JP2021082795A - Tap-equipped transformer - Google Patents

Abstract

To provide a tap-equipped transformer that can deal with by a smaller number of tap positions than P×S contained in a tap provided on the primary side for P voltages (P is an integer of 3 or more) on the primary side and S voltages (S is an integer of 2 or more) on the secondary side.SOLUTION: A tap-equipped transformer (40) includes intermediate taps (41c and 41d, 42c and 42d, 43c and 43d) including a plurality of taps in the middle of primary windings (411, 421, 431), and a tap voltage on the primary side can be switched. The plurality of taps include J tap positions (t1 to t9) (J is an integer of 5 or more), and from among the J tap positions, specific continuous P tap positions (t1 to t5) (P is an integer of 3 or more, and J-2 or less) are associated with each other for switching P tap voltages on the primary side, and the continuous P tap positions corresponding to the switching of the tap voltage are changed, and therefore, the tap voltage on the secondary side can be switched equivalently.SELECTED DRAWING: Figure 7

Description

The present invention relates to a transformer with a tap that switches the voltage on the primary side and the voltage on the secondary side by switching the tap on the primary side.

Conventionally, when it is necessary to handle a plurality of voltages on the primary side or the secondary side of a transformer, a tap is provided on the high voltage primary side or the low voltage primary side. For example, Patent Document 1 describes that a tap other than the rated tap is provided on the low pressure winding. However, when the tap is provided on the secondary side of the low voltage, it is necessary to pull out the tap from the winding thicker than the primary side of the high voltage, and the scale is structurally large. Therefore, the tap is generally provided on the primary side. Often done. Usually, the tap on the primary side is provided on the tap winding interposed in the middle of the main winding, as described in Patent Document 2.

For example, if a transformer with specifications that support the rated voltage on the high-voltage primary side needs to handle multiple voltages including the rated voltage on the low-voltage secondary side, the primary side does not have a tap. Provide a tap on the side. With this configuration, the voltage on the secondary side can be switched equivalently by switching the tap position on the primary side while the rated voltage is applied to the primary side.

On the other hand, if a transformer with specifications that support multiple voltages on the high-voltage primary side needs to support multiple voltages including the rated voltage on the secondary side of constant voltage, it can handle multiple voltages on the primary side. A tap is provided for this purpose, and no tap is provided on the secondary side. Apparently, this configuration is the same as the above case, and by switching the tap on the primary side to a tap other than the rated voltage while applying the rated voltage to the primary side, for example, the design voltage and rating of the switched tap The voltage on the secondary side can be changed according to the ratio with the voltage.

Here, when devising a transformer having specifications corresponding to a plurality of voltages on each of the high-voltage primary side and the low-voltage secondary side, a tap for supporting a plurality of voltages is provided on the primary side, and a tap is provided on the secondary side. It is also conceivable to provide taps to handle multiple voltages.

Japanese Unexamined Patent Publication No. 3-6805 Japanese Unexamined Patent Publication No. 54-18026

However, when M taps (M is usually an integer of 3 or more) are provided on the primary side and N taps (N is usually an integer of 2 or more) are provided on the secondary side, a plurality of voltages on the primary side and two taps are provided. The number of combinations of tap positions for corresponding to a plurality of voltages on the next side is M × N, which is complicated. Moreover, it is not possible to eliminate the switching of taps on the secondary side where the current is larger than that on the primary side.

The present invention has been made in view of such circumstances, and an object of the present invention is a voltage of P ways (P is an integer of 3 or more) on the primary side and an S way (S is 2 or more) of the secondary side. It is an object of the present invention to provide a transformer with a tap capable of responding to a voltage of (integer) by a number of tap positions smaller than P × S included in the tap provided on the primary side.

The tapped transformer according to one aspect of the present invention is a tapped transformer having a plurality of taps in the middle of the primary winding and the tap voltage on the primary side can be switched, and the plurality of taps are J pieces. (J is an integer of 5 or more) is included, and among the J tap positions, a specific continuous P tap positions (P is an integer of 3 or more and J-2 or less) are set on the primary side. The tap voltage on the secondary side can be switched equivalently by changing the position of consecutive P taps corresponding to the switching of the tap voltage, which is associated with the switching of the tap voltage according to P. ..

In this embodiment, a plurality of taps are provided in the middle of the primary winding, and at least the tap voltage on the primary side can be switched by switching the tap position. There are J tap positions in total, and the tap voltage at a specific continuous P tap position is standardly associated so as to be a P-like tap voltage that can be switched on the primary side. When such a standard association is made, the tap voltage on the secondary side is designed to be a standard voltage. In this state, by changing the entire P tap positions that should be associated for the P tap voltage on the primary side to other continuous P tap positions, the tap voltage on the secondary side is equivalent. Can be switched. That is, since the tap position with respect to the same tap voltage on the primary side is different and the turns ratio changes before and after the change of the above association, the voltage on the secondary side is switched as the tap voltage.

