For the company, ENGIE Lab Laborelec, we at POWERSYS performed an electromagnetic interference study, in order to evaluate the influences of three transmission lines (220 kV and 70 kV) on a buried gas pipeline. This is according to the standards ITU-T K33 and IEC 60479-1.
Different kinds of installations (metallic pipelines, telecommunication systems, power systems) can be subject to induced voltage and current in the vicinity of electrical systems. The operating conditions (normal steady-state or fault) of the disturbing systems and the position (overhead or buried) of each installation are the origin of inductive, capacitive, or conductive coupling. Electromagnetic interferences studies can be performed to investigate these effects.
Our POWERSYS engineering team used EMTP-RV and its third-party software, Crinoline, to realize this study. Geographic positions of different systems are represented in a Crinoline Interface using GPS coordinates. Electric models, like the upstream network or the fault, are represented in EMTP-RV interface. Induced voltages in the buried pipeline are calculated in steady-state and fault conditions.
Induced voltage (V) all along the pipeline
POWERSYS also proposed a solution to mitigate the induced voltage when it exceeds the specified levels of voltage as defined in the standards. Grounding electrodes are installed in different locations along the buried pipeline in order to reduce the induced voltage and keep them under the allowed levels.