JPH07264777A - Transformation panel board - Google Patents

Abstract

PURPOSE:To enable effective power transmission and distribution by stepping down voltage higher than the voltage of commercial power to the voltage of commercial power by a transformer and branching the stepped-down power to a plurality of load having different rated voltage. CONSTITUTION:A transformation panel board 20 is supplied with voltage of 240V/415V by trunk cables 40 by three-phase four-wire leading from a transformation facility, either phase of an N phase and R, S, T is connected to a breaker 24, and the primary side of a transformer 26 is supplied with voltage of 240V. The transformer 26 steps down voltage of 240V, and simultaneously outputs voltage of 200V from a tap T2 and voltage of 100V from a tap T1. Consequently, each of AC power of 200V for a lamp facility between a breaker 30 and a neutral terminal 32 and AC power of 100V for one between a breaker 28 and the neutral terminal 32 is obtained. Accordingly, a voltage drop and power loss in a transmission line up to the panel board 20 are reduced, thus enabling effective power transmission and distribution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer distribution board, and more particularly to a transformer distribution board having a transforming function.

[0002]

2. Description of the Related Art Generally, 100V / 200V commercial power is adopted in a low voltage distribution system, but this 100V / 200V distribution has a large voltage drop and power loss. The short distance that can supply electricity requires many electric poles and transformers. on the other hand,
For urban power distribution where it is difficult to construct overhead power lines, it has been considered and implemented to install power distribution equipment in the ground, but for this purpose, it is necessary to increase the power supply distance.
It is desired to employ a relatively high voltage such as 240V / 415V in the low voltage distribution system.

However, 100V which is currently popular
Electric power supply to a load facility of / 200V is indispensable now and in the future, and this is a factor that prevents urban distribution from becoming 415V.

The present invention has been made in response to the above-mentioned demand, and provides a transformer distribution board which reduces voltage drop and power loss in a transmission line up to a distribution board and enables effective power transmission and distribution. The purpose is to do.

[0005]

In order to achieve the above object, a transformer distribution board according to the invention of claim 1 is connected to a main line for transmitting electric power having a voltage higher than that of commercial electric power and the electric power transmitted. It has a built-in transformer for stepping down the voltage of commercial power to a voltage of commercial power and a branching part for branching the power stepped down by the transformer into a plurality of loads having different rated voltages.

The invention of claim 2 provides the transformer of claim 1
It is an autotransformer. According to a third aspect of the present invention, the transformer of the first aspect is provided with a single winding having a plurality of taps, both ends of which are connected to the main line, and each of the taps outputs a different voltage at the same time. It is a winding transformer.

The invention according to claim 4 is provided with a single winding having a plurality of taps, both ends of which are connected to the primary side power supply, and a load having a different rated voltage is connected to each of the taps. In a transformer distribution board equipped with an autotransformer, a specified current was applied between the primary side power supply and the tap side end to which the load with the maximum rated voltage of the single winding is connected. A first contact that sometimes performs a breaking operation is provided, and a load having a minimum rated voltage is provided between the primary side power supply and an end portion on a tap side to which a load having a minimum rated voltage of a single winding is connected. A second contact is provided in parallel and in series with a single winding so as to perform a breaking operation when a current smaller than the predetermined current is applied.

[0008]

According to the invention of claim 1, a transformer connected to a main line for transmitting electric power having a voltage higher than that of the commercial electric power and having a built-in transformer for stepping down the transmitted electric power to the voltage of the commercial electric power. Then, the electric power stepped down by the transformer at the branch portion is branched into a plurality of loads having different rated voltages. According to the invention of claim 1, since it is possible to transmit electric power having a voltage higher than the voltage of the commercial power to the position of the transformer distribution board, the voltage drop and the power loss in the main line connected to the transformer distribution board are reduced. can do. Since this transformer distribution board is usually provided for each room in a single-family house or building, it is possible to reduce the voltage drop and power loss to each room in a single-family house or building,
This makes it possible to expand the service range of distribution facilities and reduce the amount of electric wire materials.

