JPS5910479Y2 - Induced voltage reduction device for buried pipes installed under power transmission lines - Google Patents

Description

[Detailed description of the invention] Buried pipes are generally used as a means of transporting gas, oil, water, etc.

Buried pipes are coated on the outside for corrosion protection purposes, and in recent years, as coating materials have improved, pipes with fewer pinholes and higher insulation levels have been manufactured.

Tubes buried parallel to power transmission lines are induced by alternating voltage and produce alternating voltage.

In particular, as mentioned above, when the insulation of the coating is good, a voltage of several tens of volts is generated, which can cause sparks at the end of the pipe and is dangerous to human resources.

The purpose of the present invention is to reduce this induced voltage and to protect buried pipes from corrosion.

An embodiment of the present invention will be described below with reference to FIG.

In Fig. 1, 1 is a buried pipe laid under the power transmission line;
2 is a low ground conductor that uses the foundation piles of existing structures.

In addition, as the resistance grounding conductor 2, for example, old steel material driven into the ground may be used.

A rectifying element 3 is provided between the buried pipe 1 and the low ground conductor 2, and the rectifying element 3 is connected in the forward direction from the buried pipe 1 to the low ground conductor 2, and in parallel with this rectifying element 3, the rectifying element is connected in the opposite direction to the above. 4
A series circuit consisting of the variable resistor 5 and the variable resistor 5 is connected.

Therefore, in FIG. 2, if the rectifying element 4 and the variable resistor 5 are not present, an alternating current voltage is generated between the low ground conductor 2 and the buried pipe 10, so that the alternating current is lower than the buried pipe 1. Only half a cycle flows in the direction of conductor 2.

Therefore, the buried pipe 1 is in a cathodic-protected state, but since a fairly large current generally flows, it becomes over-corrosion-protected, and the stripping effect of the AC voltage also causes a short circuit between the buried pipe 1 and the low-ground conductor 2. % of the case.

When the rectifying element 3 and the rectifying element 4 which can be adjusted in the opposite direction are connected, the ground potential of the buried pipe 1 can be selected to the most appropriate value by adjusting the reverse direction current.
The AC voltage can be reduced and the effect of cathodic protection can be obtained.

In addition, as a current adjustment circuit, rectifying element 4 in FIG.
, instead of the variable resistor 5, a thyristor is used as shown in FIG.
6 and this control circuit 7, similar effects can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, and FIG. 2 is a circuit diagram showing another embodiment of the present invention.

Claims (1)

[Scope of utility model registration request] A rectifying element is connected between the buried pipe laid under the power line and the low ground conductor, with the direction from the buried pipe forward to the low ground conductor.
A device for reducing induced voltage in a buried pipe installed under a power transmission line, in which a series circuit consisting of a rectifying element and a variable resistor connected in parallel with this rectifying element is connected in parallel with the rectifying element.