WO2019198843A1

WO2019198843A1 - Three-phase power compound transformer with harmonic active filter function using three-phase power autotransformer

Info

Publication number: WO2019198843A1
Application number: PCT/KR2018/004280
Authority: WO
Inventors: 김기성; 김대한
Original assignee: 김기성; 김대한
Priority date: 2018-04-12
Filing date: 2018-04-12
Publication date: 2019-10-17
Also published as: KR101931218B1

Abstract

The objective of the present invention is to provide a three-phase active harmonic filter that is useful not only in emergencies but also in normal times since the three-phase active harmonic filter can be used in emergencies as an open phase recovery device that prevents accidents in which one phase is lost, can be used as an autotransformer that outputs three-phase 380 V and three-phase 220 V, and at the same time can be used as an active harmonic filter. A transformer according to an aspect of the present invention, for achieving said objective, comprises a plurality of zigzag connection units (130) connected to a power supply system (100) having a three-phase connection for supplying an alternating current power to a load (110), wherein the plurality of zigzag connection units (130) have a single winding core having three legs (131, 132, 133). On the legs, zigzag wires (R1, Rn; S1, Sn; T1, Tn) of a three-phase transformer and wires (R2, Rn*; S2, Sn*; T2, Tn*) symmetric to the zigzag wires of the three-phase transformer are wound. The end (Rz) of wire R2 and the beginning (Sa) of S1 of the three-phase transformer are connected to the S phase; the end (Sz) of S2 and the beginning (Ta) of T1 are connected to the T phase; the end (Tz) of T2 and the beginning (Ra) of R1 are connected to the R phase; and three Ns which are the beginnings of Rn, Sn, and Tn, and three Ns which are the ends of Rn*, Sn*, and Tn* are all connected to the N phase.

Description

Three-phase power lottery transformer with harmonic active filter function using three-phase power single winding transformer

The present invention relates to a three-phase electric transformer, and more particularly, to a power transformer capable of attenuating harmonics to improve power quality and to minimize size even at large currents.

That is, the present invention has an active harmonic filter function that is installed in parallel with the power stage when the harmonics occur in the load side to absorb the harmonics. It is a transformer that outputs both three-phase 380V and three-phase 220V on the load side.It is used as a single winding transformer that outputs three-phase 380V and three-phase 220V, and improves power quality by attenuating harmonics with an active harmonic filter. It is very useful.

Since electricity is invented and using alternating current, humans cannot use it without transformers. In other words, since the supply system is efficiently supplied at high pressure in the distribution system, the higher the power transmission and the closer to the consumer, the more stable the transformation to the low pressure is necessary. Therefore, the transformer cannot be transmitted from electricity including power transmission.

Moreover, since the history of using a three-phase power supply for a variety of reasons, including the problem of balance in transmission of ultra-high voltage, the harmonic power problem has emerged in the 21st century.

Harmonics are devices that use a stationary frequency, returning some of them to the power line instead of using all of their power, causing them to go around with power waste and cause various problems.

The problem is that the frequency is increased and the capacitor is oversaturated and destroyed, the overcapacity of the neutral wire is increased, the speed of the motor is uneven, the noise of various control equipment, etc.

Conventional harmonic filters include passive filters, active filters, and image harmonic filters. In the passive filter, a specific frequency and a specific current are set and the specific frequency and the specific current are attenuated. However, if it is less than the specific frequency and the specific current, the attenuation is not good. If more than the specific current, it will overheat and burn out.

The active filter has a problem that harmonics are generated when the electronic equipment is wrong as the electronic equipment is canceled by generating a reverse frequency of a specific frequency with the electronic equipment, and the price is considerably high.

The video harmonic filter has a zigzag connection structure in which the active filter and a part of the video harmonic are attenuated (about 50%).

On the other hand, as a first conventional technology relating to harmonic filters and transformers, techniques such as Korean Patent Publication No. 2014-0032300 (Harmonic Reduction Hybrid Transformer) are disclosed.

This, as shown in Figure 1, the first conventional technology provides a transformer capable of suppressing harmonics of 5th harmonic and other orders based on the 3rd harmonic, overheating of the neutral wire by the harmonics and overheating of the transformer enclosure The present invention relates to a harmonic rejection hybrid transformer that improves power quality such as rejection, increases power efficiency by reducing power loss due to harmonic currents, and guarantees device life.

The first conventional technology includes a secondary, tertiary low voltage winding (zigzag winding) made of a winding having a phase of 180 degrees with respect to the harmonic order generated in the load, based on the primary high voltage winding (delta winding) of the transformer. It is characterized by.

