Wednesday, September 30, 2009

Use of electric power for heating purpose

Electrical energy for heating purpose - As we said earlier, any form of energy can be obtained from electrical energy. Heat is the one thing which we need in day to day life. Iron box, room heating equipment, water heating are the main electrical equipments where electrical energy is converted in to heat.
The process involved here is simple. There are some metals which have high resistivity. The loss due to this resistivity can be obtained from the formula I*I*r. I is the current flows through the conductor and the r is the resistance of metal. Heat is produced as a result of this loss. This principle is mainly used in many heating equipments.
When electrical power is passed through this metal heat dissipated. This conductors are placed as coils, this coil are known as heating coil.
The power consumption of this equipments are more than lighting equipments.

Sunday, September 27, 2009

Power loss in electrical system - Losses are the main factors which is to be considered in power engineering. From generating station to distribution station power loss takes place in many ways.
In generating station, the mechanical energy can not be converted in to electrical energy. In step up process, due to eddy current and thick core of transformer power loss takes place. Transmission is the main place where power loss need to be reduced. There is no conductor which transmits power with out loss. Before discuss about power loss, we need to know about eddy current.
when current pass through thick conductor due to induction small amount of current generated which opposes the main current. This current is directly proportional to the thickness of conductor.
This is the reason why all the conductors are made not in single thick wire. Instead it is bundle of thinner wires. Copper is mainly used as conductor as it has less resistivity compare to other conductors. Overhead lines are placed in parallel.
Current flows in one wire induces some voltages in another wire. Due to this voltage small amount of current flows which further induces some power losses.

Wednesday, September 23, 2009

Distribution of electricity

Distribution of electrical power - Distribution starts from substation. Transmitted power stepped down here. This power further transmitted to the loads. One more transmitted located near to the loads which always step down transformer. The voltage level is further reduced and supplied to the domestic loads.
The voltage which reaches the domestic load will be 240 V. This distribution may takes place in two types. 1. Underground lines 2. Overhead lines. In crowded area, underground transmission is preferred. AC type is used in this entire distribution process.
Transmission of electric power can be in two ways. 1. AC power transmission 2. DC power transmission. In DC method, converters and inverters can be used. DC method preferred only if the transmission distance more than 1500 km. In case of industry loads, the distribution power level is higher than the domestic level.

Monday, September 14, 2009

Electrical Transformers

Transformers - Transformers play vital role in power system. It mainly used to step up and step down the voltages. This can be classified in to two major categories. 1. Step up transformer 2. Step down transformer. Voltage in the transformer is directly proportional to the number of windings in the transformer. In step up transformer number of turns in secondary are more than primary turns. The output voltage of step up transformer is higher than primary voltage.
Number of turns in the secondary windings are less than primary winding. This is known as step down transformer. Step up transformers are mainly used in power stations where generated power is step upped for the purpose of transmission. Step down transformers are mainly used in substation where the voltage level of transmitted power is reduced for distribution purpose. Cooling of transformer winding is the one to be taken care.
Transformer oil is used for this purpose. Cooling of transformer will be seen in future.

Saturday, September 5, 2009

Nuclear power station

Nuclear power station - The world is looking for nuclear power generation as the need of electrical power increasing dramatically. The reason behind this is, only small amount of source is more than enough to produce huge amount of power.
Nuclear fission or nuclear fusion are the methods mainly used here. When any one of the above said process takes place, huge amount of thermal energy generated. This thermal power is used to generate high temperature steam. Only difference between thermal and nuclear power station is that nuclear source is used to generate heat. The advantage of this power station is that, only small amount of source is enough compare to thermal power generation. The main disadvantage is that, it is dangerous to human. If any accident takes place then the entire area will be affected. The radiation is more dangerous to human being. The disposal of nuclear waste is difficult process. In nuclear power stations, reactor is placed only below the earth level to avoid radiations.