Electrical Power System Earthing is an intentional or accidental connection of some equipment to the ground. Earthing of power system represents the earthing of the neutral wire of distribution transformer. There are several earthing system which use in this power systems. Equipment earthing represents the operation of the equipment at low potential level.Since the neutral wire of the transformer got some potential difference with respect to the ground so touching neutral wire can be very dangerous. Earthing of power system also represents the operation equipment and system at low resistance path. Earthing or ground can mainly subdivided into two main section s such as System Earthing and Equipment Earthing.
Types of Electrical Power System Earthing
System earthing types of power system can mainly classified into Solid earthed ground and Impedance ground. The impedance ground can further subdivide into resistive grounding and reactance grounding. System Earthing can further subdivide into Solidly earthing, Impedance earthing and isolate neutral. If we simply say system grounding is the earthing of the neutral wire of the system .
Solidly earth system is on which has the neutral connected to ground without an intentional impedance. The main advantage of this solidly earth system is the size and the cost of the transformer are reduced by grading insulation toward neutral point. In low voltage system the solid earthing system are much more effective
Impedance Electrical Power System Earthing
The impedance earthing is also sub divide into main category such as resistance earthing and reactance earthing. Impedance grounding are intentionally connect the equipment in to ground. Resistance and impedance grounding can use to operate under live condition.
Resistance Electrical Power System Earthing – In impedance earthing or resistance grounding is the system which is on that has neutral connect to ground . This is also connect through a small resistance which make barriers for fault current. In this earthing system the resistance of the equipment is intentionally connect to the ground for protection.
Reactance or Capacitance Grounding – Reactance earthing is done at lower ground fault current amount. This type of earthing system are widely used to protect generator. In this earthing system the reactance or capacitance of the equipment is intentionally connect to the ground for protection.
Equipment grounding of the power system represents the operating equipment at low potential level .Normally a wire is connect between the equipment and to earth to provide a low voltage path. This ground places an operation equipment at ground voltage level. The conductor is also use for this equipment earthing.Through equipment earthing the whole equipment is connect to the ground.
There are two main type of earthing systems are use to protect system.
Three Point Test- This three-point test require a complete disconnection from the power utility system.
Induced Frequency Test– The induce frequency test use to perform while power is on. Actually requires while the power to be connect to grounding system on under test.
Hope that you have understood the basics of Electrical Power System Earthing and we are plan to discuss more on other earthing systems in future.