On the occasion of two incidents of buried gas pipeline perforations – on the National Natural Gas Transmission System – caused by lightning strikes that were enough to alarm the system operator (DESFA), the Operations Division/Integrity and Inspection Dept/Inspection Section of DESFA has effectively collaborated with ELEMKO SA and Power Systems Modelling (PSM) Laboratory of the University of Cyprus (UCY) to understand the impact of direct lightning strikes on its underground Gas Pipeline System. A specialized modelling study of the phenomenon has been elaborated which was validated with laboratory testing and field evidence. Of particular importance were the elucidation of the failure mechanism as well as the quantified approach on the impact severity of each of the main affecting parameters involved, leading to the development of a valuable risk assessment tool.
More specifically, the main deliverable of the study was to develop a model of the phenomenon that by selecting specific parameters helps us assess the risk at every area of the gas transmission grid. These parameters are basically: the lightning ground flash density per geographic region (we have entered into cooperation with the National Observatory of Athens to take the data along DESFA pipeline), the ageing of coating, the stratification and the electrical properties of the soil, the effect of existing earthing electrodes, the interference from adjacent electric power lines, the position and dimensions of the pipeline.
The results of this collaboration have been published in the prestigious scientific journal IEEE Transactions of Power Delivery – following a peer-reviewed process.
The archived value of this paper derives from the field experience and knowledge of DESFA and ELEMKO as well as the expertise of the UCY PSM LAB in the areas of EMI, Earthing and Corrosion. This common venture comes in response to the worldwide scientific efforts that aim to understand the mechanisms of undesirable field failures in gas transmission systems.
The know-how gained by this pioneering work can be certainly transferred to other gas systems operators.
The project was coordinated on behalf of DESFA by Dr. Nikolaos Kioupis and Mr. Theagenis Manolis, in collaboration with Dr. Nikolaos Kokkinos from ELEMKO, a specialized in lightning protection Greek company and Mr. A. Dimitriou and Associate Professor. C. A. Charalambous from the University of Cyprus.
The paper (Ch. A. Charalambous, A. Demetriou, N. Kioupis, Th. Manolis, N. Kokkinos, Wall Fusion of Buried Pipelines due to Direct Lightning Strikes: Field, Laboratory and Simulation Investigation of the Damaging Mechanism) has an early access link in the IEEE (Institute of Electrical and Electronics Engineers) website:
https://ieeexplore.ieee.org/document/8750891