However, in the case of the first prior art, many windings such as primary, secondary, and tertiary are required, and strictly speaking, if considering up to a separate primary side winding, all four lotteries having four primary windings are considered. It becomes a type transformer, which increases in size and is extremely inefficient.

On the other hand, as a second prior art relating to harmonic filters and transformers, techniques such as Korean Patent No. 1828831 of the present inventors (power transformers with improved harmonic attenuation and large current phase recovery functions) are disclosed.

The second conventional technology can be used as an imaging repair device that prevents accidents in which phases are lost in emergencies, and can be minimized in large currents by dispersing phase currents, and attenuates image harmonics as well as 5 and 7 harmonics to further improve power quality. It is to provide a three-phase electrical transformer to improve.

The second prior art transformer, as shown in Figures 2 and 3, the delta-zigzag connection unit 120 connected to the power supply system 100 having a three-phase connection for supplying AC power to the load 110, As a transformer having, the delta-zigzag connection section 120 has a single winding core having three

legs

121, 122, and 123, and windings of three-phase transformers R1, R2; S1, S2; T1, T2 for each leg. And winding for winding phase recovery (Rn; Sn; Tn), and windings (R1, R2; S1, S2; T1, T2) of the three-phase transformer are connected to each other in a leg of each phase. A tap at a third point of the wound winding of the transformer is connected to one end of the phase-recovery winding of the neighboring phase, and the other end of each phase-recovery winding is connected to a neutral point, and each of the phase-recovery windings Rn and Sn Each turn of Tn is 1/3 of the corresponding ones of the windings R1, R2; S1, S2; T1, T2 of the three-phase transformer.

However, in the case of the delta-zigzag method of the second prior art, there is a limit that the efficiency of the delta winding is not very high in the plurality of phases, although it has harmonic attenuation and phase recovery functions.

The object of the present invention is to solve the common problems of the prior art described above, the first object of the present invention is to remove the harmonics (active filter) while being installed in parallel to the power line, three-phase 380V and three-phase 220V single winding transformer The present invention provides a three-phase electric transformer that is useful for everyday use.

It is a second object of the present invention to provide a three-phase electric transformer capable of minimizing size even in large currents by dispersing phase currents.

It is a third object of the present invention to provide a three-phase electric transformer that further improves power quality by attenuating 5 and 7 harmonics as well as image harmonics.

It is a fourth object of the present invention to provide a three-phase electric transformer that has excellent phase recovery function and can also be used as a power factor correction device.

A fifth object of the present invention is to provide a three-phase electric transformer capable of improving the phase unbalance ratio.

Transformer according to an aspect of the present invention for achieving this object, a transformer having a plurality of zigzag connection unit 130 connected to the power supply system 100 having a three-phase connection for supplying alternating power to the load 110 The plurality of zigzag connection units 130 may include a single winding core having three

legs

131, 132, 133, and each of the zigzag windings R1, Rn; S1, Sn; T1, Tn) and the zigzag symmetrical windings (R2, Rn *; S2, Sn *; T2, Tn *) of the three-phase transformer are wound and windings R2 end (Rz), S1 start (Sa) of the three-phase transformer ) Is connected to S phase; S2 end Sz and T1 start Ta are connected to T phase; The T2 end Tz and the R1 start Ra are connected to R phase; Six Ns are connected to N on all three Ns that are the beginnings of Rn, Sn, Tn, and three Ns that are the ends of Rn *, Sn *, Tn *

There is; The R1 end 2 and the Tn end 7 are connected; The S1 end 5 and the Rn end 1 are connected; The T1 end 8 and the Sn end 4 are connected; R2 start (3), Sn * start (4 *) are connected; S2 start (6), Tn * start (7 *) are connected; T2 start (9), Rn * start (1 *) is characterized in that is connected.

Preferably, the first and second, third and fourth R-phase windings Rn *, Rn, R1, and R2 are wound on the R-phase legs 131, and the first and second are wound on the S-phase legs 132. The second, third, and fourth S-phase windings Sn *, Sn, S1, and S2 are wound, and the T-phase legs 133 have the first, second, third, and fourth T-phase windings Tn *, Tn. , T1, T2) are wound and are all characterized by the same thickness and the same number of turns.

More preferably, the circuit breaker 112 is inserted between the wires of each phase of the power supply system 100 and corresponding windings of the transformer of the plurality of zigzag connection units 130.

