JPH031895B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a three-phase power distribution circuit, particularly a three-phase 6600V power distribution circuit.
3 is suitable for distributing power by stepping down the voltage to 400V in 3 sets.
It relates to phase distribution circuits.

[Summary of the Invention] The present invention provides a three-phase power distribution circuit that connects a power distribution transformer and a power receiving transformer with a power distribution line to distribute three-phase power. The receiving transformer consists of two normal single-phase transformers without a neutral point, and the two distribution transformers have a neutral point. By connecting both ends of the secondary winding to the two primary windings of the power receiving transformer via the power distribution line, and by commonly grounding the neutral point of the two secondary windings of the power distribution transformer, A distribution transformer is constructed using a commonly used single-phase transformer without causing a rise in equipment costs, and three-phase power can be distributed using a neutral point grounding system.

[Prior art] Two distribution transformers and two power receiving transformers each.
A V-connection type three-phase power distribution circuit shown in FIG. 6 is known as a circuit configured with one single-phase transformer and distributing three-phase power. In this distribution circuit, the distribution transformer Ts' consists of two single-phase transformers Ta' and Tb', and the power receiving transformer Tr' consists of two single-phase transformers Tc' and Td'. There is. The primary windings Ta1' and Tb1' and the secondary windings Ta of the two single-phase transformers Ta' and Tb' that constitute the distribution transformer Ts', respectively.
2' and Tb2' are both V-connected, and the power receiving transformer Tr'
The primary windings Tc1', Td1' and the secondary windings Tc2', Td2' of the two single-phase transformers Tc', Td' constituting the transformer are also V-connected. and V of the distribution transformer
The connected primary windings Ta1' and Tb1' are connected to the three-phase distribution lines Lsu to Lsw on the power supply side, and the V-connected secondary windings Ta2' and Tb2' of the distribution transformer and the receiving transformer V-connected primary winding Tc1', Td
1' are connected via three-phase power distribution lines Lu to Lw. In addition, the V-connected secondary windings Tc2' and Td2' of the power receiving transformer are connected to the three-phase distribution line on the load side.
Connected to Lru to Lrw.

According to the above-mentioned power distribution circuit, a power distribution transformer and a power receiving transformer can be configured by combining two normal single-phase transformers, so that equipment costs can be reduced. Therefore, the above-mentioned power distribution circuit has a relatively small capacity and is often used when converting high voltage to low voltage and distributing power.

[Problems to be solved by the invention] By the way, in depopulated areas, when distributing electricity to electricity consumers who use less electricity, it is necessary to reduce the efficiency of equipment investment by distributing electricity at high voltage to the terminals of electricity-intensive households. A system that steps down the voltage from 6,600V to 400V and distributes it at the terminal side is being considered.

However, when distributing power at 400V, the neutral point of the distribution line must be grounded according to technical standards (Article 23 of the Electrical Equipment Technical Standards), so when distributing three-phase power, single-phase It was not possible to use the power distribution circuit shown in Figure 6, which uses the single-phase transformer that was used for power distribution and is V-connected.
There was a problem in that a three-phase transformer with a star-connected secondary winding and a neutral point had to be specially prepared, which increased equipment costs.

An object of the present invention is to configure a power distribution transformer and a power receiving transformer using a commonly used single-phase transformer, and to perform power distribution with a grounded neutral point without causing a rise in equipment costs. The object of the present invention is to provide a three-phase power distribution circuit that enables the following.

[Means for Solving the Problems] As shown in FIG. 1 showing one embodiment of the present invention, the present invention is directed to a winding coil provided with primary windings Ta1, Tb1 and neutral point taps N1, N2. Next winding Ta2,
Two distribution single-phase transformers Ta and Tb with Tb2
A distribution transformer Ts is formed by V-connecting the primary windings of both distribution single-phase transformers, and primary windings Tc1 and Td.
A power receiving transformer Tr comprising two power receiving single phase transformers Tc and Td having primary and secondary windings Tc2 and Td2, and V-connecting the secondary windings of both power receiving single phase transformers.
It is equipped with.

The V-connected primary winding Ta of the above distribution transformer Ts
1, Tb1 are connected to the three-phase distribution lines Lsu to Lsw on the power supply side, and the two secondary windings Ta2 and Tb2 of the distribution transformer Ts are connected to the lines L1, L2 and L3, L, respectively.
Different primary windings of the power receiving transformer Tc1 through 4
and Td1 (or Td1 and Tc1). The two secondary windings of a distribution transformer
The neutral point taps N1 and N2 of Ta2 and Tb2 are grounded, and the V-connected secondary winding Tc of the power receiving transformer Tr
2, Td2 is connected to the load side 3-phase distribution line.

