Pipeline systems and technologies

Inducted current protection device of AC impact

Electrical transmission line (HVTL) has a hazardous impact on a steel pipe, located nearby:

  • if a pipeline goes in parallel with HVTL;
  • at intersection areas of pipelines and HVTL;
  • at convergence and removal areas of pipelines and HVTL.

A hazardous impact of a high-voltage power line on a pipeline is expressed as follow:

1. As a result of HVTL AC electromagnetic field, the induced electrical voltages and currents occur in the pipeline which can lead to:

  • threat to the workers safety;
  • electrolytic corrosion from AC;
  • damage of electrical equipment connected to the pipeline.

2. In case of HVTL damage the pipeline may be directly under voltage of several thousand volts.

3. HVTL are potentially dangerous in terms of atmospheric overvoltage (lightning) which requires the use of appropriate pipeline protection devices (lightning protection).

To reduce the impact of electrical transmission line a device for AC pipeline protection (ICPD) is used.

Functions

Inducted current protection device is a part of pipeline cathodic protection system  (CP) against corrosion and performs the following functions:

  • drains the AC induced by HVTL through grounding device;
  • prevents the CP potential leakage;
  • allows to measure drained AC through the built-in ICPD transformer;
  • equipped with lightning protection device.

Technical data:

General:

Operating temperature limits:

— “Md” climatic version

— “Cl” climatic version 

 

from – 40°C to + 60°C

from – 60°C to + 60°C

Maximum DC leakage current, if Umax= 3,5 V [=], IL [=], mA ≤ 1
AC drained unit:
Nominal drained current 50 Hz, IA [~], A (depending on ICPD version)  40 or 80
Maximum drained current during 1 sec/50Hz, Imax [~], A  400
Grounding device:
Grounding conductor cross-section, mm2 35
Length of a vertical ground conductor section (bar), m 1,5
Diameter of a vertical ground conductor, mm 16
Length of a horizontal ground conductor section (bar), m 2,0
Width of a horizontal ground conductor, mm 40
Thickness of a horizontal ground conductor, mm 4