In the transformer with a tap according to one aspect of the present invention, among the P tap positions, the voltage between the taps on the primary side related to the adjacent tap positions is substantially constant, and among the P tap positions, the voltage is substantially constant. When the ratio of the tap voltage on the primary side at the tap position separated by K steps (K is a natural number) in the direction of changing the P tap positions to the tap voltage on the primary side at one tap position is R. By changing the P tap positions in the direction by K steps, the tap voltage on the secondary side is substantially switched to a magnitude of 1 / R times.

In this embodiment, for P consecutive tap positions, the tap position is such that the difference between the tap voltages on the primary side, which changes each time the tap positions differ by one step, that is, the voltage between taps is substantially constant. The number of turns for each is designed. Of the tap positions associated with the P-like tap voltage on the primary side, the tap voltage at the tap position separated by K steps in the direction of changing the P tap positions with respect to the tap voltage at the one tap position of interest. Let the ratio be R. Before and after changing the continuous P tap positions by K steps, even if the tap voltage on the primary side is the same, the number of turns ratio is substantially R times, and the tap voltage on the secondary side is changed. Is set to switch to a size substantially 1 / R times. That is, by keeping the value of K constant and changing the continuous P tap positions in a plurality of ways, the voltage between taps on the secondary side can be made substantially constant.

In the transformer with a tap according to one aspect of the present invention, the J is 9, the P is 5, and the K is 2.

In this embodiment, a plurality of taps having nine tap positions are provided in the primary winding, the tap voltage on the primary side can be switched in five stages, and five consecutive taps on the primary side can be switched. By changing the tap position by two steps, the tap voltage on the secondary side is switched equivalently. Here, the number of steps S in which the tap voltage on the secondary side is equivalently switched by changing the five tap positions on the primary side by a fixed number of steps K is (JP) / K + 1. Therefore, when K is 2, S becomes 3, and the tap voltage on the secondary side can be equivalently switched to 3 stages.

In the tapped transformer according to one aspect of the present invention, the plurality of taps are provided in one or a plurality of tap windings.

In this embodiment, one or a plurality of tap windings are provided at positions different from the main winding in the primary winding, and a plurality of tap positions are formed according to the connection between the taps provided in the tap windings. Will be done. When two or more tap windings are provided, the ampere turn distribution imbalance that occurs between the primary winding and the secondary winding can be suppressed.

According to the present invention, the tap provided on the primary side includes the voltage of P way (P is an integer of 3 or more) on the primary side and the voltage of S way (S is an integer of 2 or more) on the secondary side. It is possible to deal with the number of tap positions smaller than P × S.

It is a connection diagram which shows the connection between windings of a transformer with a tap as a 1st comparative example. It is a figure which shows the characteristic of the transformer with a tap as a 1st comparative example. It is a connection diagram which shows the connection between windings of a transformer with a tap as a 2nd comparative example. It is a figure which shows the characteristic of the transformer with a tap as a 2nd comparative example. It is a connection diagram which shows the connection between windings of a transformer with a tap as a 3rd comparative example. It is a figure which shows the characteristic of the transformer with a tap as a 3rd comparative example. It is a connection diagram which shows the connection between windings of the transformer with a tap which concerns on embodiment. It is a chart which shows the characteristic of the transformer with a tap which concerns on embodiment.

Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments thereof.
(Embodiment)
Before explaining the tapped transformer according to the embodiment, as a comparative example, a tapped transformer that has already been put into practical use and a tapped transformer that can be devised as corresponding to a required voltage switching will be described. ..

FIG. 1 is a connection diagram showing a connection between windings of a tapped transformer 10 as a first comparative example. FIG. 2 is a chart showing the characteristics of the tapped transformer 10 as the first comparative example. The tapped transformer 10 includes delta-connected primary windings 111, 121, 131 and star-connected secondary windings 112, 122, 132. Secondary windings 112, 122, 132 correspond to each of the primary windings 111, 121, 131, respectively.

The primary winding 111 includes main windings 11a and 11a and tap windings 11b, and the tap windings 11b are provided with intermediate taps 11c including four taps numbered 1 to 4. The primary winding 121 includes a main winding 12a, 12a and a tap winding 12b, and the tap winding 12b is provided with an intermediate tap 12c including four taps numbered 1 to 4. The primary winding 131 includes main windings 13a and 13a and tap windings 13b, and the tap windings 13b are provided with intermediate taps 13c including 4 taps numbered 1 to 4.