Also preferably, a low voltage power may be output from the tap of each of the transformer windings.

According to the present invention having a solution to the above-mentioned problems, it is possible to use as a single winding transformer that outputs three-phase high voltage and three-phase low voltage, and at the same time, further improve power quality by attenuating image harmonics and fifth-order seventh harmonics. It has the added advantage that it can be used as a power factor correction device with excellent phase recovery function. It is possible to improve the equilibrium rate.

1 is a circuit diagram of a harmonic reduction device of the first prior art;

2 is a circuit diagram of a transformer having a phase recovery function of a second prior art;

3 is a vector diagram of a delta-zigzag connection part of a transformer having an imaging recovery function of a second prior art;

4 is a circuit diagram of a three-phase power lottery transformer having a harmonic active filter function using a three-phase power single winding transformer according to a first embodiment of the present invention;

5 is a vector diagram of a plurality of zigzag connection portions of a three-phase power lottery transformer according to a first embodiment of the present invention;

6 is a circuit diagram of a plurality of zigzag connection units of a three-phase power delta lottery transformer using a three-phase power single winding transformer according to a second embodiment of the present invention;

7 is a vector diagram of a plurality of zigzag connection portions of a three-phase power delta lottery transformer according to a second embodiment of the present invention;

8 is a circuit diagram of a plurality of zig-zag connection units of a three-phase power star lottery transformer according to a third embodiment of the present invention;

9 is a vector diagram of a plurality of zigzag connection portions of a three-phase power star lottery transformer according to a third embodiment of the present invention;

10 is a perspective photograph of a three-phase power lottery transformer of the present invention;

11 is a front photograph of a three-phase power lottery transformer of the present invention,

12 is a back photograph of the three-phase power lottery transformer of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 4 to 12 of the accompanying drawings.

Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly interpret the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the embodiments described in the present specification and the configuration shown in the drawings are only the most preferred embodiments of the present invention, and do not represent all of the technical idea of the present invention, and various equivalents that may be substituted for them at the time of the present application and It should be understood that there may be variations.

4 is a circuit diagram of a three-phase power lottery transformer having a harmonic active filter function using a three-phase power single winding transformer according to a first embodiment of the present invention, and FIG. 5 is a three-phase power lottery ticket according to the first embodiment of the present invention. 6 is a vector diagram of a plurality of zigzag connection units of a transformer, and FIG. 6 is a circuit diagram of a plurality of zigzag connection units of a three-phase power delta lottery transformer using a three-phase power single winding transformer according to a second embodiment of the present invention, and FIG. A vector diagram of a plurality of zig-zag connection units of a three-phase power delta lottery transformer according to a second embodiment of FIG. 8 is a circuit diagram of a plurality of zigzag connection units of a three-phase power star lottery transformer according to a third embodiment of the present invention. 9 is a vector diagram of a plurality of zigzag connection portions of a three-phase power star lottery transformer according to a third embodiment of the present invention.

10 is a perspective photograph of the three-phase power lottery transformer of the present invention, FIG. 11 is a front photograph of the three-phase power lottery transformer of the present invention, and FIG. 12 is a rear photograph of the three-phase power lottery transformer of the present invention.

(First embodiment)

Hereinafter, the configuration and operation of the first embodiment of the present invention will be described with reference to FIGS. 4 and 5.

The circuit diagram of the electric transformer in the first embodiment of the present invention, as shown in Figure 4, the power supply system 100 having a three-phase four-wire connection for supplying AC power to the load 110 and the power stage It has a phase recovery function to prevent the power failure caused by phase loss of phase and consists of a transformer for outputting three-phase 380V and three-phase 220V at the load side, the transformer is a plurality of zigzag connection section 130 corresponding to the main body of the transformer And a three-phase four-wire circuit breaker 112.

At this time, the power supply system 100 has three phases (R phase, S phase, T phase) and the N phase of the wire of which the voltage of the neutral point is 0V. For example, the R phase is a wire whose phase of voltage is 0 degrees, S The phase may be defined as a wire having a phase of voltage of 120 degrees, and the phase T may be a wire having a phase of voltage of 240 degrees, but is not necessarily limited thereto and may be changed in phase. However, for convenience of description, the present embodiment will be described with the example. .

First, a plurality of zigzag connection portions 130 will be described with reference to FIGS. 4 and 5, and have a single winding

core having legs

131, 132, and 133, and a winding of a general three-phase transformer is wound around each leg.

