Comparative Benchmarks for Various Grounding
Methods |
| |
Methods of Grounding |
| Characteristics |
Ungrounded |
Solid Grounded |
Low Resistance |
High Resistance |
Immunity to transient over-voltages |
Worst |
Good |
Good |
Best |
Increase in voltage stress under line-to-ground
fault conditions |
Poor |
Best |
Good |
Poor |
Equipment protected against arc fault damage |
Worst |
Poor |
Better |
Best |
Safety to personal |
Worst |
Better |
Good |
Best |
Service reliability |
Worst |
Good |
Better |
Best |
Maintenance cost |
Worst |
Good |
Better |
Best |
Continued production after first ground fault |
Better |
Poor |
Poor |
Best |
Ease of locating first ground fault |
Worst |
Good |
Better |
Best |
Permits designer to coordinate protective
devises |
Not Possible |
Good |
Better |
Best |
Ground fault protection can be added easily |
Worst |
Good |
Better |
Best |
Two voltage levels on the same system |
Not Possible |
Best |
Not Possible |
Not Possible |
Reduction in frequency of faults |
Worst |
Better |
Good |
Best |
First high ground fault current flows over
grounding circuit |
Best |
Worst |
Good |
Better |
Potential flashover to ground |
Poor |
Worst |
Good |
Best |