When the primary (high voltage) side corresponds to the rated voltage and the secondary (low voltage) side corresponds to multiple voltages, the number of turns of the secondary windings 112, 122, 132 (hereinafter referred to as the number of secondary turns) is fixed. In this state, the number of turns of the primary windings 111, 121, 131 (hereinafter referred to as the number of primary turns) is changed by switching the tap position included in the intermediate taps 11c, 12c, 13c provided on the primary side. The output voltage on the side can be switched.

FIG. 2 shows, for example, between the UV lines on the primary side and between the uv lines on the secondary side, but the same applies to the other lines. In the transformer with tap 10, for example, the intermediate tap 11c includes three tap positions. Specifically, when taps with numbers 2, 3, 3, 1, 1 and 4, respectively, are connected, the number of primary turns is 2504, 2390, 2286, respectively. The number of secondary turns is 92. The corresponding voltage on the primary side (hereinafter referred to as the primary voltage) is the rated voltage of 6600V. At the tap position of each number, the output voltage between the lines on the secondary side at each of the three tap positions is as close as possible to the corresponding voltages (hereinafter referred to as secondary voltages) 420V, 440V, 460V on the secondary side. The number of primary turns is designed.

As shown in FIG. 1, when the tap position is switched with the rated 6600V applied between the UV lines, the actual output voltage on the secondary side is switched equivalently to 420.0V, 440. It becomes 0V and 460.1V. In this case, the error with respect to the secondary voltage, that is, the error of the transformation ratio is 0.0020%, 0.0096%, and 0.0134%, respectively, and there is no practical problem. The tapped transformer 10 is designed so as not to be in a state of overexcitation even when the tap position is switched in this way. However, the secondary voltage cannot be switched in three ways while a voltage other than the rated voltage is applied to the primary side.

FIG. 3 is a connection diagram showing a connection between windings of the tapped transformer 20 as a second comparative example. FIG. 4 is a chart showing the characteristics of the tapped transformer 20 as the second comparative example. The tapped transformer 20 includes a delta-connected primary winding 211,221,231 and a star-connected secondary winding 212,222,232. Secondary windings 212, 222, 232 correspond to each of the primary windings 211, 221, 231 respectively.

The primary winding 211 includes main windings 21a, 21a and tap winding 21b, and the tap winding 21b is provided with an intermediate tap 21c including 6 taps numbered 1 to 6. The primary winding 221 includes a main winding 22a, 22a and a tap winding 22b, and the tap winding 22b is provided with an intermediate tap 22c including 6 taps numbered 1 to 6. The primary winding 231 includes a main winding 23a, 23a and a tap winding 23b, and the tap winding 23b is provided with an intermediate tap 23c including 6 taps numbered 1 to 6.

When multiple voltages are supported by multiple tap positions on the primary side (hereinafter, each corresponding primary voltage is also referred to as tap voltage) and the rated voltage is supported on the secondary side, a voltage different from the tap voltage on the primary side. By applying, the output voltage on the secondary side can be switched according to the ratio of the tap voltage and the applied voltage.

FIG. 4 shows, for example, between the UV lines on the primary side and between the uv lines on the secondary side, but the same applies to the other lines. In the transformer with tap 20, the intermediate tap 21c includes five tap positions. Specifically, when taps with numbers 3, 4, 4, 2, 2, 5, 5, 1, 1 and 6, respectively, the primary voltage (that is, tap voltage) is 6750V, 6600V, 6450V, 6300V, It becomes 6150V. The rated secondary voltage is 420V.

As shown in FIG. 3, when the rated 6600V is applied between the UV lines and the tap voltage is switched to a tap position different from the 6600V, the actual output voltage on the secondary side is switched to 410. It becomes .7V, 420.7V, 429.8V, 440.0V, 450.7V. Since the transformer with a tap 20 is not supposed to apply a voltage different from the tap voltage to the primary side, when a voltage higher than the tap voltage is applied to the primary side, it is in a state of overexcitation.

Next, a third comparative example will be described. If the primary side supports multiple voltages and the secondary side also supports multiple voltages, multiple taps are provided on the primary side and tap voltages are applied according to the tap position, and multiple taps are also applied on the secondary side. It is conceivable to provide a secondary voltage (hereinafter, also referred to as a tap voltage as well as the primary side) according to the tap position.

FIG. 5 is a connection diagram showing a connection between windings of the tapped transformer 30 as a third comparative example. FIG. 6 is a chart showing the characteristics of the tapped transformer 30 as a third comparative example. The tapped transformer 30 includes a delta-connected primary winding 311, 321 and 331 and a star-connected secondary winding 312, 322, 332. Secondary windings 312, 322, and 332 correspond to each of the primary windings 311, 321 and 331.