That is, the second and third R-phase windings Rn and R1 are wound around the R-phase legs 131, and the second and third S-phase windings Sn and S1 are wound around the R-phase legs 131. The T-phase legs 133 are wound with the second and third T-phase windings Tn and T1, which form a normal normal zigzag connection portion. That is, the end point 2 of the third winding R1 of the R phase of the R phase leg 131 is connected to the end point 7 of the second winding Tn of the T phase of the T phase leg 133 and is connected to the S phase leg. An end point 5 of the third winding S1 of the S phase of 132 is connected to an end point 1 of the second winding Rn of the R phase of the R phase leg 131, and T of the T phase leg 133 is connected. The end point 8 of the third winding T1 of the phase is connected to the end point 4 of the second winding Sn of the S phase of the S phase leg 132.

Further, the first and fourth R-phase windings Rn * and R2 are wound around the R-phase leg 131, and the first and fourth S-phase windings Sn * and S2 are wound around the R-phase leg 131. The first and fourth T-phase windings Tn * and T2 are wound on the T-phase leg 133, and these form an inverse zigzag connection portion opposite to the normal zigzag connection portion. That is, the starting point 3 of the fourth winding R2 of the R phase of the R phase leg 131 is connected to the starting point 4 * of the first winding Sn * of the S phase of the S phase leg 132, and S The starting point 6 of the fourth winding S2 of the S phase of the upper leg 132 is connected to the starting point 7 * of the first winding Tn * of the T phase of the T phase leg 133, and the T phase leg ( The starting point 9 of the fourth winding T2 on the T phase of 133 is connected to the starting point 1 * of the first winding Rn * on the R phase of the R phase leg 131.

In addition, the winding T2 end (Tz), R1 start (Ra) of the three-phase transformer is connected to R phase; R2 end Rz, S1 start Sa are connected to S phase; S2 end (Sz), T1 start (Ta) is connected to the T phase is a form of a general delta connection.

In particular, in the present invention, all three N's of Rn, Sn, Tn, and three Ns of Rn *, Sn *, and Tn * are all connected to N phases.

In addition, the first and second, third and fourth R-phase windings (Rn *, Rn, R1, R2) are wound around the R-phase legs 131, and the first and second phases are wound on the S-phase legs 132, respectively. The second, third, and fourth S-phase windings Sn *, Sn, S1, and S2 are wound, and the T-phase legs 133 have the first, second, third, and fourth T-phase windings Tn *. , Tn, T1, T2) are wound, and are characterized by the same number of windings with the same thickness.

All of the same thickness means the manufacturing is convenient. When you select a wire, you can keep it the same. And it means that all of them are symmetric about N phase.

This is shown in a vector diagram as shown in FIG. 5, and for reference, in the vector diagram of FIG. 5, a parallel vector is wound around the same leg, and the connection relationship between the start point and the end point of each winding and the middle tap is easily understood. Is shown.

In more detail, the first and second, third and fourth R-phase windings Rn *, Rn, R1, and R2 are wound on the R-phase legs 131, and the number of windings is the same.

The number of turns wound by the start (1 *) of Rn * and wound to the end (N) on the iron core of the R-phase leg 131 constituting the first core, and the number of turns wound by the start (N) of the Rn and wound to the end (1). This means that the number of turns wound by the start (Ra) and the end (2) and the number of turns wound by the start (3) and the end (Rz) of R2 are the same, and the area of the turn and the iron core are inversely proportional.

In other words, the area of the core multiplied by the number of turns should be constant. The number of turns here is theoretically the number of turns corresponding to 126.7V, which is 1/3 of the line voltage of 380V, but it was 103.5 turns in the actual experiment. 156 sheets of 0.5mm thick non-oriented iron core were used, so the cross-sectional area was (79.mm (= 158 sheets) x 46.mm). At this time, when making a transformer (156 sheets of non-directional iron core with a thickness of 0.5mm) x (79.mm (= 158 sheets) x 46. mm), the no-load hand and the copper hand should be consistent.

Similarly, the first, second, third, and fourth S-phase windings Sn *, Sn, S1, and S2 are wound around the S-phase legs 132 constituting the second core, and the number wound therein is the same.

The number of turns wound by the start (4 *) of Sn * on the iron core of the S-phase leg 132 and wound to the end (N) is the beginning of Sn (N), and the number of turns wound to the end (4) and by the start of S1 (Sa) It means that the turn turns to the end (5) and the turn turns to the end (Sz) after the start (6) of S2 are the same.

