Alternating current (AC) | AC Generating System (Generation) | Conventional Non-Conventional systems | AC Transmission and Distribution

Alternating current (AC) | AC Generating System (Generation) | Conventional Non-Conventional systems | AC Transmission and Distribution

Hi friends here we learn about ac means alternating current in which we learn about The AC Generating System (Generation), Conventional systems, Non-Conventional systems, AC Transmission and Distribution, AC Primary Transmission

The AC Generating System (Generation):

~ The function of a generating system is to generate electrical energy.
~ Input to such a system may be thermal energy, hydro energy or nuclear energy and this input energy is converted into electrical energy by the generating system. i
~ The generating systems are broadly classified into two parts:
1. Conventional systems.
2. Non-conventional systems.

Conventional systems:

1. Thermal systems : Converting the heat energy stored in fuels like coal, oil gas into electrical energy.
2. Hydro electric systems : Converting the potential energy stored in water into electrical energy.
3. Nuclear systems : Converting the heat energy obtained by nuclear fission of materials like uranium, thorium etc. into electrical energy.
4. Diesel electric systems : Converting energy stored in diesel into electrical energy.

Non-Conventional systems :

The non-conventional systems include the systems of generating electrical energy from:
1. Solar energy
2. Tidal energy
3. Wind energy
4. Energy for. violas etc.
~ The conventional systems are used for the large scale generation of electrical energy.
~ The non-conventional systems cannot generate electncity on a big scale and therefore can be used where energy requirernent is quite smal

AC Transmisslon and Distribution:

~ The increased demand of electncnty needs more generation of electncal power. As the generation takes place it remote places, an efficient distnbution system is necessary.
~ The simplified block diagram of the High Voltage AC transmissson system is as shown in Fig. 1.5.1.
~ This system can be broadly divided into two parts:
1.Transmission system
2. Distnbution system.
~ Each part is agan subdivided into two parts: 1 Primary transmsson and 2. Secondary transmssion and similarly primary dstnbution and secondary distnbution.
~ We define transmssion and distrbution of electric power as conveyance of electrc power from the generating station to the consumers.
~ The electric power transmission may take place methods as follows :
1. By overhead system 2. By underground system.
~ Generation and transmission now a days is always three phase. The secondary transmission is also three phase whereas the distribution to the customer may be three phasei or single phase depending on the requirement of the customer.

AC Primary Transmission

In Fig. 1.5.1 the central station CS generates power using three phase alternators at 6.6 or 11 or 13.2 or 32 kV. This voltage is then stepped up by suitable three phasei transformers, to 132 kV as shown.
~ Such a high voltage of transmission requires conductors of smaller cross section which results in the reduction in the costi of copper or aluminium.
~ However the cost of insulation increases. The transmission voltage is therefore determined by economic considerations. Higher transmissions voltage also reduces the line losses and improves the efficiency.
~ The 3 phase three wire overhead high voltage transmission line gets terminated in the step down transformers in a sub station known as Receiving station (R.S).
~ Receiving station is usually situated 0utside the city in order to ensure safety.
~ Here to the voltage is stepped down to 33 kV from 132 kV.