The primary winding 311 includes main windings 31a, 31a and tap winding 31b, and the tap winding 31b is provided with an intermediate tap 31c including 6 taps numbered 1 to 6. The primary winding 321 includes a main winding 32a, 32a and a tap winding 32b, and the tap winding 32b is provided with an intermediate tap 32c including 6 taps numbered 1 to 6. The primary winding 331 includes main windings 33a, 33a and tap winding 33b, and the tap winding 33b is provided with an intermediate tap 33c including 6 taps numbered 1 to 6.

The secondary winding 312 includes a main winding 31d and a tap winding 31e, and the tap winding 31e is provided with an intermediate tap 31f including three taps numbered u1 to u3. The secondary winding 322 includes a main winding 32d and a tap winding 32e, and the tap winding 32e is provided with an intermediate tap 32f including three taps numbered v1 to v3. The secondary winding 332 includes a main winding 33d and a tap winding 33e, and the tap winding 33e is provided with an intermediate tap 33f including three taps numbered w1 to w3.

FIG. 6 shows between the UV lines on the primary side and between the uv lines on the secondary side, but the same applies to the other lines. In the transformer with a tap, for example, the intermediate tap 31c includes five tap positions. Specifically, when taps with numbers 3, 4, 4, 2, 2, 5, 5, 1, 1 and 6, respectively, the primary turns are 2338, 2286, 2234, 2182, 2130, and the primary voltage is (Tap voltage) becomes 6750V, 6600V, 6450V, 6300V, 6150V.

On the secondary side, each of the taps numbered u1, u2, and u3 corresponds to the tap position. For example, when switching to the tap positions of u3 (v3), u2 (v2), and u1 (v1), the secondary turns are 84, 88, and 92, respectively, and between u3-v3, u2-v2, and u1-v1. The secondary voltage (tap voltage) between the lines is 420V, 440V, and 460V, respectively. As shown in FIG. 6, the actual output voltage on the secondary side has an error with respect to the tap voltage, that is, an error of the transformation ratio within 0.02%.

According to the above-mentioned third comparative example, the tap voltage can be switched in 5 ways on the primary side and 3 ways on the secondary side. However, as shown in FIG. 6, the number of combinations of tap positions is 15 and it is complicated, and it is necessary to reconnect the external wiring to switch the tap position on the secondary side, so that the scale is structurally large. Is a drawback. Hereinafter, the tapped transformers capable of eliminating the drawbacks of the tapped transformers 10, 20, and 30 according to the first comparative example to the third comparative example will be described.

FIG. 7 is a connection diagram showing a connection between windings of the tapped transformer 40 according to the embodiment. FIG. 8 is a chart showing the characteristics of the tapped transformer 40 according to the embodiment. The tapped transformer 40 includes a delta-connected primary winding 411,421,431 and a star-connected secondary winding 421,422,432. Secondary windings 421,422,432 correspond to each of the primary windings 211,221,231.

The primary winding 411 includes main windings 41a, 41a, 41a and tap windings 41b, 41b, and the tap windings 41b, 41b are 6 taps numbered 1 to 6, 7 to 12, respectively. Intermediate taps 41c and 41d including the above are provided. The primary winding 421 includes main windings 42a, 42a, 42a and tap windings 42b, 42b, and the tap windings 42b, 42b are 6 taps numbered 1 to 6, 7 to 12, respectively. Intermediate taps 42c and 42d including the above are provided. The primary winding 431 includes main windings 43a, 43a, 43a and tap windings 43b, 43b, and the tap windings 43b, 43b have 6 taps numbered 1 to 6, 7 to 12. Intermediate taps 43c and 43d including the inner taps 43c and 43d are provided.

The intermediate taps 41c and 41d are provided separately for the tap windings 41b and 41b to suppress the imbalance of the ampere turn distribution and prevent local overheating, increase in loss and increase in internal mechanical force. To do. One intermediate tap may be provided in one tap winding, or three or more intermediate taps may be dispersed in three or more tap windings. The same applies to the other intermediate taps 42c, 42d and 43c, 43d.

FIG. 8 shows, for example, between the UV lines on the primary side and between the uv lines on the secondary side, but the same applies to the other lines. In the transformer with tap 40, for example, each of the intermediate taps 41c and 41d includes five tap positions. Specifically, taps with numbers 9 and 10 are connected with the intermediate tap 41d, and taps with numbers 3 and 4, 4 and 2, 2 and 5, 5 and 1, 1 and 6 are connected with the intermediate tap 41c. When each is connected, the number of primary turns is 2561,254, 2446, 2390, 2336. Further, the taps with numbers 1 and 6 were connected with the intermediate tap 41c, and the taps with numbers 9 and 10, 10 and 8, 8 and 11, 11 and 7, 7 and 12, respectively, were connected with the intermediate tap 41d. In this case, the number of primary turns is 2336, 2284, 2231, 182, 2130. The nine tap positions determined in this way are the positions from t1 to t9 in order from the top of FIG. The number of secondary turns is 92.