[Operation of the invention] With the above configuration, a distribution transformer is constructed by combining two single-phase three-wire distribution single-phase transformers having the same specifications, and a neutral voltage is established on the secondary side of the distribution transformer. The point can be grounded, and the power receiving transformer can be configured using two single-phase transformers with the same specifications. Therefore, there is no need to specially prepare a three-phase transformer with a star-connected secondary winding, and neutral point grounding type power distribution can be performed that complies with technical standards without increasing equipment costs. Can be done.

[Example] Figures 1 and 2 are a system diagram showing the overall configuration of an example of the three-phase power distribution circuit of the present invention and a connection diagram showing specific connections, respectively. In the figure, Ts is for power distribution. The transformer, Tr, is a power receiving transformer.

The distribution transformer Ts includes a single-phase transformer Ta having a primary winding Ta1 and a secondary winding Ta2, and a primary winding Tb.
It consists of two single-phase transformers of the same purpose, with a single-phase transformer Tb having primary and secondary windings Tb2, and from the position where the entire winding of each of the secondary windings Ta2 and Tb2 is divided into two. Neutral point taps N1 and N2 are drawn out. These single-phase transformers Ta and Tb are:
Since single-phase transformers that are manufactured in large numbers for single-phase three-wire power distribution can be used as they are, the cost of power distribution transformers does not rise.

The primary windings Ta1 and Tb1 of the distribution transformer are V-connected and connected to the 6600V power supply side three-phase distribution lines Lsu to Lsw. In addition, the secondary winding Ta2,
Neutral taps N1 and N2 of Tb2 are connected to each other and grounded.

The power receiving transformers Tc and Td each have a primary winding.
It consists of two single-phase transformers Tc and Td having the same specifications and having Tc1 and Td2 and secondary windings Tc2 and Td2. Primary winding Tc1 of this power receiving transformer
and Td1 are independent windings, and the secondary windings Tc2,
Td2 is V-connected and connected to the load-side three-phase distribution lines Lru to Lrw.

Both ends of the secondary winding Ta2 of the distribution voltage generator are connected to both ends of the primary winding Tc1 of the power receiving transformer via lines L1 and L2, respectively.
Both ends of the next winding Tb2 are connected to lines L3 and L4, respectively.
It is connected to both ends of the primary winding Td1 of the power receiving transformer via.

In addition, contrary to the above, the secondary winding Ta2 of the distribution transformer
may be connected to both ends of the primary winding Td1 of the power receiving transformer, and both ends of the secondary winding Tb2 of the distribution transformer may be connected to both ends of the primary winding Tc1 of the power receiving transformer. .

The distribution transformer Ts is the power supply side distribution line Lsu to Lsw
The voltage of 6600V supplied through the converter is stepped down to 400V and supplied to the power receiving transformer Tr. Power receiving transformer
The Tr steps down this 400V voltage to, for example, 200V and supplies it to important homes.

When configured as above, the 400V distribution line is
Since the neutral point is grounded on the distribution transformer side,
Can be adapted to technical standards. In addition, the distribution transformer can be configured by combining two single-phase three-wire distribution transformers with center taps.
This can be done without increasing equipment costs.

In the above embodiment, a single-phase three-wire distribution transformer having a center tap is used as the single-phase transformer Tc or Td constituting the power receiving transformer Tr. Alternatively, if Q is grounded, three-phase, four-wire power distribution can be performed using the lines Lru to Lrw and the line drawn out from the center tap P or Q.

Furthermore, if the line Lrv is grounded at point R in FIG. 2, three-phase three-wire power distribution can be performed.

FIG. 3 shows another embodiment of the present invention,
In this embodiment, the secondary winding Ta2 of the distribution transformer Ts
The neutral points N1 and N2 of Tb2 are grounded, and the line is connected from the connection point of the neutral points N1 and N2.
Pulling out Ln. If a line Ln is provided for this purpose,
When the secondary voltage of the distribution transformer Ts is 400V, the lines L1, L3 and Ln can constitute one three-phase distribution line with a voltage of 200V, and the same can be achieved by the lines L2, L4 and Ln. Voltage is 200V
A three-phase distribution line can be constructed. Therefore, using these three-phase distribution lines, the distribution transformer Ts
It becomes possible to supply power to the load between the power receiving transformer Tr and the power receiving transformer Tr.

