How Electricity is Deliver to your Home

Electricity is generated from generation stations such as HEP (Hydro-Electric Power), Solar, Geothermal e.t.c and are interconnected together by the grid system.

Generally, electricity used in homes comes from a very far distance and involve a whole lot of process before it finally gets to your home. This process can be classified into 3 main parts which are:

 1. Generation
 2. Transmission
 3. Distribution

1. Generation 

It is the root process where electricity is been generated. This generation of electricity comes from various source such as: Hydro-Electricity Power (HEP), Geothermal, Natural Gas, Biodiesel e.t.c. The generation of electricity is usually at a voltage level of 16kV at a frequency of 50Hz and step up by the station transformer to a voltage level of 330kV and because of the fact that its been generated from different location and source there is therefore need of interconnecting all this power station together to a network known as the national grid so as to enhance stability. The generated voltage is a 3 phase voltage.
In Nigeria electricity generation is usually regulated by the National Electricity Regulatory Commission (NERC). Typical example of generating station in Nigeria are: 

- The Hydro Power System
          Kanji Dam in Niger State , 
          Jebba dam in Kwara state and 
          Shiroro Dam in Kaduna, 

- Thermal Station
         Egbin thermal power station at Egbin, Ikorodu, Lagos State, 
         Alaoji Power Station in Abia state e.t.c

- Gas Power System
         Okpai Power Station in Delta State, 
         Egbema Power Station in Imo State
         Geregu Power Station in Kogi State e.t.c

- Coal Power Plan
         Enugu Coal Power Plant in Enugu 
         Itobe Power Plant in Kogi State  

         and so on.

2. Transmission: 

* Primary Transmission System
The 330kV is transmitted/transported over a long distance transmission through the national grid across a transmission line and stepped down by a substation transformer to a voltage level of 132kV by a substation transformer. It is usually a 3-wire system and the insulator used is called the Strain insulator.

Transmission Line (Pylon)

 * Secondary Transmission system
This voltage is further transmitted and stepped down by another substation transformer to a voltage level of 66/33kV. In Nigeria this is usually done by the Transmission Company of Nigeria (TCN) and Niger/Delta Power Holding Company (NDPHCN) under the National Independent Power Project (NIPP). This transmission line is the one you normally see on the Tower(Pylon) mostly inside the bush.

 

3. Distribution: 

This is the last phase of power transportation. Because the 33kV gotten from the transmission station is far too much to what we need for our normal household utility it is therefore not possible for us to utilize this high voltage level. Even our household appliances such as: TV, DVD set, Fridges e.t.c uses 220-240V only for there operation, you can confirm this at the name plate printed at the back of any of your household appliances. It is however suitable for some industrial application. So some industry employs the use of 11kV or 33kV for there operation.

33kV pin insulator

*Primary Distribution System
Because of this scenario, a distribution transformer is introduced which steps down this voltage from 33kV to 11kV (feeders) and distributed to different community through the injection station. This distribution transformer is usually a 3-phase 3-wire system and you will identify it more clearly by its insulation (pin insulation) and the number of conductor that enters and leaves the transformer; 3-conductor comes in as input and 3 conductor goes out as the output. 


* Secondary Distribution System
This 11kV is further step down by a secondary distribution transformer to a voltage level of 415V. This transformer is the one you normally find at the street corner of your house and it is the one that is responsible for supplying the necessary voltage of 220-240V system needed by your home. You will identify this type of transformer more by the number of wire that enters and goes out of it, 3-conductors (3-phase) usually enter and 4-conductors come out as its output the fourth one been the neutral conductor.

Power distribution is done by the Distribution Companies of Nigeria (DISCO) . We have 11 distribution station in Nigeria states. Typical examples are: 
The Ibadan Electric, 
Eko Electric, 
Ikeja Electric, 
Enugu Electricity Distribution, 
Benin City Distribution Comapny, 
Jos Electric Distribution and so on.


I hope this simple analysis explain the fundamental of how electricity gets to your home...
Thanks.