Why all voltage levels are the multiples of 11KV?
- 10 Answers
- 50932 Views
- KSEB, I also Faced
- E-Mail Answers
Answer Posted / shreekar
Let us say transmission voltage is Vt and generated voltage is Vg.
According to some people Vt is 10% more than Vg [because 10% is transmission line drop]. Hence Vt = 1.1 * Vg ----eq1.
According to some people Vt is a multiple of form factor i.e Vt = 1.11 * a ----eq1.
where 'a' is some voltage.
When we see these two equations i.e eq1 and eq2 there is lot of resemblance.
Why form factor theory is correct?
Now in India transmission line voltages are 11kV, 33kV, 66kV, 220kV.
Here the transformer ratio is greater than or equal to 2, between two consecutive transmission line voltage, so electrical engineers use 3- PHASE TRANSFORMER. Hence line voltage is a multiple of form factor (i.e 1.11).
But this is not always true for higher transmission voltage like 400kV and 765kV (Note: 400 and 765 are not multiple form factor). The transformer ratio between 400kV and 765kV is less than 2, this is true as we move to even higher transmission voltage 800kV and so on. If transformer ratio is less than 2, then Electrical Engineers use AUTO-TRANSFORMER (this is because of economical reasons). That is why you have to take phase voltages after 220kV.
Hence, Phase voltage [The reasons to take phase voltages is because of AUTO-TRANSFORMER] of 400kV = 400/1.73 = 231.2kV
231.2kV is near to 220kV and 220 is a multiple of form factor. (this approximation because of corona discharge and it is related to Insulator string efficiency, Tower size and
dimensions of Conductors). [Note: Corona loss depends on transmission line voltage]
Similarly, Phase voltage of 765kV = 765/1.73 = 462kV which is near to 440kV and 440kV is a multiple of form factor.
In the contrary,
you cannot say transmission losses is always below 10%. Some time it may exceed 10%. In major cases it dose not exceed, but who knows what happens the whole power system is a dynamic system.
Conclusion:
Hence transmission line or phase voltage are multiples of form factor. We have to consider phase voltage only when we encounter AUTO-TRANSFORMERS and not the line voltages.
| Is This Answer Correct ? | 0 Yes | 0 No |
Post New Answer View All Answers
Can we put 3 layers of cable tray while installing tray
and gate circuit diagram,amplifier circuit diagram
what rectifiers is and what are the types of rectifiers?
What is conventional thermal current (Ith)
WHAT IS THE CURRENT CARRYING CAPACITY OF 2.5/3 CORE HI TUFF CABLE,WILL IT SAFLEY CARRY 8.6 AMPS OVER 120 METRES,CAN YOU ALSO ANSWER WITH FORMULA FOR WORKINGS OUT ,THANK YOU 3RDYR APPRENTICE.
How o select the electrical fuse?.What are its characteristics.How to select the material od fuse?
Electronic circuit
How to arrange a hous hold earthing system to keep minimum earth resistance( below 7ohms).
How to megger test 11 kV cable and the acceptance IR value
AL=0B9H,bl=75H, ADD AL,BL AL=____________? CF________? OF___________?
earth also having a gravitational force (magnetic field of north and south)but it attracts any object compare to this theartifical magnetic cant perform same as earth why?
Explain about retrofitting of machine tool.
why do we put a transformer on soak before loading it
What is the basic of DTH.
WHTA IS LIMT OF LEAKGE CURRENT OF 11 KV 1 CORE 1000SQ.MM. XLPE CABLE.LOAD ON CABLE IS AROUND 600AMP .LENGTH 500 MTRS.