Similarly, the first, second, third, and fourth T-phase windings Tn *, Tn, T1, and T2 are wound around the T phase legs 133 constituting the third core, and the number of windings is the same. .

The number of turns wound by the start (7 *) of Tn * on the iron core of the T-phase leg 133 to the end (N) and the number of turns wound by the start (N) of Tn and the beginning (Ta) by winding This means that the number of turns wound up to the end (8) and the number of turns wound up to the end (Tz) after the start of T2 (9) are the same.

What is unique about the present invention is that all three Ns which are the beginnings of Rn, Sn, Tn, and three Ns which are the ends of Rn *, Sn *, and Tn * have 6 Ns connected to N phases. Winding R2 end Rz of the phase transformer, S1 start Sa are connected to S phase; The connection between S2 end (Sz) and T1 start (Ta) is in the form of a general delta connection}.

More specifically, one of R phase, S phase, T phase, and N phase is disconnected and the voltage and current of one disconnected phase are disconnected to the previous state by the principle of the transformer even when no external voltage and current are given. You can lottery.

The function of the phase recovery winding will be described with reference to FIG. 5. As an example, it is assumed that the T phase is missing (R phase, S phase, and N phase are normal).

The law of the transformer is, as shown in Equation 1, the number of turns (Ni) and the voltage (Vi)

electric current(

There is a rule.

[Equation 1]

Here, if the T phase is missing, the potential and current of (Ta.Sz) will be unknown. However, the potential difference between (Ra.Tz) and (Sa.Rz) is fixed and is, for example, an external power supply voltage of 380V. Since the N phase points to zero potential, the potential difference between the Tn winding point (2.7) and the N phase terminal is 126.7V as the voltage of the vector. The potential difference between the Sn * winding point (3.4 *) and the N-phase terminal is 126.7V as the voltage of the vector.

However, the first, second, third, and fourth T-phase windings (Tn *, Tn, T1, T2) are wound on the third core T-phase leg 133, and are all wound with the same thickness.

If N (Tn *) = N (Tn) = N (T1) = N (T2), then V (Tn *) = V (Tn) = V (T1) = V (T2).

In addition, the first and second, third and fourth S-phase windings (Sn *, Sn, S1, and S2) are wound on the second core S-phase legs 132, and all of them are of the same thickness. If N (Sn *) = N (Sn) = N (S1) = N (S2), then V (Sn *) = V (Sn) = V (S1) = V (S2).

As a result, the potential of (Ta.Sz) is 220V (240 * j *), phase (Ta.Sz) S phase (Ra.Tz) potential difference = 380V, T phase (Ta.Sz) R phase (Sa.Rz) The potential difference is 380V.

By the way, there is a peculiar point that the potential difference between the Tn winding point (2.7) and the N-phase terminal is 126.7V as the voltage of the vector, and the potential difference between the Sn * winding point (3.4 *) and the N-phase terminal is 126.7V as the voltage of the vector. Done.

This is because a typical zigzag has only one potential difference between the Tn winding point (2.7) and the N-phase terminal is 126.7 V as the voltage of the vector. The transformer law ideal for phase recovery is not perfect. In other words, there is a loss. However, because multiple zigzag connections are two, the transformer law is almost ideal for phase recovery. That is, the loss is small, which is a distinguishing feature from the prior art of the present invention.

This has a significant effect on the attenuation due to cooperative neighbors when harmonic voltages occur.

(2nd Example)

Hereinafter, the configuration and operation of the second embodiment of the present invention will be described with reference to FIGS. 6 and 7.

FIG. 6 is a circuit diagram of a plurality of zigzag connection units 130 ′ of a three-phase power delta lottery transformer using a three-phase power single winding transformer according to a second embodiment of the present invention, and FIG. 7 is a second embodiment of the present invention. This is a vector diagram of a plurality of zig-zag connections of a three-phase power delta lottery transformer.

That is, the plurality of zigzag connection portions 130 'of the three-phase power delta lottery transformer in the second embodiment is that the primary delta connection portion is added to the plurality of zigzag connection portions 130 of the first embodiment.

Therefore, a lottery-type transformer having a delta-plural zigzag connection is possible, and the addition of the delta connection part also brings the advantages of the delta connection part.

(Third Embodiment)

Hereinafter, the configuration and operation of the third embodiment of the present invention will be described with reference to FIGS. 6 and 7.