Of the nine tap positions from t1 to t9, for example, the primary voltages (tap voltages) at the five consecutive tap positions from t1 to t5 are 6750V, 6600V, 6450V, 6300V, and 6150V, respectively. Standard mapping is done. In this case, the number of primary turns at each tap position is set so that the secondary voltage between the lines, that is, the equivalent tap voltage, is as close as possible to the rated 420 V at 50 Hz with respect to each tap voltage on the primary side. This 420V is the rated tap voltage. The five tap positions to which the above standard association is made may be other five tap positions continuous from other than the uppermost tap position t1.

For example, standard correspondence may be made so that the tap voltages on the primary side at the tap positions from t3 to t7 are 6750V, 6600V, 6450V, 6300V, and 6150V, respectively. In this case, FIG. 8 can be seen as the number of primary turns at each tap position is set so that the output voltage on the secondary side approaches the rated secondary voltage of 440 V at 60 Hz as much as possible. This 440V is the rated tap voltage.

From the state where the above 5 tap voltages (6750V, 6600V, 6450V, 6300V, 6150V) are standardly associated with the specific 5 tap positions, the 5 tap voltages should be associated with the 5 tap voltages. When the entire tap position is changed to five consecutive tap positions, the ratio of the number of turns of the primary turn to the number of secondary turns changes, so that the secondary voltage (tap voltage) is switched equivalently. That is, before and after the change in the correspondence between the five tap voltages and the five tap positions, the number of secondary turns is constant, whereas the number of primary turns corresponding to the same tap voltage on the primary side changes. Since the turns ratio also changes, the tap voltage on the secondary side switches.

Specifically, the tap voltage of each of 6750V, 6600V, 6450V, 6300V, and 6150V is changed from the state in which the tap voltage is associated with the tap position of t1, t2, t3, t4, t5 to the tap position of t3, t4, t5, t6, t7. A case where the state is changed to be associated will be described. First, when the tap voltage of 6750V is changed from the state associated with the tap position of t1 to the state associated with the tap position of t3, the number of primary turns is reduced from 2561 turns to 2446 turns. Therefore, when the tap position is switched from t1 to t3 with the setting that the voltage of 6750V is applied to each of the UV, VW, and WU of the primary windings 411,421,431, the turns ratio. 2446/2561 times, and the secondary voltage of the secondary windings 421,422,432 between the uv line, the vw line, and the wu line is switched from 420V to 440V. The multiple of the number of turns ratio, 2446/2561 (= 0.9551), is at the tap position of t3, which is separated by two steps in the direction of changing the correspondence of the tap position with respect to the tap voltage of 6750V at the tap position of t1. It is substantially the same as the ratio of tap voltage of 6450V (= 0.9556).

Similarly, when the tap position is switched from t2 to t4 with the setting that a voltage of 6600V is applied to each primary winding, the number of primary turns decreases from 2504 turns to 2390 turns, and the turns ratio decreases 2390/2504 times. Then, the secondary voltage between the lines of each secondary winding is switched from 420V to 440V. When the tap position is switched from t3 to t5 with the setting that a voltage of 6450V is applied to each primary winding, the number of primary turns decreases from 2446 turns to 2336 turns, and the turns ratio decreases 2336/2446 times, respectively. The secondary voltage between the lines of the secondary winding switches from 420V to 440V. When the tap position is switched from t4 to t6 with the setting that a voltage of 6300V is applied to each primary winding, the number of primary turns decreases from 2390 turns to 2284 turns, and the turns ratio decreases 2284/2390 times, respectively. The secondary voltage between the lines of the secondary winding switches from 420V to 440V. When the tap position is switched from t5 to t7 with the setting that a voltage of 6150V is applied to each primary winding, the number of primary turns decreases from 2336 turns to 2231 turns, and the turns ratio decreases 2231/2336 times, respectively. The secondary voltage between the lines of the secondary winding switches from 420V to 440V. The tap voltage of 440 V on the secondary side switched in this way is a total capacity tap voltage that can be used at the rated capacity.

