JPH0641329U - Bus duct - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a bus duct capable of suppressing overheating of a neutral conductor or a medium-phase conductor and increasing capacity. [Structure] In a bus duct 1 in which a plurality of conductors 3, 4, 5 and 6 forming a voltage line and a neutral line are accommodated in a duct 2, the neutral line conductor 6 is formed from the voltage line conductors 3, 4, and 5. Is also made of a conductive material having high conductivity.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a bus duct.

[0002]

[Prior art]

 Bus ducts are used for indoor and outdoor wiring that connects between switchboards or between switchboards and main circuits (such as transformers). There are two types of bus ducts: an insulated bus duct in which a conductor (bus bar) is covered with an insulator and housed in a metal duct (housing), and an air-insulated bus duct in which the bus bar is housed in a housing via an insulator. These bus ducts are used in various types of wiring systems, and are also used in distribution lines having neutral wires. A conventional three-phase four-wire insulated bus duct will be described as a conventional bus duct. A conventional 3-phase 4-wire bus duct has, for example, the structure shown in FIG. That is, the bus duct 1 is configured by closely fitting the four conductors 3, 4, 5 and 6 having the insulation coating 7 including the neutral conductor 6 in the metal duct 2 having a rectangular cross section. ing. The conductors 3, 4, 5, 6 are all made of aluminum for weight saving. Further, the neutral conductor 6 is arranged so as to be closest to the surface of the duct 2 in order to improve heat dissipation.

[0003]

[Problems to be solved by the device]

 By the way, recently, a device using a semiconductor switching element has a large capacity, and a harmonic component has often entered a wiring path. For this reason, if the number of harmonic components increases, in the case of a bus duct with a three-phase four-wire type and a neutral conductor as described above, only the neutral conductor will overheat abnormally. , A method of increasing the conductivity by changing all conductor materials from aluminum to copper has been adopted. However, the use of such means causes the following problems. Immediately: 1) Increasing the capacity of the bus duct increases cost, space, and weight. 2) When the conductor material is changed from aluminum to copper, the cost and weight increase.

[0004]

[Means for Solving the Problems]

 The present invention provides a bus duct that solves the above problems. In a bus duct in which a plurality of conductors are accommodated in a duct, some conductors of the plurality of conductors have higher conductivity than other conductors. It is characterized by increasing.

[0005]

[Action]

 As described above, if a part of the conductors is made of a conductive material having a higher conductivity than the other conductors, in the case of the three-phase four-wire system, the conductive material having a high conductivity is used. By using it for the neutral conductor, the capacity of the neutral conductor can be made relatively larger than that of the voltage conductor, and it is possible to prevent abnormal heating of the neutral conductor without increasing the overall capacity. .

[0006]

【Example】

 Hereinafter, the present invention will be described in detail based on embodiments with reference to the drawings. FIG. 1 is a perspective sectional view of a bus duct used for explaining the conventional technique. In the bus duct 1 of this embodiment, the voltage line conductors 3, 4, 5 are made of aluminum, the neutral line conductor 6 is made of copper, and all the conductors 3, 4, 5, 6 have the same size. There is. These conductors 3, 4, 5 and 6 are provided with the insulating coating 7 as in the conventional case, and are tightly accommodated in the metal duct 2. The neutral conductor 6 is arranged closest to the surface of the duct 2 in order to improve heat dissipation. Since the electrical conductivity of copper is about 1.6 times that of aluminum, in this bus duct 1, the neutral conductor 6 has about 1.6 times the capacity of the voltage conductors 3, 4, and 5. become. Therefore, the bus duct 1 has a capacitance approximately equivalent to the case where all the conductors 3, 4, 5, 6 are made of aluminum and the cross-sectional area is increased to about 1.6 times. Here, the approximate meaning is that there is a skin effect due to AC, but the effect of this effect is small and can be relatively ignored. It should be noted that the above embodiment is for a three-phase, four-wire type insulated bus duct, but it goes without saying that the present invention can be applied to a three-wire type and also an air-insulated bus duct. In the case of the 3-wire type, increasing the conductivity of the medium-phase conductor has the advantage that the impedance of each phase can be reduced and the temperature rise of the medium-phase conductor can be suppressed, so that the overall temperature rise can be reduced. .

[0007]

[Effect of device]

 As described above, according to the present invention, in a bus duct in which a plurality of conductors are housed in a duct, some of the plurality of conductors have higher conductivity than other conductors. , It is possible to increase the conductivity of neutral conductors and medium-phase conductors to prevent abnormal overheating of these conductors, so there is an excellent effect that the capacity can be increased in the same scale as conventional ones. .

[Brief description of drawings]

FIG. 1 is a perspective sectional view of a bus duct.

[Explanation of symbols]

 1 Bus duct 2 Duct 3, 4, 5, 6 Conductor 7 Insulation coating

Claims (1)

[Scope of utility model registration request] 1. A bus duct in which a plurality of conductors are accommodated in the duct, wherein some of the plurality of conductors have higher conductivity than other conductors.