JPS61204919A - Three winding scott connection transformer - Google Patents

Abstract

PURPOSE:To enable miniaturization and the reduction of a manufacturing price by containing iron cores and windings corresponding to those of two pairs in a tank, by connecting two primary windings in parallel and by connecting to a primary line with three bushings. CONSTITUTION:The primary winding 17 and the secondary winding 16 for a main transformer are wound around the first iron core leg 12, the primary winding 19 and the tertiary winding 18 for the main transformer are wound around the second iron core leg 13, the primary winding 21 and the secondary winding 20 for a teaseat transformer are wound around the third iron core leg 14 and the primary winding 23 and the tertiary winding 22 for the teaseat transformer are wound around the fourth iron core leg 15. The primary windings 17, 21 wound around the first iron core leg 12 and the third iron core leg 14 and the primary windings 19, 23 wound around the second iron core leg 13 and the fourth iron core leg 15 are separately Scott-connected and only the terminals U, V, W to be connected to the lines of two pairs of primary winding groups are connected in parallel. This satisfies leakage impedance characteristics, removes the trouble in operation, can reduce the insulation grade of the secondary and the tertiary windings and the circuits to a half, enables miniaturizaiton and light weight and can reduce the manufacturing price.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a Scotto connection transformer used as a power feeding transformer.

・、[Technical background of the invention and its problems]: High-speed electric vehicle It is constructed of a phase conversion transformer 1 and a step-up transformer 2, and is used as a backup.

(For example, “Railway Technology Research Institute Bulletin J, March 1984, N
o-A-84-39, published by Japan National Railways, P2.3) The primary winding of the three-phase two-phase conversion transformer 1 is Y-connected and receives power at voltage GL, and the secondary winding is If the voltage between one set of output terminals ae of this secondary winding is E2, the voltage between the other set of output terminals b'4' becomes E2ZS, and the voltage between terminals aC and terminals b' and d' is The voltage phase difference is 90 degrees.

Voltage between step-up transformer 2r input terminals h' and d' Ez/
This is an autotransformer that boosts the voltage E9 between the output terminal bd and the output terminal bd.

This modified Woodbridge connected transformer method has the advantage that the primary neutral point 0 is grounded directly, so power can be received directly from the ultra-high voltage line, and the insulation of the primary winding can be significantly reduced.

However, there are cases where the received voltage E1 is not only 154 KV or less, but also from the 6 ultra-high voltage lines of the receiving terminal, and in this case, it is not necessary to draw out the neutral point on the primary side and ground it.

In addition, a step-up transformer 2 is required in addition to the three-phase to two-phase conversion transformer 1, which increases the size and manufacturing cost.
Another drawback is that it requires a large installation space and a large amount of construction cost.

Next (:, Reduction of insulation class on the secondary side C and explanation "t'
Ru.

Figure 9 shows the primary side of a single-phase, two-winding military transformer 3 (-power supply 4
is connected to the secondary side through the circuit breaker 5 and the transformer 6.
The figure shows a conventional autotransformer power system (A, T system). In this system, the secondary side of military transformer 3 ("i Since this is a system, when the autotransformer 6 is not connected, that is, when the disconnector 5 is open, a ground fault may occur on the secondary side. (secondary pressure, which is twice the voltage ET)]
2 (It is set as an insulation class equivalent to Yu.

Figure 10 shows a recently developed new AT system.1.Then, a military transformer 8 is equipped with a secondary % wire and a tertiary winding having electrician voltage ET and ζ2 equal voltage B272. It is a single-phase three-winding wire.

That is, the power source 4 of voltage E1 is connected to the primary winding 9C2, and the secondary winding 10 and the tertiary winding 11 are connected in series (: connected).
The connection point N is grounded, and a single transformer 6 is connected to the terminals T and F at both ends via a breaker 5.

3 is a circuit diagram for feeding power to an electric vehicle 7. FIG.

In actual use, these circuits are divided into two circuits and configured so that the phase difference between their output voltages is 90 degrees f2.
If the loads on both seats are the same, the current from the three-phase power supply on the primary side is increased by 5f to obtain three-phase balance.

In this new AT system, even when the breaker 5 is open, the connection point N is grounded, so the insulation class on the secondary and tertiary sides is the electric vehicle voltage ET-1'', that is, secondary and tertiary. Voltage 1!
A value equivalent to 2 1272 is sufficient, which is half of the conventional method.

However, even if one end is connected at the connection point N, since the secondary winding 10 and the tertiary winding 11 are connected, both windings (-) will cause unbalance in the load current flowing through them. , at the time of a ground fault (
Since there is a risk that an abnormal voltage may be generated in the military transformer 8, it is necessary to properly distribute the leakage impedance between the windings of the military transformer 8 so that the leakage impedance ≦2σ. I will explain it next.

