POWER ASSIGNMENT

Power Assignment and details attached



Power Assignment and details attached

Question number 01:

The first from of power used in mines was DC. From 1870's to 1880's the DC power systems were common practice. Usually small DC systems were deployed in factories commercially throughout the world as well as in cities for domestic purposes. The requirement of electrical power in rural a remote area such as mines was also fulfilled using DC supplies.

DC power systems were able to provide power only on small scale and almost 95% population of the cities was remained un-electrified. It was suggested to generate the power in bulk at one place so that it could be transmitted to a large factory or city. Mines are also very large which can be up to several miles in length that's why DC power systems were used primarily and later replaced with AC ones. (http://edisontechcenter.org/HistElectPowTrans.html)

Question number 02:

Distribution voltage is the voltage which is transmitted from the power station in to the grid. It is voltage across the transmission line. Whereas utilization voltage is the voltage at which load devices are operated. The power dissipation through a conductor is represented in terms of current as:

P = I2R

Where,

I = Current

P = Power dissipation

R = Resistance

From the above equation it can be concluded that the power dissipation is directly proportional to the square of the current and resistance. In order to minimize power losses the value of resistance of the transmission line should be kept low if the current is AC. According to Ohm's law:

V = IR

R =

It is apparent that in order to minimize the power dissipation the voltage should be increased and current should be increased. That is the reason why distribution voltage is higher than the utilization voltage.

Demand

There is constant load demand in mines. There are relatively small number of large machines (loads) are operated at a very high voltage. There is no natural load when it comes to power consumption at mines.

Peak load

The maximum load in the mines is always equal to the peak load as the heavy machines are to be operated constantly without any interruption. So the load requirement at the mines is always equal to the peak load.

Maximum Demand

It is defined as the maximum electrical power requirement in a grid. In mines maximum demand is defined as the power requirement when all the machines are to be operated at their maximum capacity simultaneously.

Demand Factor

It is mathematically defined as

Demand Factor = Maximum demand of a system / Total connected load on the system

For example: if a mining operation having 12000W machine connected has a maximum demand of 6000W, then

Demand factor = 6000W / 12000W = 55%.

Diversity Factor

Diversity Factor = Installed load. / Running load.

Diversity factor is usually greater than one. The load varies with time as well as the characteristics of the machines which are operated in mines. Diversity factor helps to determine the fact that total load is not equal to the sum of all the loads which are connected in a grid ...