The state in which the tap voltages of 6750V, 6600V, 6450V, 6300V, and 6150V are associated with the tap positions of t1, t2, t3, t4, and t5 to the tap positions of t5, t6, t7, t8, and t9. The same applies when the value is changed to. Specifically, when the tap position is switched from t1 to t5 with the setting that a voltage of 6750V is applied to each primary winding, the number of primary turns is reduced from 2561 turns to 2336 turns, and the turns ratio is 2336/2561 times. As it decreases, the secondary voltage between the lines of each secondary winding switches from 420V to 460V. When the tap position is switched from t2 to t6 with the setting that a voltage of 6600V is applied to each primary winding, the number of primary turns decreases from 2504 turns to 2284 turns, and the turns ratio decreases 2284/2504 times, respectively. The secondary voltage between the lines of the secondary winding switches from 420V to 460V. When the tap position is switched from t3 to t7 with the setting that a voltage of 6450V is applied to each primary winding, the number of primary turns decreases from 2446 turns to 2231 turns, and the turns ratio decreases 2231/2446 times, respectively. The secondary voltage between the lines of the secondary winding switches from 420V to 460V. When the tap position is switched from t4 to t8 with the setting that a voltage of 6300V is applied to each primary winding, the number of primary turns decreases from 2390 turns to 2182 turns, and the turns ratio decreases 2182/2390 times, respectively. The secondary voltage between the lines of the secondary winding switches from 420V to 460V. When the tap position is switched from t5 to t9 with the setting that a voltage of 6150V is applied to each primary winding, the number of primary turns decreases from 2336 turns to 2130 turns, and the turns ratio decreases 2130/2336 times, respectively. The secondary voltage between the lines of the secondary winding switches from 420V to 460V. The tap voltage of 460 V on the secondary side switched in this way is the total capacity tap voltage.

The tap voltages of 6750V, 6600V, 6450V, 6300V, and 6150V are associated with the tap positions of t5, t6, t7, t8, and t9 from the state of being associated with the tap positions of t3, t4, t5, t6, and t7. The same applies when the state is changed to. For example, when the tap position is switched from t3 to t5 with the setting that a voltage of 6750V is applied to each primary winding, the number of primary turns is reduced from 2446 turns to 2336 turns, and the turns ratio is reduced to 2336/2446 times. , The secondary voltage between the lines of each secondary winding switches from 440V to 460V. The magnification of the turns ratio in this case, 2336/2446 (= 0.9550), is at the tap position of t5, which is separated by two steps in the direction of changing the correspondence of the tap position with respect to the tap voltage of 6750V at the tap position of t3. It is substantially the same as the ratio of tap voltage of 6450V (= 0.9556).

Further, the tap voltages of 6750V, 6600V, 6450V, 6300V, and 6150V are associated with the tap positions of t1, t2, t3, t4, and t5 from the state of being associated with the tap positions of t3, t4, t5, t6, and t7. The same applies to the description of the case where the state is changed to the above. For example, when the tap position is switched from t7 to t5 with the setting that a voltage of 6150V is applied to each primary winding, the number of primary turns increases from 2231 turns to 2336 turns, and the turns ratio increases 2336/2231 times. , The secondary voltage between the lines of each secondary winding switches from 440V to 420V. The magnification of the turns ratio in this case, 2336/2231 (= 1.0471), is at the tap position of t5, which is separated by two steps in the direction of changing the correspondence of the tap position with respect to the tap voltage of 6150 V at the tap position of t7. It is substantially the same as the ratio of tap voltage of 6450V (= 1.0488).

Similarly, when the tap position is switched from t6 to t4 with the setting that a voltage of 6300V is applied to each primary winding, the number of primary turns increases from 2284 turns to 2390 turns, and the turns ratio increases 2390/2284 times. Then, the secondary voltage between the lines of each secondary winding is switched from 440V to 420V. When the tap position is switched from t5 to t3 with the setting that a voltage of 6450V is applied to each primary winding, the number of primary turns increases from 2336 turns to 2446 turns, and the turns ratio increases 2446/2336 times, respectively. The secondary voltage between the lines of the secondary winding switches from 440V to 420V. When the tap position is switched from t4 to t2 with the setting that a voltage of 6600V is applied to each primary winding, the number of primary turns increases from 2390 turns to 2504 turns, and the turns ratio increases 2504/2390 times, respectively. The secondary voltage between the lines of the secondary winding switches from 440V to 420V. When the tap position is switched from t3 to t1 with the setting that a voltage of 6750V is applied to each primary winding, the number of primary turns increases from 2446 turns to 2561 turns, and the turns ratio increases 2561/2446 times, respectively. The secondary voltage between the lines of the secondary winding switches from 440V to 420V. The tap voltage of 420 V on the secondary side switched in this way is the total capacity tap voltage.

The association between the five tap voltages (6750V, 6600V, 6450V, 6300V, 6150V) shown in FIG. 8 and the five consecutive tap positions is made two steps at a time in the nine tap positions (t1 to t9). The description of the case of changing is as described above. Although 5 consecutive tap positions are shown in FIG. 8, the tap voltage on the primary side is actually set to 6750V, 6600V, 6450V, 6300V, 6150V at each of the 5 tap positions. In order to set the next voltage (tap voltage) to exactly 420V, 440V, and 460V, respectively, it is necessary to set the calculated primary winding number to a non-integer value different from the value shown in FIG.

