JP2006288127A - Embedded electric wire pipeline having drainage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To continuously keep the inside of a conduit tube dry even under a long-term use in pull-in facilities in private power receiving facilities, and to prevent water from staying inside the conduit tube. <P>SOLUTION: When water sealing treatment is performed to the end of the conduit tube, a triangle wedge is used for sealing reliably. A drainage tank is provided for discharging rainwater in the conduit tube. By a float in the tank, a water level can be easily determined on the ground. Air is allowed to flow in the conduit tube for drying. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

    Applicable to the technical fields of underground electrical conduit construction and maintenance inspection of electrical equipment.

In high-voltage power receiving equipment, as a facility for service lines, high-voltage cables
Work that falls from an outdoor utility pole and rises in a receiving cubicle via an underground conduit is widely implemented. Related applications include the following.
JP 2002-138450 A

A conventional lead-in buried electric line will be described with reference to FIG.
As for the construction sequence, the wiring route is excavated, and the underground conduit 7 is laid and backfilled.

Next, the high-voltage cable 6 is passed through the buried conduit and both ends of the cable are terminated.

In order to prevent rainwater intrusion, the waterproofing material 26 is used, and the seal part 17 is constructed and completed.

However, when exposed to the environment (particularly ultraviolet rays and temperature changes) for a long period of time, the seal portion 17
Will lose its water shielding function and allow rainwater to enter.
As shown in FIG. 6, in particular, when the high-voltage cable is a triplex type in which single cores are twisted together, the center A of the multi-core has nothing to stop the sealing material and is difficult to seal.

As a result, rainwater accumulates in the buried conduit 7 and becomes stagnant water 16.
FIG. 5 shows an example of a photograph of accumulated water in the conduit tube in the power receiving cubicle.
High-voltage cables are always immersed in water, triggering water tree deterioration and shortening the service life.

If the seal portion 17 is kept watertight, the water once entering the buried conduit is not preferable because it has no outlet and remains wet.

Even when the private power receiving equipment is used for a long period of time, the inside of the conduit 7 is always kept dry.

Prevent water from accumulating inside the conduit. It is also a measure that can be offered at a much lower price than large facilities such as hand holes and manholes.

In FIG. 1, the basin 16 is allowed to flow naturally into the drain tank 11 through the drain pipe 12 from the lowest position of the buried conduit 7.

Even if rainwater collected in the lower part of the water draining tank 11, the permeation hole 13 was arranged so as to discharge the rainwater as soon as possible.
However, if the groundwater level is higher than the bottom of the drain tank 11 in a low-humidity area,
The penetration hole 13 is blocked to prevent intrusion of groundwater.

A float 14 floats inside the water draining tank 11, and there is a rod 20 fixed to the float 14.
When the float 14 moves up and down due to a change in the water level, the rod 20 moves up and down according to the guide 18.

A water level display unit 15 is provided at the upper end of the rod 20, and the display unit displays a water level scale or red, yellow, and blue.
If you look at the display section, you can see the water level inside the drain tank 11 and drain it with a small pump if necessary.
The capacity of the water draining tank 11 may be calculated from the duration of rainfall and the intrusion flow rate of rainwater.

The lid 19 is for inspecting the inside of the drain tank 11 and prevents rainwater from directly entering the drain tank 11.

The guide 18 has a pipe structure and is fixed to the lid 19. It acts to keep the rod 20 vertical.

Install caps 21 at both ends of the buried conduit 7 to prevent rainwater from entering the conduit 7
Are provided with a vent hole 22 and a water drain tank 11 with a vent pipe 28 so that air can freely flow. However, consideration should be given to preventing the invasion of small animals such as snakes.

For the sealing portion 17 at the end of the conduit 7, the assembly procedure is as follows. After processing the cap 21 as shown in FIG. 7-2 and passing the single core of the cable 6, the triangular wedge 27 is changed as shown in FIG.
Then push in the seal material 17 (putty, etc.) and seal the water.
The triangular wedge 27 is tapered and is easy to push. Moreover, the protrusion 29
Is larger than the processing hole of the cap 21, the triangular wedge 27 stops and does not fall down.

The high-voltage cable is improved from a submerged state to a dry environment. It is freed from the risk of cable water tree deterioration, and high-voltage cable accidents can be reduced.

The buried conduit is desirable because the higher the vertical portion is, the more the flow of air in the conduit becomes more active and the more moisture is evaporated.

As shown in FIG. 1, if the drain tank 11 is made by processing a vinyl chloride pipe, the amount of excavation can be reduced and the construction can be made significantly cheaper than when hand holes or manholes are installed.
The conduit is a corrugated rigid polyethylene conduit (FEP) that is light and strong, and has good workability. At the time of backfilling, the drainage pipe 12 is subjected to earth pressure, so it is necessary to consider the strength of the connecting portion.

Pipeline system of the present invention Conventional pipeline system Drain tank Conduit vents and caps Condensate water photograph of the conduit (in the receiving cubicle) Conventional conduit seal Conduit seal part of the present invention

Explanation of symbols

1 electric pole 2 air top switch 3 transaction voltage / current transformer 4 lightning arrester 5 cable terminal processing section 6 CV-T cable 7 buried conduit 8 ground 9 power receiving cubicle 10 foundation 11 drain tank 12 drain pipe 13 penetration hole 14 Float 15 Water level display 16 Retained water 17 Seal 18 Guide 19 Lid 20 Rod 21 Cap 22 Air hole 23 Air flow 24 Rainwater flow 25 Permeated water flow 26 Pipe port waterproofing material (made of rubber)
27 Triangular wedge 28 Vent pipe 29 Projection

Claims (4)

A drain pipe and drain tank were installed at the bottom of the buried conduit.
Electric conduit A drainage tank with vents and caps at both ends of the buried conduit
Has a ventilation pipe in the lid, and air freely circulates in the conduit
Electric conduit. The water drain tank according to claim 1 is equipped with a float, and the water level of the tank
Drain tank that can be easily judged on the ground. Using a triangular wedge for the water shielding treatment of the cap of claim 2
Conduit cap that can reliably block water.