When a transformer is built in the transformer distribution board, the usual insulating transformer is large, and if it is built in the transformer distribution board, the transformer distribution board itself becomes large, which is not preferable.
On the other hand, an autotransformer (autotransformer) has a structure in which the primary winding and the secondary winding share a part, and compared with a normal two-winding transformer, the amount of copper and iron Since it has the advantage of saving the amount and making it smaller than a normal transformer,
Suitable for being built into a transformer distribution board. Further, the size of this autotransformer is determined by its own capacity, a large output can be obtained with a small self capacity, and it is advantageous that the transformation ratio is close to 1. Therefore, in the invention of claim 2, the autotransformer is used as a transformer to be built in the transformer distribution board, and in the invention of claim 3, in order to distribute to a plurality of loads having different rated voltages, , A single winding has a plurality of taps, and different voltages are simultaneously output from the taps.

However, the autotransformer is characterized in that it can be operated with a smaller current by combining the primary and secondary currents and can save materials, so in the autotransformer having a plurality of taps, If loads are separately connected to the taps, the current value will differ depending on the location of the winding. Therefore, it is necessary to consider protection of the entire winding.

Therefore, according to the invention of claim 4, the first contact is provided between the primary side power source and the end portion on the tap side to which the load having the maximum rated voltage is connected, and the primary side power source and the single contact are provided. A second contact, which is cut off by a current value smaller than that of the first contact, is provided between the winding and the end on the tap side to which the load having the minimum rated voltage is connected.

Since the currents flowing through the loads having different rated voltages pass through the first contact, it is possible to prevent the total current branched from the transformer distribution board by the first contact from exceeding a predetermined value. it can. Also, when many loads with the minimum rated voltage are connected to the autotransformer, these loads of the windings are connected in parallel even if the current value flowing through the first contact is small because the rated voltage is low. A large current will flow in the part, but when a predetermined current flows in a part of the winding by connecting the second contact in series to the winding in which this minimum load is connected in parallel. In addition, the second contact is made to perform the breaking operation even if the first contact is not made to the breaking operation. As a result, the autotransformer can be protected even when power is simultaneously supplied to a plurality of loads having different rated voltages.

Thus, according to the invention of claim 4, electric power can be supplied to loads having different rated voltages while protecting a single autotransformer, and the autotransformer can be efficiently used to transform a transformer. It is possible to suppress the size increase of the electric panel itself.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. As shown in FIG. 1, the CVQ is installed in the substation equipment 2.
Transformer distribution board 20 via a main cable 40 such as a cable
Are connected.

The transformer distribution board 20 of this embodiment has a main terminal 22, a two-pole breaker 24, an autotransformer 26, and the like built therein. Main terminal 2 for transformer distribution board 20
2 is connected to the substation equipment 2 shown in FIG. 1 via a trunk cable 40. The primary side of the breaker 24 is connected to the main line terminal 22, and the primary side of the autotransformer 26 provided with _two taps T ₁ and T ₂ is connected to the secondary side of the breaker 24.

The autotransformer 26 and the main line terminal 2
2, a neutral terminal 32 is connected, the tap T ₁ of the autotransformer 26 is connected to a breaker 28, and the tap T ₂ of the transformer 26 is connected to a breaker 30. A low voltage, which is used as commercial power, is applied to each load facility by a wiring (not shown) connected between any of the breakers 28 and 30 and the neutral terminal 32.

In the transformer distribution board 20 shown in this embodiment, the voltage of 240V / 415V is supplied from the transformer equipment by the three-phase four-wire drawing by the main cable 40, and the N-phase and R-
Either phase of S or T (N in the transformer distribution board 20 of the present embodiment)
Phase and R phase, the transformer distribution board 20A has N phase and S phase, and the transformer distribution board 20B has N phase and T phase) are connected to the breaker 24 to supply a voltage of 240 V to the primary side of the transformer 26. ing.
The transformer 26 steps down the voltage of 240V supplied to the primary side, taps T ₂ to 200V, taps T ₁ to 100V.
The voltage of V is output at the same time. This allows the breaker 3
200V between 0 and neutral terminal 32, 10 between breaker 28 and neutral terminal 32
AC power of 0V for each lighting equipment can be obtained.

A trunk cable 40A, which is connected to another transformer distribution board 20A, is connected to the trunk terminal 22. In this embodiment, a relatively high 240V / 415V is used.
Electricity is supplied to a plurality of transformer distribution boards at a high voltage with high efficiency. The transformer distribution board 20A is connected to the transformer distribution board 20B via a trunk cable 40B. The breaking capacity of the breaker 24, the capacity of the transformer 26, etc. may be set according to the capacity of load equipment connected to the breakers 28, 30 and the neutral terminal 32.