In the embodiment shown in FIG. 3, the configuration of the power receiving transformer Tr is the same as that in the embodiment shown in FIG.

4 and 5 show a further embodiment of the present invention, in which a distribution transformer
Tap A from the position that divides the number of turns of the winding portion on both sides of the neutral point N1 of the secondary winding Ta2 of Ts into two.
1 and A2 are pulled out, and taps B1 and B2 are pulled out from positions that divide the number of turns of the winding portions on both sides of the neutral point N2 of the secondary winding Tb2 into two. In this example, lines L A1 and L A2 are connected to taps _A1 and _A2 , respectively, and lines L B1 and L B2 are connected to taps _B1 and _B2 , respectively. In addition, the neutral points of secondary windings Ta2 and Tb2 are commonly connected and grounded, and the line is connected to the connection point of both neutral points.
Ln is connected. The configuration on the power receiving transformer side is the same as the embodiment shown in FIG.

In this embodiment, two of the distribution transformers Ts
If the next-side voltage is 400V, the voltage between the line Ln connected to the neutral point and each of the lines L _A1 , L _A2 , L _B1 , L _B2 is 100 V, so 100 V is applied near the distribution transformer Ts. Line Ln and line when there is a load of
Any one of L _A1 , L _A2 , L _B1 , and L _B2 can be used to supply power to the load.

In the above explanation, the case where the power is distributed by stepping down the voltage from 6600V to 400V is taken as an example, but the present invention is not limited to these voltages, and the present invention is not limited to these voltages. It can be applied to lines of a given distribution voltage that require grounding at a positive point.

[Effects of the Invention] As described above, according to the present invention, a power distribution system in which the neutral point can be grounded on the secondary side by combining two single-phase transformers for single-phase three-wire power distribution having the same specifications is achieved. A power receiving transformer can be constructed using two single-phase transformers having the same specifications. Therefore, there is no need to prepare a special three-phase transformer with a star-connected secondary winding, and it is possible to perform neutral point grounding type power distribution that complies with technical standards without increasing equipment costs. There are advantages.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing the overall configuration of an embodiment of the present invention, FIG. 2 is a connection diagram showing the connection between the transformer winding and the line in the embodiment of FIG. 1, and FIGS. 4 is a system diagram showing the main parts of other different embodiments of the present invention, FIG. 5 is a connection diagram showing the connection between the transformer winding and the line in the embodiment of FIG. 4, and FIG. FIG. 1 is a system diagram showing an example of a conventional power distribution circuit. Ts...Distribution transformer, Ta...Distribution single-phase transformer, Ta1...Primary winding, Ta2...Secondary winding,
Tb...Single-phase transformer for power distribution, Tb1...Primary winding,
Tb2...Secondary winding, Tr...Power receiving transformer, Tc...
...Single-phase transformer for power reception, Tc1...Primary winding, Tc2
...Secondary winding, Td...Single-phase transformer for receiving power, Td1
...Primary winding, Td2...Secondary winding, Lsu~Lsw...
...Power supply side distribution line, L1~L4...Line, Lru~
Lrw...Load side distribution line.

Claims (1)

[Scope of Claims] 1. A primary winding of two single-phase distribution transformers comprising two single-phase distribution transformers each having a primary winding and a secondary winding from which a neutral tap is drawn out. It is equipped with a distribution transformer formed by V-connecting lines, and two receiving single-phase transformers having a primary winding and a secondary winding, and the secondary windings of both receiving single-phase transformers are a V-connected primary winding of the distribution transformer is connected to a three-phase distribution line on the power supply side, and two secondary windings of the distribution transformer are connected to each other. are respectively connected to different primary windings of the power receiving transformer via lines, and the neutral point taps of the two secondary windings of the distribution transformer are grounded, and the V-connection of the power receiving transformer is connected to the ground. 3, characterized in that the secondary winding is connected to the load-side three-phase distribution line.
phase distribution circuit. 2. The three-phase power distribution circuit according to claim 1, wherein a line is connected to the grounded neutral point taps of both secondary windings of the power distribution transformer. 3. The three-phase power distribution circuit according to claim 1, wherein taps are further drawn out from both sides of the neutral point tap of each secondary winding of the power distribution transformer.