Leakage impedance is measured from the voltage and current when one of the windings 1 and 12 is short-circuited, voltage is applied to the other winding, and the other windings are open. and i leakage impedance Z1゜Z2. ZB is (1)
The formula becomes

This leakage impedance Zll Z2. In relation to za, Z2. It is necessary to set almost the same value f2 to and za, and it is also necessary to reduce the supply value of Zl. In other words, if the value of zl is positive,
If it is thicker, the characteristic of this new AT method is that the degree of current unbalance that flows more due to the force of the secondary winding than that of the tertiary winding increases, and the reverse ≦-Zl (lK is in the negative direction (- If it is too large, if the secondary side is short-circuited, the voltage rise on the tertiary side will be too large, and if the tertiary side is short-circuited, the voltage rise on the secondary side will be large, which is not preferable.

Due to such operational constraints, it is a major factor that the leakage impedance characteristics of the military transformer 8 satisfy the relationship of equation (2).

[Objective of the Invention] Objective 6 of the Invention In view of the points explained above, when the receiving voltage El is 154 KV or less (- to obtain a three-winding Scott-connected transformer that is compact and can reduce manufacturing cost if applied) It is.

[Summary of the Invention] The military transformer of the present invention is constructed by combining two sets of conventionally used Scotto connection transformers (one core and one winding).
The two sets of primary windings are connected in parallel inside the tank, and the three UVW bushings (one
The insulation class of the secondary and tertiary insulation is half of the conventional C2, but it is possible to satisfy the relationship of equation (2) of the leakage impedance characteristic.

[Embodiment of the Invention] The present invention will be described below with reference to an embodiment shown in FIG. The first core leg 12 is wound with a main seat secondary winding 16 and a corresponding main seat primary winding 17 .
"-" is wound with the main seat tertiary winding 18 and the corresponding main seat primary winding 19.The first and second iron core legs 12 and 13
C. The secondary winding 16, the tertiary winding 18, and the primary windings 17 and 19 have the same dimensions and the same number of turns.

The HT discarded secondary winding 20 and the corresponding T continuous primary winding 21 are wound around the third core leg 14, and the fourth core leg 15
A T-buckled tertiary winding 22 and a corresponding primary winding blade for a T-car are wound around the winding. The third and fourth core legs 14 and 15 have the same dimensions, and the secondary winding 20, the tertiary winding 22, and the primary windings 21 and 23H have the same dimensions and the same number of turns.

The secondary winding 16 and the tertiary winding 18 for the main seat are arranged so that a circulating circuit can be formed by winding and cross-connecting the upper and lower parts.

The upper and lower ends of the primary winding 17.19 tl for the main seat are line terminals U.

W and its center is the connection point M1 m Ml.

The secondary winding 20 and tertiary winding 22 for the T-seat are wound in the usual way, and the primary winding 21.23 is divided into upper and lower windings, and the upper and lower ends are the line terminals V, and the middle is connected. Point Ml.

Let it be Ml.

Then, connect the connection points Ml and Ml for the main seat and T seat, respectively.

The voltage generated in the T primary winding 21 and 23 is the main winding 1.
The voltage applied to the secondary winding 17.19 is set to 872 times the applied voltage El, and the secondary winding 16.20 and the tertiary winding 1
8゜221-The magnitude of each generated voltage is F'Ia/
C; so that it becomes 2.

The above configuration (if a 3-phase power supply is applied to the primary side terminals U, V, and W), it functions similarly to an ordinary Scotto connection transformer, and the secondary winding 16 of the main seat The voltage of the same phase is applied to the tertiary winding 18, and the voltage of the same phase is applied to the secondary winding 20 for the T position and the tertiary winding 2.
2, voltages having a phase difference of 90 degrees from the voltage for the main seat are obtained.

and apply the same load to each secondary winding and tertiary winding at the same time.
When connected, the three-phase current σ flowing from the primary side is balanced, similar to an ordinary Scotto connection transformer.

It is clear that the insulation class of the secondary winding and the tertiary winding can be half of the conventional one since one end N of the winding is always grounded during use.

The characteristics will be explained using Figures 2 to 5. These relationships are shown in C1 to make it easier to understand the configuration shown in FIG.

Figures 2 to 5 are circuit diagrams for measuring leakage impedance between the windings of this transformer. The current is indicated by an arrow.

FIG. 2 shows the measurement of the leakage impedance Zat between the secondary winding and the primary winding for the main seat, and current flows through the secondary winding 16 and the primary winding 17.

