Sl * Tl *S
2 and T2 are arranged sequentially.

Medium voltage winding unit M1. M2 is connected in parallel to medium voltage terminals u, O
K. In addition, the high voltage winding units H1 and H2 are connected to the tap winding T1T2 to form the high voltage winding terminal U. Connect to 0.

The low voltage winding L1 is connected to low voltage winding terminals a and b, and is also connected to an excitation winding S1 which excites the tap winding T.

The excitation winding number is the excitation winding S2 that excites the tap winding T2.
Connect to.

With the above structure, even if the tertiary load fluctuates, the magnetic coupling of the windings wound around other core legs that do not have a tertiary load is separated, so that
The current distribution in the winding is not affected by the excitation winding connected to the tertiary load, which improves reliability in single-phase transformer design.

However, in the structure shown in Fig. 3, the low voltage tertiary winding L1
When the load is removed, the terminal voltage of the low-voltage tertiary winding L1 drops, and the amount of magnetic flux generated by the excitation windings S1 and 82 is different, so this difference in the amount of generated magnetic flux becomes leakage magnetic flux, causing local overheating. There is a risk.

An embodiment that prevents this problem is shown in FIG.

That is, the auxiliary leg C6 is provided on the core main leg on the side of the tap winding T2 from which the load is not taken out.

By doing this, a magnetic flux equal to the difference in the amount of magnetic flux generated by the excitation windings S1 and 82 passes through the auxiliary leg C6, thereby preventing local overheating.

FIG. 5 shows still another embodiment of the present invention, which differs from FIGS. 3 and 4 in that the main transformer is a five-legged iron core transformer with three iron core main legs. It is.

In this case, the excitation winding S for the high voltage primary windings H2 and H3
By connecting 2 as shown in the figure, only one is required, which increases the economical efficiency in manufacturing the transformer.

According to this invention, when a separately installed LVR is attached to a single-phase transformer designed to increase the impedance between the low-voltage tertiary and medium-voltage secondary windings, the current flowing through each winding is equal to the capacity and voltage. This has the effect of making it possible to easily obtain the transformer design, thereby improving the reliability of the transformer design.

[Brief explanation of drawings]

Fig. 1 is a winding arrangement diagram of a single-phase transformer that is the object of this invention, Fig. 2 is a winding arrangement diagram of a single-phase transformer with on-load voltage regulator, which is the premise of this invention, and Figs. FIG. 5 is a winding arrangement diagram showing an embodiment of the present invention. Explanation of symbols C1 to C3... Iron core main landing gear, C4, C
5... LVR main leg, C6... LVR auxiliary leg, H1 to H3... Winding unit of high voltage primary winding, M1 to
M3... Winding unit of medium voltage secondary winding, L1... Winding unit of low voltage tertiary winding, T1, T2... Tap winding, S
1, S2... Excitation winding of tap winding, 82 * S
3... Main transformer excitation winding.

Claims (1)

[Claims] 1 Medium-voltage secondary winding in which winding units are connected in parallel to each core main leg having n (an integer of n≧2) main legs, and winding units are each divided and arranged on each core main leg. high-voltage primary windings connected in parallel or in series, and n-m (1≦m≦n-1
), the excitation winding and the high voltage primary are installed separately from the single phase transformer and are connected in parallel with the low voltage tertiary winding. In a device equipped with a load voltage regulator in which a tap winding connected in series to the neutral point side of the winding is arranged on the main leg of the iron core,
Excitation windings to take the load are arranged on the m core main legs of the single-phase transformer, and the on-load voltage regulator has a plurality of core main legs, and each core main leg has an excitation winding. The excitation winding of one core main leg is connected to the low-voltage tertiary winding of a single-phase transformer, and the excitation winding of the other core main leg is connected to a single core that does not take a tertiary load. A single-phase on-load voltage regulator, characterized in that it is connected to the excitation winding of a phase transformer, and each tap winding is connected in series to the neutral point side of each high-voltage primary winding of the single-phase transformer. transformer.