Switchboard Maintenance & Calibration (Part 1)

Building Main Intake from Utility

 

What does it mean by utility?

Electricity from the Power Company 

• Electric utilities transmit power from the power plant most efficiently at very high voltages. 

• In the United States, power companies provide electricity to medium or large buildings at 13,800 volts (13.8kV). 

• For small commercial buildings or residential customers, power companies lower the voltage with a transformer on a power pole or mounted on the ground. 

• From there, the electricity is fed through a meter and into the building.

Transformer for Building

Transformer for Building

What are the parts of transformer?

• §                 Core
• §                 Winding
• §                 Insulation
• §                 Tank
• §                 Terminals and bushings
• §                 Transformer oil
• §                 Oil Conservator
• §                 Breather
• §                 Radiators and fans
• §                 Explosion vent
• §                 Tap Changers
• §                 Buchholz relay

Why do we need to install a power transformer for each high building?

I live in area where many high buildings are being built. Each building is more than 10 floors. A special room is made next to the main entrance or the garage. The room is designed for installing a power transformer inside it. The room also provides good ventilation. The primary coil (winding) of The transformer is 11 kV and the secondary coil is 380/220 V

Why do we need to install a transformer for each building?

You have to have the transformer from 11 kV to 380Vsomewhere. If it's far away from your buildings, you have substantially increased transmission losses. If you had one big transformer close by all the buildings, those losses would be substantially mitigated. But there are still a few disadvantages.

Electrical supply

• Supply to building shall be taken from national grid. 
• The incoming supply shall be trenched underground in such a manner that it is outside the zones identified for future extensions to the building.
• The load requirement shall be reviewed.

Electricity Switch Room

• The Electrical Switch Room shall be housed in a dedicated room / cupboard located on the ground floor and in association with an external wall and shall have internal access. 

• The room shall be located so that; 

It does not present difficulties for services distribution from adjoining plant spaces or rooms. 

To provide for economic distribution of services.

• The main switchboard shall be of metal clad cubicle design to approved standards and regulations. 

• Each switchgear assembly shall have a minimum 25%spare capacity. 

• Electronic surge protection shall be provided on the incoming mains.

Electricity Switch Room

This blog is written to facilitate researchers and students from higher education for summary notes that can bring back memories.

This brief note is provided by UTHM Lecturers from the Faculty of Technical and Vocational Education.