Lightning Protection of HV & MV Systems and Grounding Concerns
Expected Outcome: At the end of this course the participant will be able to understand the causes of transient related failures in transmission and distribution systems, to work out required spacing and insulation coordination parameters to protect power systems, to guide the technical staff for up-keeping proper maintenance record and identify hot-locations and address critical issues of earthing.
Topic 1
Lightning Threats of HV and MV systems
Description
Calculation of strike probability to transmission lines, Traveling waves in transmission and distribution Lines, Cases of lightning accidents and damage in transmission and distribution systems, Threat analysis, and risk assessment.
Topic 2
Protection scenario of transmission lines
Description
Surge impedance and protection techniques of towers, poles and mounted devices, Shielding by OHGW and other grounding routes, Grounding technologies and materials, Lightning and transient performance of single and combined insulation materials, Insulation coordination, Critical flashover voltage and voltage-time characteristics, the technology of surge suppressors and lightning arresters, application of arresters in power transmission lines.
Topic 3
Protection techniques of MV distribution systems
Description
Design and selection criteria of surge protectors for distribution systems, spark over voltage of arresters, Insulation coordination; coupling models of lightning into transmission lines, design concerns of lighting and transient protection systems for grid substations, generator housings etc., protection of distribution transformers, grounding concerns of LV Transformers and improvement, International guidelines and codes of maintenance.
Topic 4
Specific Grounding Issues
Description
Measurement and analysis of ground resistance and soil/ground resistivity and its’ seasonal/regional variation, designing of electrode configurations for extremely high resistive ground, temporal impedance behavior of earth electrodes under lightning transients, long term characteristics of backfill materials, and soil treatment agents used for earthing improvement, design criteria and critical parameters of earthing grid substations, switchyards etc. (large scale earthing networks), Maintenance and inspection of large scale earthing systems, Integration and coordination of LP, LV and signal earthing systems at a given installation, prevention of material erosion in acidic and high salinity soil conditions, transient couplers, Measurements and testing as per IEEE Green Book and IEEE Emerald Book.
Topic 5
Discussion and tutorials
Description
Q & A on specific earthing issues, questionnaire on addressing abnormal cases of achieving & maintaining earthing systems.