Next, the autotransformer of the transformer distribution board of this embodiment will be described in more detail with reference to FIG. This autotransformer comprises a single winding 10 provided with _two taps T ₁ , T ₂ . The taps are not interchangeable and are configured to use multiple taps T ₁ , T ₂ at the same time. Rated voltage is connected to one end of the load 16 of the V ₁ was the tap T _1, rated voltage V ₂ to the tap T ₂ (>
One end of the load 18 of V ₁ ) is connected. Note that FIG.
Then, the breakers 28, 30 and the like are not shown. The other ends of the loads 16 and 18 are connected to the primary power supply.

The autotransformer has two contacts 12 which are cut off when a predetermined current having a different value is applied.
A two-pole breaker 24 provided with 14, that is, a two-pole breaker having a different rated current for each pole is connected. That is,
One end of the winding 10 is connected to one end of the primary side power supply through a first contact 12 of a two-pole breaker that is cut off when a first predetermined current is applied. Further, the other end of the winding 10 is cut off when a second predetermined current smaller than the first predetermined current is applied and is in parallel with the load 16 and
Is connected to the other end of the primary-side power supply via a second contact 14 that is connected in series.

According to this embodiment, the first contact 12 has a first
Is applied to the first contact 12 or the second contact 14 is applied with a second current, the first contact 12 and the second contact 1
4 are cut off simultaneously, the load and the winding of the autotransformer are protected from overcurrent.

In the above embodiment, in order to reduce the size of the distribution board and save resources, an example in which a single two-pole breaker with a different rated current for each pole is used to simultaneously shut off has been described. Separate breakers may be connected instead of each of the first contact and the second contact.

Next, the primary side power supply voltage 240 [V], the secondary voltage 200 [V] / 100 [V], and the self capacity 1 [KV
Consider the A] autotransformer.

In FIG. 3, the primary side power supply voltage is V ₀ , the total load capacity is L, the ratio of the load 16 having a rated voltage V ₁ to the total load capacity L is r (where 0 ≦ r ≦ 1), the current flowing through the first contact 12 I _0, the current flowing through the load 16 I
₁ , the current flowing through the load 18 is I ₂ , the tap T of the winding 10 is
Current flowing between ₁ and the second contact 14 (coil A),
That is, the current flowing through the second contact 14 is I _A , the winding 10
Tap T _1, between T ₂ the current flowing through the (coil B) I _B of
Then, the following relationships exist among r, I ₀ , I _A , I _B , L, and the like. _{L = V 0 I 0 rL =} I 1 V 1 (1-r) L = I 2 V 2 I B = I 2 -I 0 I A = I B + I 1 = I 1 + I 2 -I 0 ··· ( 1) From the above formula (1), I _A and I _B are as follows. _{I B = (V 0 -V 2} -rV 0) I 0 / V 2 ··· (2) I A = {V 1 (V 0 -V 2) + rV 0 (V 2 -V 1)} I 0 / V ₁ V ₂ (3) Here, the self-capacitance of the winding 10 is S, and the self-capacitance S is RS with respect to the load 16 (where 0 ≦ R ≦ 1) and the load 18
With respect to (1−R) S, the distribution is as follows. _{RS = rL (V 0 -V 1} ) / V 0 ··· (4) (1-R) S = (1-r) L (V 0 -V 2) / V 0 ··· (5) Also, From the above equations (4) and (5), S and R can be expressed as follows. S = L {V ₀ −V ₂ + r (V ₂ −V ₁ )} / V ₀ L = V ₀ S / {V ₀ −V ₂ + r (V ₂ −V ₁ )} Therefore, each current I ₀ , I _B, I _a is as follows. I ₀ = L / V ₀ = S / {V ₀ −V ₂ + r (V ₂ −
_{V 1)} I B = (} V 0 -V 2 -rV 0) S / [V ₂ {V ₀ -V <sub>2
+ R (V 2 -V 1)</sub> } ] _{I A = {V 1 (V} 0 -V 2) + rV 0 (V 2 -V 1)}
S / [V ₁ V ₂ {V ₀ −V ₂ + r (V ₂ −V ₁ )}] Here, the voltage V ₀ of the primary power supply is 240 [V], the load 1
The rated voltage V _{1 of} 6 is 100 [V], the rated voltage V ₂ of the load 18 is 200 [V], and the self-capacitance S of the autotransformer is 100 [V].
Assuming 0 [VA], I ₀ , I _B , I _A and L are as follows. _{I 0 = 50 / (2 +} 5r) [A] _{I B = (10-60r) / (} 2 + 5r) [A] _{I A = (10 + 60r)} / (2 + 5r) [A] L = 12 / (2 + 5r ) [KVA] The , 0 ≦ r ≦ 1, changes in I ₀ , I _A , I _B , and L are shown in Table 1.