Therefore, in FIG. 8, for the tap positions t1, t2, t8, and t9 having one calculated winding value, the taps having two or three calculated winding values are rounded off to the nearest whole number. For positions t3 to t7, a value rounded to the nearest whole number of the winding values was adopted. Therefore, as shown in FIG. 8, the actual output voltage on the secondary side is a value slightly deviated from the secondary voltage (tap voltage) of 420V, 440V, 460. Even so, the error with respect to the secondary voltage, that is, the error of the transformation ratio is within ± 0.17%.

In the above example, an example in which the tap positions of five consecutive taps associated with the five tap voltages are changed by two steps to switch the tap voltage on the secondary side to a different voltage by 20 V has been described. It is not limited to. For example, it is possible to change the tap positions of five consecutive taps one step at a time to switch the tap voltage on the secondary side to a different voltage by 10 V. In this case, the tap voltage on the secondary side can be switched to 420V, 430V, 440V, 450V, 460V. Further, for example, when the number of all tap positions is set to 11, and the tap voltage on the secondary side is switched to a different voltage by 20 V by changing the tap positions of five consecutive tap positions by two steps, the tap voltage on the secondary side is changed. For example, it is possible to switch in five ways of 400V, 420V, 440V, 460V, and 480V.

Furthermore, the number of all tap positions is set to 5, the three consecutive tap positions are changed one step at a time or only two steps, the tap voltage on the primary side is switched to three ways, and the tap voltage on the secondary side is changed to three ways. Alternatively, it may be possible to switch in two ways. Set the number of all tap positions to 6, change the four consecutive tap positions one step at a time or only two steps, switch the tap voltage on the primary side to four ways, and change the tap voltage on the secondary side to three ways or two. It may be possible to switch according to the street. In addition, on the premise that the number of all tap positions is 5 or more, the tap voltage on the primary side can be switched to 3 or more ways, and the tap voltage on the secondary side can be switched to 2 or more ways. Can be accommodated.

Finally, the formula for aggregating the number of taps will be described. First, the following number of characters is defined.
Number of all tap positions: J
Primary tap voltage number: P
Secondary tap voltage number: S

Of the J tap positions, the number obtained by adding 1 to the number of cases where the continuous P tap positions associated with the P tap voltages can be changed to other P tap positions is secondary. Since the maximum number of side tap voltages S | S | max, the following equation (1) holds.
| S | max = JP + 1 ... (1)

When changing P tap positions to other P tap positions and changing by K steps (K is a natural number), S is generally expressed by the following equation (2). However, the condition is that (JP) is divisible by K. Equation (2) is transformed as in equation (3).
S = (JP) / K + 1 ... (2)
J = P + K (S-1) ... (3)

Here, when two sets of intermediate taps having the same configuration such as the intermediate taps 41c and 41d shown in FIG. 7 are provided, the number J of all tap positions is an odd number. Therefore, if the number of tap voltages P on the primary side is an odd number, (JP) is divisible by at least 2. In the present embodiment, since J = 9 and P = 5, (JP) is divisible by 1, 2, and 4, but by setting K = 2, the secondary tap voltage number S is set to 3. did. That is, by taps including nine tap positions, it is possible to switch between 5 × 3 tap voltage combinations on the primary side and the secondary side.

As described above, according to the present embodiment, intermediate taps 41c and 41d, 42c and 42d, 43c and 43d including a plurality of taps are provided in the middle of each of the primary windings 411, 421 and 431 of the transformer 40 with taps. By switching the tap positions t1 to t9, it is possible to switch at least the tap voltage on the primary side. There are nine tap positions in total, and the tap voltage at five specific continuous tap positions t1 to t5 is five different tap voltages 6750V, 6600V, 6450V, 6300V, 6150V that can be switched on the primary side. It is associated as standard as there is. When such a standard association is made, for example, the tap voltage 420V on the secondary side is designed to be the rated voltage. In this state, by changing the whole of the five tap positions t1 to t5 to be associated with the five tap voltages on the primary side to the other five consecutive tap positions t3 to t5, the secondary side The tap voltage can be equivalently switched from 420V to 440V. Further, by changing the whole of the five tap positions t1 to t5 to be associated with the five tap voltages on the primary side to the other five consecutive tap positions t5 to t9, the tap voltage on the secondary side is changed. Can be equivalently switched from 420V to 460V. That is, since the tap position with respect to the same tap voltage on the primary side is different and the turns ratio changes before and after the change of the above association, the voltage on the secondary side is switched as the tap voltage. Therefore, the intermediate taps 41c and 41d, 42c and 42d, 43c and 43d provided on the primary side are included in the five tap voltages on the primary side and the three tap voltages on the secondary side (less than 5 × 3). ) It is possible to correspond by 9 tap positions.

