Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
Step potential and touch potential is associated with
High voltage transmission
Earthing of the substation
Voltage rise in the substation
Communication systems
Earthing of the substation
Step and touch potentials are hazardous voltages that occur during a ground fault in a substation. They are directly associated with the design and effectiveness of the substation earthing grid, which aims to minimize potential differences between points on the ground surface.
Step and touch potentials are hazardous voltages that occur during a ground fault in a substation. They are directly associated with the design and effectiveness of the substation earthing grid, which aims to minimize potential differences between points on the ground surface.
VstepтАЛ=IfтАЛ├Ч(RsтАЛ+2╧Б) тАФ Potential difference across a 1m span
VtouchтАЛ=IfтАЛ├Ч(RsтАЛ+0.5╧Б) тАФ Potential difference between structure and earth
When a fault current flows into the ground through an earthing electrode, it creates a potential gradient field around the substation. Step potential is the potential difference between two points on the ground separated by one meter, whereas touch potential is the potential difference between a grounded metal structure and the ground at a distance of one meter.
Step potential is critical for preventing electric shock to persons walking near the substation during a fault.
Touch potential is critical for protecting personnel touching metallic equipment frames during a fault.
Substation earthing grids are designed to keep these potentials within safe limits defined by IEEE 80.
Soil resistivity plays a significant role in determining the magnitude of these potentials.
Reduces risk of lethal electric shock during ground faults.
Ensures equipment safety by providing a low-impedance return path.
Requires significant amounts of conductor material for large substation grids.
Highly dependent on local soil conditions, necessitating extensive site testing.
High Voltage Substations
Generating Stations
Switchyards
IEEE 80 is the standard guide for safety in AC substation grounding.
High soil resistivity increases the risk of higher step and touch potentials.
B is correct тАФ Step and touch potentials are safety hazards inherent to the grounding systems of electrical substations.
Always remember that the goal of substation earthing is to equalize the ground potential; a uniform grid is more effective at limiting step/touch potentials than deep-driven rods alone.