Simplified Algorithm for BFOR and Tower Grounding Performances in High Voltage Lines Engineering

This paper illustrates how a simplified methodology has been derived from the analytic procedure in determining back-flashover rate (BFOR) and tower grounding resistance performances of high voltage (HV) overhead transmission lines (OHTLs) design. The proposed methodology is suitable for application at design stage whenever the analytic, full procedure envisaged in CIGRÉ Technical Brochure 63 cannot be implemented due to unavailable data – pretty frequent at the design stage – or its inherent complexity. A simplified algorithm can be used for design purposes without detrimental impact on the level of confidence of the expected results. The proposed simplified procedure has been validated by comparing computed results with records of a real case of application, where operating data were available, here reported. The paper also presents the result of a case of application to recently designed OHTLs in Tanzania Mainland.