JPH06261458A - Parallel operating method for transformer - Google Patents

Abstract

PURPOSE:To make it possible to adequately distribute a load current in response to respective rated capacities when operating in parallel three or more transformers having different impedances. CONSTITUTION:N units (N>=3) to be operated in parallel, for example, (2N-3) units, that is, 3 units of single-phase autotransformers AT1, AT2 and AT3 are connected to the primary side or secondary side of 3 units of single-phase transformers T1, T2 and T3. And the distribution of load current of the single- phase transformers T1 to T3 is controlled to a proper value in response to the reciprocal ratio of the number of turns by adequately adjusting the voltage ratio, that is, the number of turns N1/N2 respectively of each single-phase autotransformers AT1 to AT3. By doing this, the load current can be properly distributed in response to the rated capacity of each transformer when operating three or more transformers in parallel having different impedances.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a plurality of autotransformer transformers in parallel when three or more transformers having different impedances are operated in parallel so as to correspond to the rated capacity of each transformer. The present invention relates to a parallel operation method of transformers capable of appropriately distributing the voltage.

[0002]

2. Description of the Related Art When two transformers having different impedances are operated in parallel, the distribution of load current differs from the ratio of their rated capacities. Therefore, an autotransformer is used to correct the distribution of the load current so that the rated capacity ratio is obtained ("Transformer Engineering" LF Blume et al., Corona Publishing, 169-170). page).

[0003]

As described above, a method of operating two transformers having different impedances in parallel has been disclosed. However, there are cases in which three or more transformers having different impedances are operated in parallel, and in such a case, a method for appropriately distributing the load current according to each rated capacity has not been shown.

The present invention has been made to solve the above problems, and when three or more transformers having different impedances are operated in parallel, the load current is properly adjusted according to the rated capacity of each transformer. The purpose is to obtain a parallel operation method of transformers that can be distributed.

[0005]

SUMMARY OF THE INVENTION A parallel operation method of transformers according to the present invention includes (2N-3) single transformers on the primary side or secondary side of N (N ≧ 3) transformers that are operated in parallel. The transformers are connected and the voltage ratio of each autotransformer is adjusted so that the load sharing ratio of each transformer corresponds to its rated capacity.

[0006]

In the present invention, N (N ≧ N
3) (2N-3) autotransformer transformers are connected to the primary side or secondary side of the transformers, and the current ratio is adjusted by adjusting the voltage ratio of each autotransformer. Thus, the load sharing ratio of each transformer is adjusted to correspond to the rated capacity ratio.

[0007]

Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings. Figure 1
FIG. ₃ is a connection diagram showing a parallel operation method of transformers according to the first embodiment, and T _{1 to} T ₃ are three single-phase transformers that are operated in parallel, each having different impedance. The primary winding is connected in parallel, and the secondary winding is three single-phase autotransformer ATs.
_{1 to} AT ₃ are connected in parallel.

Now, the single-phase autotransformers AT _{1 to} AT ₃ will be described with reference to FIG. The currents I ₁ and I ₂ flow into the terminals 1 and 2, respectively, and the current I ₃ flows out from the intermediate terminal 3, and the number of turns of the winding A between the terminals 1 and 3 is N ₁ and between the terminals 2 and 3. If the number of turns of the winding B is N _2, and the ampere-turns of the windings A and B are equal, that is, N ₁ I ₁ = N ₂ I ₂ , the impedances of the single-phase autotransformers AT _{1 to} AT ₃ are: It is the leakage impedance between the windings A and B, which is the smallest value.

On the other hand, when the ampere-turns of the windings A and B are not equal, that is, N ₁ I ₁ ≠ N ₂ I ₂ , or from terminal 1 to terminal 2.
When a current is going to flow in the (or vice versa) direction, the impedance of the single-phase autotransformers AT _{1 to} AT ₃ acts as the excitation impedance of the iron core, and its value is the leakage between windings A and B. It is orders of magnitude larger than the impedance. Therefore, the single-phase autotransformers AT _{1 to} AT ₃ have terminals 1, 2
Has a function of limiting the ratio of the currents I ₁ and I ₂ flowing into (or flowing out of) to the inverse ratio of the windings N ₁ and N ₂ of the windings A and B (I ₁ / I ₂ = N ₂ / N ₁ ). is doing.

