HIGH VOLTAGE POWER SUBSTATION

High Voltage Substation

Substations  are the points in the power network where transmission lines and distribution feeders are connected together through circuit breakers or switches via busbars and transformers

This allows for the control of power flows in the network and general switching operations for maintenance purposes

The first step in designing a power substation is to design an earthing and bonding system

Earthing_and_Bonding#

The function of an earthing and bonding system is to provide an earthing system connection to which transformer neutrals or earthing impedances may be connected in order to pass the maximum fault current. The earthing system also ensures that no thermal or mechanical damage occurs on the equipment within the power substation , thereby resulting in safety too peration and maintenance personnel. The earthing system also guarantees equipotential bonding such that there are no dangerous potential gradients developed in the substation

 :In designing the substation, three voltage have to be considered

Touch Voltage: This is the difference in potential between the surf ace potential and the potential at an Earthed equipment whilst a man is standing
and touching the earthed structure

- Step Voltage: This is the potential difference developed when a man bridges a distance of 1m with his Feet while not touching any other earthed equipment

- Mesh Voltage: This is the maximum touch voltage that is developed inthe mesh of the earthing grid

High Voltage Substation