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LESSON NOTE for. APPLIED ELECTRICITY SS3. POWER TRANSMISSION AND DISTRIBUTION. In a generating station, electrical power is obtained by the generators at 11kV or 16kV depending on the generating station. This is step-up to 330kv by generator transformer.
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LESSON NOTE for APPLIED ELECTRICITY SS3
POWER TRANSMISSION AND DISTRIBUTION • In a generating station, electrical power is obtained by the generators at 11kV or 16kV depending on the generating station. • This is step-up to 330kv by generator transformer. • Transmission of this electric power starts at 330kV to a primary injection substations.
In Nigeria, transmission of electric power is done by transmission lines at low frequency of 50Hz, either by underground cables or overheard lines on poles or towers. • The transmission lines are usually steel-cored aluminum or hard drawn copper. • The transmission of electric power is usually at very high voltage and low frequency because P= I²R (power loss) • The higher the voltage, the lower the losses and the cheaper the supply.
The main components of the transmission line system are e, transformers, cables, circuit breakers, distribution boards, towers, insulators, conductors etc. • Distribution differs from transmission mainly because of their voltage magnitude. • The voltage level in distribution is lower than that of transmission • The number of branches is higher in distribution and the general structure varies with location • The two main types of distribution/transmission are the radial and ring system.
Radial system is electric transmission or distribution system which begins at a central station and supplies power to various sub-stations mainly in rural areas. • Ring or Loop system starts from the central station and makes a complete loop through the areas to be fed and back to the starting point.
EVALUATION • State the voltage level at primary transmission. • What is the frequency of generation in Nigeria? • List the two main types of distribution systems.