Engineering-xls: Touch Voltage & Ground Current Calculation Excel Sheet

Tuesday, January 29, 2019

Touch Voltage & Ground Current Calculation Excel Sheet

File Size: 99 Kb

Touch Potential is the potential that can be established between the point at which a person is standing on the ground and the point at which some contact is made with hardware, such as by placing the hand on a substation fence.

Engineering standards use a one-meter reach distance for calculating Touch Potentials. A two-meter reach distance is used when two or more objects are inside the event area. For example, a person could be outstretching both arms and touching two objects at once such as a tower leg and a metal cabinet.

Mitigating Step and Touch Potential hazards is usually accomplished through one or more of the following three main techniques:

Reduction in the Resistance to Ground of the grounding system
Proper placement of ground conductors
The addition of resistive surface layers

Understanding the proper application of these techniques is the key to reducing and eliminating any Ground Potential Rise hazards. Only through the use of highly sophisticated 3-dimensional electrical simulation software that can model soil structures with multiple layers and finite volumes of different materials, can the engineer accurately model and design a grounding system that will safely handle high-voltage electrical faults.

According to the inputs for three-phase system:-

Line-to-Neutral Volts (Vn), Line 1 Calculated Load (A1), Line 2 Calculated Load (A2), Line 3 Calculated Load (A3), Service Neutral Impedance Z1, and Ground Resistance (3-point method) R, spreadsheet will calculate the following parameters: