In electrical installations if a system that has no ground reference earthpoint at all, it is not easy to correctly find the faulted location. It is hard to figure it out due to the absence of a clear conducting path to ground, the earth fault remains undetected. In case of a second earth fault happened in the line that is not affected in the system, it could make a short path and result in high fault current that would trigger protection devices. Hence, electric ground refers to the connection of the neutral point to an earthpoint.
In order to detect the first earth fault point in the electrical circuit as soon as it happens without waiting for another fault to happen, you should do Electric Grounding to one of the two poles of the source (S) (Grounded electricity supply) . The pole which is electrically grounded also called the neutral and the other pole called ‘line’. The connection between neutral and earth lead should only be at the source (S). The current returning from the load passes only through the neutral conductor going back to the source. As we applied grounded electricity at the supply side, the neutral is usually isolated from the ground and also similar isolation in the line conductor.
When an insulation failure occurs in the line conductor, a relatively high current passes through the electrical circuits going to the ground path back to the source (which is has grounded electricity) and according to the earth resistance of the ground path, the current passing in this path can trigger a protection device.
Hence, The main Purpose Of Electrical Grounding System is allowing easy detection of earth faults in the electrical systems via providing a path for the earth fault currents from the faulty point through the earthpoint back to the neutral point of the source.
Neutral Electrical Grounding Techniques
The following types of earthing are the most common types:
The main advantage for under grounded systems is that when an earth fault occurs in the system containing ground, the resulting electrical currents are very small that they don’t affect the system. Therefore, the system could continue without any interruption.
In industrial electrical applications, any electric power cut is going to be very expensive and often converted to loss of production, So if there no system for electrical grounding, it could affect the life threat to human beings (no ground protection).
Electrical grounding systems are not expensive and any electrical system should provide a earth protection for its equipment
Solid electrically grounded systems
In these systems the solid grounded system is achieved when we connect the system neutral directly to the ground ( earthpoint ) without connecting any resistance in the path to ground. When you have a good design and suitable number of earth electrodes and right choice of their material, you can have a very low ground resistance, you can reach up to 0.5 Ω resistance.
The solid electrical grounded system provides earthing and bonding to the neutral tightly to ground and guarantees that when there is an earth fault in one phase, the electrical voltage of the other phases (which are in good condition) does not go to higher values than the value under the normal condition in operation.
In this system, an earth fault is detected and thus it will be isolated rapidly by circuit protection devices. Usually, the short circuit earth faults protection is enough to detect and isolate and break the earth faults.