Further, according to the embodiment, for five consecutive tap positions, the difference between the tap voltages on the primary side that changes each time the tap positions differ by one step, that is, the voltage between taps becomes a substantially constant 150 V. , The number of turns for each tap position is designed. Of the tap positions t1 to t5 associated with the five tap voltages on the primary side, the tap positions t3 separated by two steps in the changing direction of the five tap positions with respect to the tap voltage 6750V at the tap position t1 of interest. The ratio (= 6450/6750) of the tap voltage 6450V in the above is R. Before and after changing the five consecutive tap positions by two steps, the magnification of the turns ratio (= 2446/2561) is substantially R (= 6450 /) even if the tap voltage 6750V on the primary side is the same. The tap voltage on the secondary side is substantially switched to a magnitude of 1 / R (= 6750/6450) times so as to be 6750) times. That is, by setting the value of K to 2 and changing the five consecutive tap positions in three ways, the voltage between taps on the secondary side can be made substantially constant 20 V.

Further, according to the embodiment, intermediate taps 41c and 41d, 42c and 42d, 43c and 43d, respectively, which include a plurality of taps having nine tap positions, are provided in the primary windings 411, 421 and 431, respectively, and are primary. The tap voltage on the side can be switched in five stages, and the tap voltage on the secondary side is equivalently switched by changing the five consecutive tap positions t1 to t5 on the primary side in two stages at a time. Here, the number of steps S in which the tap voltage on the secondary side is equivalently switched by changing the five tap positions t1 to t5 on the primary side by a fixed number of steps K is (JP) from the equation (2). / K + 1. Therefore, when K is 2, S becomes 3, and the tap voltage on the secondary side can be equivalently switched to 3 stages.

Further, according to the embodiment, there are a plurality of tap windings 41b and 41b, 42b and 42b, 43b and 43b at positions different from the main windings 41a, 42a and 43a in the primary windings 411, 421 and 431, respectively. , Nine tap positions are provided according to the connections between the taps included in the intermediate taps 41c and 41d, 42c and 42d, 43c and 43d provided in the tap windings 41b and 41b, 42b and 42b, 43b and 43b, respectively. It is formed. By having two or more tap windings 41b and 41b, 42b and 42b, 43b and 43b in the primary windings 411, 421 and 431, respectively, the primary windings 411, 421 and 431 and the secondary windings 421 and 422 respectively. , The imbalance of the ampere turn distribution that occurs between 432 can be suppressed.

The embodiments disclosed this time should be considered as exemplary in all respects and not restrictive. The scope of the present invention is indicated by the scope of claims, not the above-mentioned meaning, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims. Also, the technical features described in each embodiment can be combined with each other.

10, 20, 30, 40 Tap transformers 111, 121, 131, 211, 221, 231, 331, 321, 331 Primary winding 112, 122, 132, 212, 222, 232, 312, 322, 332 Secondary Windings 11a, 12a, 13a, 21a, 22a, 23a, 31a, 31d, 32a, 32d, 33a, 33d Main windings 11b, 12b, 13b, 21b, 22b, 23b, 31b, 31e, 32b, 32e33b, 33e Tap Winding 11c, 12c, 13c, 21c, 22c, 23c, 31c, 31f, 32c, 32f, 33c, 33f Intermediate tap t1, t2, t3, t4, t5, t6, t7, t8, t9 Tap position

Claims (4)

A transformer with a tap that has multiple taps in the middle of the primary winding and can switch the tap voltage on the primary side.
The plurality of taps include J tap positions (J is an integer of 5 or more).
Of the J tap positions, specific continuous P tap positions (P is an integer of 3 or more and J-2 or less) are associated with each other for switching the tap voltage according to P on the primary side.
A transformer with a tap that can equivalently switch the tap voltage on the secondary side by changing the continuous P tap positions associated with the switching of the tap voltage. Of the P tap positions, the voltage between taps on the primary side related to the adjacent tap positions is substantially constant.
Of the P tap positions, the tap voltage on the primary side at the tap position separated by K steps (K is a natural number) in the direction of changing the P tap positions with respect to the tap voltage on the primary side at one tap position. When the ratio of is R, the tap voltage on the secondary side is substantially switched to a magnitude of 1 / R times by changing the tap positions of the P pieces in the direction by K steps. Described transformer with tap. The J is 9,
The P is 5,
The transformer with a tap according to claim 2, wherein K is 2. The transformer with a tap according to any one of claims 1 to 3, wherein the plurality of taps are provided on one or a plurality of tap windings.

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