Next (: When measuring the leakage impedance Z81 between the tertiary winding and the primary winding for the main seat, simply move the tertiary winding 18C-power supply 24 in Figure 2, and the secondary winding 18 and primary winding 191
; Current flows. These two measurements are the same size.

Since this is a combination of windings with the same number of turns, equation (3) is obtained.

Z21 = Zsl−−−−−−−−−−−−−−−
------------
1e Small model 11 Middle model 11 Current flows through all the windings, and the conditions under which Z21 and Z81 were measured were connected in series, which corresponds to C2, and formula (4) is obtained.

Z28 = Z21 + Zst −−−−−−−−
−−−−−−−−−−−−−(4)(3), (4
Substituting the relationship in equation (1) into equation (1), Zn = O, Zi
! It can be seen that the relationship = ze = Z21 is obtained and formula (2) is satisfied.

Figure 4 shows the measurement of the leakage impedance Z'21 between the secondary winding and the primary winding for the T seat, and the leakage impedance Z'21 is measured between the secondary winding 20 and the primary winding 21 and the primary winding for the main seat. Winding 17 and secondary winding 16 (
- Current flows. The current in the primary winding 21 is shunted at the terminal ■, flows through the short circuit lead 25 to the primary winding 17, and connects to the connection point M.
Flowing as if merging at 1. And the primary winding 17i: IU secondary winding jI11 to cancel the generated ampere turn.
6 CH circulating current flows.

The leakage impedance Z'll in FIG. 4 is designed to have the same value as the aforementioned Zll.

Next, when measuring the leakage impedance Z'81 between the tertiary winding for the TT seat and the primary winding, the tertiary winding 221 is
The current flows through the tertiary winding 22, the primary winding 23, and the primary winding 19 and the tertiary winding 181 for the main seat.

Since these two measurements are a combination of windings with the same dimensions and the same number of turns, equation (5) is obtained.

Z'zx = Z'81 −−−−−−−〜−−−
−−−−−−−−−−−−− (5) Figure 5 1-j Leakage impedance Z' between secondary winding and tertiary winding for T seat
2B is being measured, the power source 24 is connected to the secondary winding 20, and the tertiary winding 22 is short-circuited by the short-circuit lead 25. In this case, the windings that pass through t-r are all for the main seat and the T seat, and this corresponds to the condition where the leakage impedances z'21 and Z'31 were measured in series, so ( 6
) formula is obtained.

Z'*s = Z'21 + Z'si ---
−−−−−−−−−−−−−−−−(6)(5),
Substituting the relationship in equation (6) into equation (1) l:, we get Zx:=0
．． The relationship Zii = Z3 = Z'21 is obtained (2)
It can be seen that the formula is satisfied.

The core configuration is general (: core legs 12 and 13, core leg 14
Although this is a two-iron core system in which C and 15 are each integrated, it is also possible to use separate C2 legs for each leg or a system in which four legs are integrated. What is necessary is to adopt the method that is most suitable for transportation to the installation site, conditions of the installation site, etc.

Although it is impossible to achieve 9 stages of reduced insulation on the primary side by grounding the neutral point on the primary side, it is impossible to achieve 9 stages of insulation on the primary side by grounding the neutral point on the primary side. Even if you don't draw out the points, it doesn't pose much of a problem from the perspective of reducing insulation.

As can be seen from the above description, the present invention (-) satisfies the leakage impedance characteristics and has the following features.

(1) One tank system allows for compact size and quantity.

(2) The secondary and tertiary insulation classes can be halved compared to conventional ones. And second and third order circuits 1- are used. Similarly, circuit breakers, disconnectors, lightning arresters, etc. can also be used as devices with low insulation class.

(3) Sand inch winding method in which the primary winding with high voltage is placed on the outside, making it easy to tap out the primary winding, which is advantageous in terms of insulation structure, and placing the primary winding on the inside. Therefore, the dimensions can be reduced.

(4) There are few types of windings of the core legs 12 and 13 and of each of the core legs 14 and 15, making the work easy.

FIG. 6 shows a modified example of the main seat winding, in which the primary winding 26 is cross-connected, and the current flowing from the T seat primary winding is connected as shown by the arrow f2. The primary winding 26 has the advantage of not generating a complicated (secondary winding 16 and tertiary winding) 8C circulating current.

Next, how the load is applied to the secondary side and the tertiary side: In some cases, a larger load is applied to the secondary side than the tertiary side. For example, a load of 1n130% on the secondary side and a load of 0% on the tertiary side (near 0%) may be applied for a short time.

In the case of the connection shown in the diagram m1, when a 130-chi current flows through the secondary windings 16 and 21J, a 130-chi current flows through the primary winding]7. When a 70% current flows through the tertiary windings 18 and 22+', a 70% current flows through the primary winding 19C2.