FIG. 8 is a circuit diagram of a plurality of zig-zag connection units 130 ″ of a three-phase power star lottery transformer according to a third embodiment of the present invention, and FIG. 9 is a three-phase power star lottery transformer according to a third embodiment of the present invention. Is a vector diagram of a plurality of zigzag connection parts.

That is, the plurality of zigzag connection portions 130 ″ of the three-phase power delta lottery transformer in the third embodiment is that the primary star connection portion is added to the plurality of zigzag connection portions 130 of the first embodiment.

Therefore, a lottery-type transformer having a star-plural zigzag connection portion is possible, and by adding the star connection portion, the star connection portion also has advantages.

Finally, in the case of a transformer having a zigzag connection in general, the phase recovery function is not sufficiently exhibited as the capacity increases, and in the case of a transformer having a multi-zigzag connection of the first prior art, it is too inefficient because there are many unnecessary connections that overlap too much. In the case of a transformer having a delta-zigzag connection of the second prior art, there is a limit of 10V lower than the rated voltage of 220V when the phase of one phase is applied when a load of 1 kW is applied, but as shown in FIGS. 10 to 12. According to the three-phase power lottery transformer having a plurality of zigzag connection parts, it is found that even a very simple configuration can reduce phase loss by only about 7V, resulting in about 30% increase in phase recovery efficiency. .

As mentioned above, although the present invention has been described with reference to optimal embodiments, various modifications are possible, and the embodiments of the present invention described above should not be construed as limiting the technical idea of the present invention. The scope of protection of the present invention is limited only by the matters described in the claims, and those skilled in the art can change and change the technical idea of the present invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention, as will be apparent to those skilled in the art.

Claims

A transformer having a plurality of zigzag connection parts 130 connected to a power supply system 100 having a three-phase connection for supplying AC power to a load 110,

The plurality of zig-zag connection portions 130 have cores having three legs 131, 132, and 133, and windings of three-phase transformers R1, R2; S1, S2; T1, T2 and windings for phase recovery for each leg. (Rn *, Rn; Sn *, Sn; Tn *, Tn) is wound, the windings R1, R2; S1, S2; T1, T2 of the three-phase transformer are connected to a delta type wiring structure, A transformer characterized in that it is connected to one end of an image-forming recovery winding adjacent to one end of a transformer winding wound on a leg of each phase, and the other end of each image-forming recovery winding is connected to a neutral point.
The method of claim 1,

The first, second, third, and fourth windings Rn *, Rn, R1, and R2 are wound on the R phase leg 131, and the first, second, third, and third windings are wound on the S phase leg 132. The fourth winding (Sn *, Sn, S1, S2) is wound, and the first, second, third, and fourth windings (Tn *, Tn, T1, T2) are wound around the T phase leg 133. And

The T2 end Tz and the R1 start Ra are connected to R phase; R2 end Rz, S1 start Sa are connected to S phase; S2 end (Sz), T1 start (Ta) is connected to the T phase is a form of a general delta connection,

For each leg, the zigzag windings (R1, Rn; S1, Sn; T1, Tn) of the three-phase transformer and the symmetric windings (R2, Rn *; S2, Sn *; T2, Tn *) of the zigzag of the three-phase transformer Wound; Six N's are connected to N on three N's, which are the beginnings of Rn, Sn, Tn, and three N's, which are the ends of Rn *, Sn *, and Tn *;

The R1 end 2 and the Tn end 7 are connected; The S1 end 5 and the Rn end 1 are connected; The T1 end 8 and the Sn end 4 are connected; R2 start (3), Sn * start (4 *) are connected; S2 start (6), Tn * start (7 *) are connected; T2 start (9), Rn * start (1 *) characterized in that the transformer is connected.
The method of claim 1

The R-phase legs 131 are wound with the first, second, third, and fourth R-phase windings Rn *, Rn, R1, and R2, and the S-phase legs 132 are first, second, and third. The third and fourth S-phase windings Sn *, Sn, S1, and S2 are wound, and the first, second, third, and fourth T-phase windings Tn *, Tn, and T1 are wound on the T-phase legs 133. , T2) is wound, the transformer, characterized in that all of the same thickness and the number of turns.
The method of claim 1,

Each of the legs is a transformer, characterized in that the other winding of the other winding is further wound in the form of Δ or Y.
The method according to any one of claims 1 to 4,

Breaker (112), characterized in that the transformer is inserted between the wires of each phase of the power system (100) and the corresponding winding of the transformer of the plurality of zigzag connection unit (130).
The method according to any one of claims 1 to 4,

And a low voltage power can be output from the tap of each of the transformer windings.