33kV Distribution

Smaller cables and less distribution loss from them.

Disadvantage: more insulation demands for 33kV system.

Or advantage - the thicker insulation means the cable is less prone to mechanical damage.

True: a dis-advantage!

There are several disadvantages of using 33/.415 kV transformer instead of 11/.415 kV transformer like:

• High short circuit current rating at LV side and thus increase the cost of all the equipments.
• Amount of losses will increase.
• Frequency of fault will be high.
• Size of transformer will be bigger.
• Heavy insulation is required as per the short circuit rating.

Mr. Byjuram,

Can you say where this 33/0.415 kV distribution is used, I have seen 11/0.415 kV and 22/0.415 kV in India but not the first case .

Several times problem of space occured in a small substation area where you cannot put two transformers their so we can use three winding transformer or if it is required to use only 415V we can use 33/.415 kV transformer.

There are countries that use 33kV for transmission purposes.

Why do you ask? I doubt that you'll be able to actually choose which one your power company will provide for you.

Advantages and disadvantages of 33kV/415V distribution over 11kV/415V distribution

I make more money selling 33kV gear compared to 11kV gear.

Well it's an advantage for me!

Dear Mr.byjuram,

There are several points given, the main point is for 33 KV, the Line Current comes come to 1/79.5 TIMES of the CURRENT at 415 Volts. Hence the HEATING EFFECT of the cable, which is one of the Factors affecting the CABLE LIFE is taken care.

DHAYANANDHAN.S