DC (Stray Current) Interference

DC Stray Current Interference: D.C. systems may cause currents to flow in the earth or any other electrolyte, whether intentional or unintentional. A few examples of these systems include: d.c. traction systems, HVDC systems, PV power systems, geomagnetic interference, etc. When for personnel safety, earthing or equipotential bonding is necessary, special care shall be taken in order to avoid stray currents that may be leading to accelerated corrosion of supporting and third-party metallic infrastructure. Stray current corrosion refers to corrosion damage to metallic infrastructure resulting from DC flow other than in the intended circuit.
Technical Consultancy:

  • Holistic Modelling Approach using a mix of methods and software to model the stray current interactions of d.c. power systems under both static & dynamic operation. Through a complete modelling suite, we provide the following engineering services:
    • Impact Analysis on Supporting Infrastructure and third-party Assets
    • Design Review (including C.P., soil models, earthing systems, stray current collection systems)
    • Ensure Compliance with Applicable Standards & Regulations
List of Completed Projects:

  • Stray Current Control and Design Assessment for Thessaloniki DC Metro System, ELEMKO, April 2013
  • Comparison of the steel and concrete sleeper stray current performance for a tram train project between Sheffield and Rotherham”, Intertek UK and UK Network Rail, May 2015.
  • Dynamic Modelling for Diode-Bonded DC Traction Systems- Validation of Manchester’s City Centre Single Tram Test”, Intertek UK, October 2016.
List of Relevant Peer-Reviewed Publications:

  • A. Dimitriou and C.A. Charalambous, “DC Interference Modelling for Assessing the Impact of Sustained DC Faults of Grounded Photovoltaic Systems on Third-Party Infrastructure”, IEEE Transactions on Industrial Electronics, DOI (identifier) 10.1109/TIE.2018.2844841, May 2018.
  • A. Dimitriou, D. Buxton and C.A. Charalambous, “Stray Current Corrosion Blind Spots Inherent to PV Systems Fault Detection Mechanisms: Elaboration of a Novel Concept”, IEEE Transactions on Power Delivery vol. 33, no. 1, pp. 3-11, Feb. 2018, 10.1109/TPWRD.2016.2538789.
  • C.A. Charalambous “Comprehensive Modelling to Allow Informed Calculation of DC Traction Systems’ Stray Current Levels” IEEE Transactions on Vehicular Technology, Volume 66, Issue 11, Pages: 9667-9677, Nov. 2017, 10.1109/TVT.2017.2748988.
  • C.A. Charalambous, P. Aylott and D. Buxton, “Stray Current Calculation and Monitoring in DC Mass-Transit Systems: Interpreting Calculations for Real-Life Conditions and Determining Appropriate Safety Margins“, in IEEE Vehicular Technology Magazine, vol. 11, no. 2, pp. 24-31, June 2016. doi: 10.1109/MVT.2015.2477419
  •  C.A. Charalambous, A. Demetriou and N. D. Kokkinos, “Impact of Photovoltaic-Oriented DC Stray Current Corrosion on Large-Scale Solar Farms’ Grounding and Third-Party Infrastructure: Modeling and Assessment“, in IEEE Transactions on Industry Applications, vol. 51, no. 6, pp. 5421-5430, Nov.-Dec. 2015.
  • C.A. Charalambous and Aylott, P., “Dynamic Stray Current Evaluations on Cut-and-Cover Sections of DC Metro Systems”, Vehicular Technology, IEEE Transactions on, vol.63, no.8, pp.3530, 3538, Oct. 2014.
  • Charalambous, C.A.; Cotton, I.; Aylott, P., “Modeling for Preliminary Stray Current Design Assessments: The Effect of Cross Track Regeneration Supply“, Power Delivery, IEEE Transactions on, vol.28, no.3, pp.1899, 1908, July 2013.
  • Charalambous, C.A.; Cotton, I.; Aylott, P.; Kokkinos, N.D., “A Holistic Stray Current Assessment of Bored Tunnel Sections of DC Transit Systems,” Power Delivery, IEEE Transactions on , vol.28, no.2, pp.1048,1056, April 2013.
  • C.A. Charalambous, I. Cotton, P. Aylott, ‘’A simulation tool to predict the impact of soil topologies on coupling between a light rail system and buried third party infrastructure’’ , Vehicular Technology, IEEE Transactions on, Vol. 57, No. 3, pages: 1404-1416, May 2008.
  • C.A .Charalambous, I. Cotton, ‘‘Influence of soil structures on corrosion performance of floating DC Transit Systems’’, IET Electric Power Applications (formerly IEE Proceedings), Vol. 1, Issue 1, pages: 9-16, January 2007.
  • I. Cotton, C.A. Charalambous, P. Ernst, P. Aylott, ‘‘Stray Current Control in DC Mass Transit Systems’’, IEEE Transactions on Vehicular Technology, Vol. 54, No. 2, pages: 722 – 730, March 2005.