It is necessary for the transformer to withstand such load imbalance.

The means for achieving this objective are shown in Figure 7).

In FIG. 7, the connection shown in FIG.
Since 70% current flows through the tertiary winding 22, the current is 1.
Approximately 118% current flows through the next winding 171U. When 70% current flows through the tertiary winding 181 and 130% current flows through the secondary winding 20, approximately 89% current flows through the primary winding 19 (Y).

In other words, in FIG. 1, a large current flows through the primary winding 17 (1
Since a small current flows through each of the secondary windings 19, the temperature of the primary winding 17 increases. On the other hand, in FIG. 7, the current in the primary winding 17 becomes large, but it does not become 1, and the current in the primary winding 19C is less than 100%. The temperature will be lower than in FIG.

In this way, when an unbalanced load is applied to this Scott-connected transformer, the temperature rise in the primary winding 17 is reduced, and the deterioration of the insulator due to the high temperature can be reduced. Conversely, since the temperature does not increase, thinner wires can be used, and material costs can be reduced.

It goes without saying that the configuration of the two C windings can be modified and implemented as appropriate without changing the gist thereof.

In addition, if the capacity is large or the transportation conditions are small and transportation is difficult, a method is adopted in which the main transformer and T-seat transformer are stored in separate tanks and connected with an oil submerged duct. You may.

[Effects of the Invention] As described above (according to the present invention), the primary winding and the secondary winding for the main transformer are wound around the first core leg C; and the tertiary winding are wound around the second core leg, and the primary and secondary windings for the T-seat transformer are wound around the third core leg. In the case where the tertiary winding is wound around the fourth core leg (-, the primary winding is wound around the first core leg and the third core leg, and the second core leg and the fourth core leg (-) are wound. The primary windings are connected separately (the two sets are connected separately, and one of the two sets is
Only the terminals that are connected to the line of the next winding group are connected in parallel (rather than connecting with U), which satisfies the leakage impedance characteristics, eliminates operational problems, and insulates the secondary and tertiary windings and circuits. It is possible to provide a three-winding Scotto connection transformer that can reduce the number of classes by half, can be made smaller and lighter, and can reduce manufacturing costs.

[Brief Description of the Drawings] Fig. 1 is a wiring diagram showing an embodiment of a three-winding Scott-connected transformer according to the present invention, and Figs. 2 to 5 show the connection of the windings and each winding according to A wiring diagram showing measurement of leakage impedance between lines, FIG. 6 is a wiring diagram showing a part of another embodiment according to the first aspect of the present invention, FIG. 7 is a wiring diagram showing a dependent invention of the present invention, and FIG. 8 is a wiring diagram of a feeder transformer with a conventional modified Woodbridge connection, and Figure 9 shows a conventional modified Woodbridge connection 4:
Figure 10 is an explanatory diagram of the circuit configuration of the AT system in the new three-winding feeder phase transformer (Yu). 1. Three-phase two-phase conversion transformer 2.・Step-up transformer 3.8...Feeding phase transformer 5
... Breaker 6 ... Autotransformer 7 ... Electric car 12.13.14.15 - ... Iron core leg 9
, 1? , 19.21.23...Primary winding 10, 16
．． 20...Secondary winding 11, 18.22...Third winding 11, 18.22...Third winding 1. Figure 8

Claims (2)

[Claims] (1) The primary and secondary windings for the main transformer are wound around the first core leg, and the primary and tertiary windings for the main transformer are wound around the second core leg.
The primary and secondary windings for the T-seat transformer are wound on the third core leg, and the primary and tertiary windings of the T-seat transformer are wound on the fourth core leg. In the case where the core legs are wound, the primary windings wound around the first core leg and the third core leg, and the primary windings wound around the second core leg and the fourth core leg are separated. A three-winding Scott-connected transformer characterized in that the three-winding Scott-connected transformer is characterized in that only the terminals connected to the lines of the two primary winding groups are connected in parallel. (2) The primary and secondary windings for the main transformer are wound around the first core leg, and the primary and tertiary windings for the main transformer are wound around the second core leg.
The primary and tertiary windings for the T-seat transformer are wound on the third core leg, and the primary and secondary windings of the T-seat transformer are wound on the fourth core leg. In the case where the core legs are wound, the primary windings wound around the first core leg and the third core leg, and the primary windings wound around the second core leg and the fourth core leg are separated. A three-winding Scott-connected transformer characterized in that the three-winding Scott-connected transformer is characterized in that only the terminals connected to the lines of the two primary winding groups are connected in parallel.