[0010] Therefore, by the single-phase autotransformer AT ₁ to AT ₃ voltage ratio or a turns ratio N ₁ / N ₂ is appropriately adjusted each impedance of each single-phase transformer T ₁ through T ₃ is Even if they are different, the distribution of each load current can be controlled to an appropriate value corresponding to the inverse ratio of the number of turns. In the case of FIG. 1, the voltage ratio (turn ratio) of each of the single-phase autotransformers AT _{1 to} AT ₃ is set to 1: 1, 1: 1 and 3: 1. Assuming that the current of 6 ”flows in,
The AT ₁ divided into "1" and "1" flows "2", AT ₃
"4" flows in and split into "1" and "3". Therefore,
"1" flows into AT ₂ from both ends, and "2" flows out. Therefore, the load current of the single-phase transformer T ₁ through T ₃ may be the one corresponding to "1", "2", "3", and the rated capacity. In addition, single-phase autotransformer AT ₁ ~
Although AT ₃ is connected to the secondary side of the single-phase transformers T _{1 to} T ₃ , it may be connected to the primary side.

Second Embodiment In the first embodiment, three single-phase transformers AT _{1 to} AT ₃ are connected to the _three single-phase transformers T _{1 to} T ₃ , but N is set to N> 3 and N units are set. The same effect can be obtained by connecting (2N-3) single-phase autotransformers to the single-phase transformer.

Embodiment 3 FIG. 3 is a connection diagram showing a parallel operation method of transformers according to Embodiment 3, where T _{4 to} T ₆ are three three-phase transformers operated in parallel, each having different impedance. . The primary windings are connected in parallel, and the secondary windings are connected in parallel via three three-phase autotransformers AT _{4 to} AT ₆ . here,
Each of the three-phase autotransformers AT _{4 to} AT ₆ is a single-phase autotransformer A.
It has the same function as T _{1 to} AT _3, and the distribution of the load current can be adjusted by adjusting the turns ratio, and the rated capacity can be dealt with. Also in the third embodiment, the three-phase autotransformers AT _{4 to} AT ₆ may be connected to the primary side of the three-phase transformers T _{4 to} T ₆ .

[0013] I connected EXAMPLE 4 Three-phase autotransformer of three to three-phase transformer T ₄ through T ₆ of the three in the third embodiment device AT ₄ to AT _6, N base N as N> 3 The same effect can be obtained by connecting (2N-3) three-phase autotransformers to the three-phase transformer.

[0014]

As described above, according to the present invention, N (N
≥3) (2N-3) autotransformers are connected to the primary side or secondary side of the transformers, and the load sharing ratio of each transformer is adjusted by adjusting the voltage of the autotransformer. The load sharing ratio of the transformer can be made to correspond to the rated capacity ratio.

[Brief description of drawings]

FIG. 1 is a connection diagram showing a parallel operation method of transformers according to a first embodiment.

FIG. 2 is a connection diagram of the single-phase autotransformer according to the first embodiment.

FIG. 3 is a connection diagram showing a parallel operation method of transformers according to a third embodiment.

[Explanation of symbols]

T ₁ ~T ₃ ... single-phase transformer T ₄ ~T ₆ ... three-phase transformer AT ₁ ~AT ₃ ... single-phase autotransformer AT ₄ ~AT ₆ ... three-phase autotransformer

Claims (1)

[Claims] 1. (2N-3) autotransformer transformers are connected to the primary side or secondary side of N (N ≧ 3) transformers operating in parallel, and the voltage ratio of each autotransformer is adjusted. A parallel operation method of transformers, characterized in that the load sharing ratio of each transformer is adjusted so as to correspond to each rated capacity.