Advantages of MV Diesel Generator VS LV Diesel Generator

Dear Sir,

Please let us know in your openion what is the value of LV & MV ( in volts).

By MV do you mean HT DG sets ? The cost of LV set plus the Transformer &

associated control gears ( Capital & Maint.costs ) is to be weighed against the

cost of HT DG set and the other controls is to be seen before taking a decision.

manroop.Chennai.

dear sir,

thank you indvance for your attention.

we bought 6.3KV 2440KVA at 0.8lagging power factor and one step down 6.3/0.4KV step down transformer in lieu of our client said you should use 400v 2440kva plus one step up transformer 6.3/0.4 KV before transmision line finaly at place of power house use step down transformer 6.3/0.4 KV before main essential distribution bord.

now with above mention explanation i try to convince him due to MV diesel gen.

i think there are following benefits atleast:

1. simplicity of design because of less appliances and increase reliability of system consequently.
2. deminishing of total loss because of lesser trans.
3. deminishing of construction cost
4. foresee capability to transmit power into other long distance place as emergancy power reserve.

Dear Sir,

Excuse me for my delayed reply. Your client's choice of LV set &

stepping Up and down may be from the point of transmission distance. Let me

put forth my views. (1) 2440 Kva ( 2.5 Mva) @ 6.3 Kv will have a load current

of 225 Amps and this has to be transmitted to the point of usage. Your scheme

seems to be ok - technically. Transmit the power through Over Head Lines OR

HT UG cable , stepdown to 400 V for usage.You will avoid losses. You will have

choose the conductor size with suitable derating factor.

(2) Your client's proposal to have LV set & etc will involve heavy

capital cost. As on date you have to go for multiple LV sets ( 750 Kva x 3 Nos)

& (500 Kva x 1) to get 2440 Kva ( 2.5 Mva). The load current for 750 Kva will

be 1083 Amps and for 500 Kva will be 721 amps. These currents are @ 400 Volts.

The sub station design , Syncronisations , Load Sharing will be a problem for you.

With all you have to step up , Transmit, step down at the load point. Just imagine

how will you transmit 3608 Amps ( 400 v) - Cable sizes , No of runs, derating

factors, safety etc.

Please explain my views to your client my and make him see the

reason. Wish you good luck.

Manroop - Chennai.

What is the power that is generated (and of course transmitted?)