In this article we will know about what is basic adavantages of hydrogen cooling in electrical machine. we will study abut the basic advantage of hydrogen cooling in electrical machine.
Advantages of Hydrogen Cooling In Electrical machine
The utilization of hydrogen for the cooling of electrical machines gives the following advantages . These are some advantagese of hydrogen cooling in Electrical Machine.
Advantages of Hydrogen cooling in Electrical Machine.
1. Increased in Efficiency of Electrical machine
An increase in efficiency results from reduction in the ventilation losses (like windage) which are a major portion of the total losses in a high-speed machine. This is because the density of hydrogen is only 0.07 times the density of air and therefore the power required to circulate hydrogen should be about 1/14 of the power required for an equivalent quantity of air. In practice, the power required is about 1/10 of that for air when hydrogen is 98%.
Calculation show that in 50MW and 100 MW turbo-alternators with hydrogen cooling the efficiency is raised by approximately 0.8 percent at full load attaining values of 99.0 to 99.2 percent. Increased in efficency in machine is very usefull advantage of hydrogen cooling of electrical machine.
2. Increase in Rating of Electrical Machine
Hydrogen has a heat transfer coefficient 1.5 times and its thermal conductivity is 7 times that of air. Consequently, when hydrogen is used as a coolant, the heat is more readily taken up from the machine parts and given out. Therefore, heat generated is more effectively removed and active materials can be loaded more than is possible with air-cooling. The high of thermal conductivity of hydrogen, the temperature gradients across the film barrier between cooled surface and coolant and across the coolant are reduced. Because of the above two factors, an increase output can be taken from a given frame size if hydrogen cooling are not there.
3. Increase in Life of Electrical Machine
The life of a machine is mainly the life of winding insulation and air pockets in insulation can be sources of such high local temperatures that there is always the risk of insulation breakdown and fire. The thermal conductivity of hydrogen is nearly seven times that of air and is of the same order as the winding insulation. When, therefore, there are pockets filled with hydrogen, heat conduction through them will be as good as through winding insulation and consequently high local temperature rises are not there.Increase in life is main advantage of electrical machine because it reduce cost of system. these are also main advantages of hydrogen cooling in electrical machine.
When air is used as a coolant, the high voltage winding can fail due to destructive action of corona discharge. This is because air contains oxygen and nitrogen and during corona discharge ozone, nitric acid and other chemical compounds are formed which attack organic material in the insulation. On the other hand, when hydrogen is used as coolant, sufficient oxygen to form ozone and destructive compounds in the event of corona discharge is not present. The danger from this source is, therefore, greatly reduced. Hence, the use of hydrogen is a coolant greatly increases.
4. Elimination of Fire Hazard in Machine
The outbreak of fire inside the machine is impossible, as hydrogen does not support burning.It is also main advantage of hydrogen cooling in electrical machine .
5. Smaller Size of Coolers of Electric Machine
The size of coolers requires cooling the gas smaller when hydrogen is used as a coolant.This is also provide advantages of hydrogen cooling in small electrical machine.
6. Less Noise in Electrical machine
The noise produced by a hydrogen-cooled machine is less as the motor moves in a medium of smaller density.
Hence these are basic advantages of hydrogen cooling of electrical machine . we have studied that electrical machine efficency increase , less noise, increase in life of machine . if you will find any incorrect in above please comment in below.