[0025]

[Table 1]

As can be seen from Table 1, when the self-capacitance S is used to the maximum, I ₀ is 25 [A] at the maximum (all 2
00 [V] load), I _A is 10 [A] at maximum
(When all are set to 100 [V] load), I _B is 7.
It becomes 1 [A] (when all loads are 100 [V]).

Therefore, the allowable currents of the coils A, B and C are as follows: Coil A ... 10 [A] Coil B ... 7.1 [A] Coil C ... 25 [A] ] Becomes The coil C is the first contact 12 of the winding 10.
And the tap T ₂ .

From the above, the first predetermined current (rated current) of the first contact 12 for protecting the coil C of the autotransformer may be set to 25 [A] or less. Further, as can be understood from Table 1, only one of the currents I _A and I _B does not become an overcurrent, and therefore the second predetermined current of the second contact 14 for protecting the coils A and B is used. (Rated current) is 1
It may be set to 0 [A] or less.

As described above, the transformer distribution board 20 of the present embodiment.
Has a single autotransformer with a plurality of taps, it is possible to output a plurality of voltages at the same time.
Also, because the single-pole transformer with a different rated current for each pole is used to protect the autotransformer, the autotransformer can be made even smaller, and the distribution board can be made smaller and lighter. Can be realized.

In this embodiment, the first contact 12 and the second contact 14 having different breaking operation capacities are the same breaker 2.
However, the present invention is not limited to this, and the first contact 12 and the second contact 14 may be configured by different breakers.

Further, in the above-mentioned transformer distribution board 20, an example of using the autotransformer has been described, but a normal transformer may be used. As a result, the transmission voltage to the transformer distribution board can be increased regardless of the rated voltage of the load, and the efficiency of power transmission to the transformer distribution board can be improved and the material cost of the transmission equipment can be reduced.

Further, breakers for protecting the autotransformer may be separately provided for each pole.

[0033]

As described above, according to the present invention, since the transformer is built in the distribution board, it is possible to transmit at a low voltage higher than the voltage used for a general load, thereby improving the transmission efficiency. In addition, it is possible to reduce the material cost of the power transmission line. Further, by using the autotransformer, it is possible to reduce the size and weight of the transformer distribution board.

In addition to this, in the invention of claim 4, since the autotransformer is provided with the first contact and the second contact, when the autotransformer has a small self-capacitance, Also in this case, an excellent effect that not only the overcurrent of the load but also the autotransformer itself can be protected is obtained.

[Brief description of drawings]

FIG. 1 is a wiring diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing an embodiment of the present invention.

FIG. 3 is a circuit diagram showing an autotransformer according to an embodiment of the present invention.

[Explanation of symbols]

 10 Winding 12 First contact 14 Second contact

Claims (4)

[Claims] 1. A transformer connected to a main line for transmitting electric power having a voltage higher than that of commercial electric power and for stepping down the transmitted electric power to the voltage of commercial electric power, and the electric power stepped down by the transformer at a rated voltage. A transformer distribution board that has a built-in branching section that branches into multiple different loads. 2. The transformer distribution board according to claim 1, wherein the transformer is an autotransformer. 3. The transformer is a single-winding transformer having a plurality of taps and having a single winding whose both ends are connected to the main line, and simultaneously outputting different voltages from each of the taps. The transformer distribution board according to claim 1. 4. An autotransformer having a plurality of taps and having a single winding whose both ends are connected to a primary power source, and a load having a different rated voltage being connected to each of the taps. In a transformer distribution board, the first power supply cuts off when a predetermined current is applied between the primary side power supply and the end on the tap side to which the load with the maximum rated voltage of the single winding is connected. Is provided between the primary side power supply and the end of the single winding connected to the tap side to which the minimum rated voltage load is connected, in parallel with the minimum rated voltage load and in a single winding. A transformer distribution board, characterized in that a second contact is provided in series with the wire, the second contact being cut off when a current smaller than the predetermined current is applied.