Designing 11-kv Networks

When you say network, are you speaking of connection all of the secondaries together or the primary feeders together?

of course we are talking about connecting the primaries not the secondarys

thank you

Hi wassoo,

From what brief thread you put it appears that you want to design a power distribution system with 2 incomers and nine 630 KVA transformers at different locations with LT distribution panel. Please make a single line drawing of your system and make estimate of materials required and labour cost.

1) Main Distribution Panel with incomers, CT ,PT and protective relays,indicating instruments for kV , kVA , kVAR, Power factor,energy meter , Maximum Demand meter, rotary switches ,push buttons, indicating lamps , Battery etc.

2) 2 Numbers Incomer Breakers with capacity to handle the total connected

load with a breaker for bus coupler.

3) 9 Numbers. Outgoing breakers, cable and if the transformers are located far off then additional HT breakers then transformers and LT Panel with necessary LT switch gear and protective system.

4) if two transformers are to be installed at single location then bus coupler arrangement can be done for LT Bus bar also.

Hi,

Thank you for your rapid response and I'd like to brief the following

1. we have a big complex which has the nine 630KVA substations proposed by the original designer
2. a nearby 11kv substation is already there
3. my ambiguity is how to link and design for such project and how can we sugest the no. of 11/0.4kv transformers on the 11kv feeder
4. the quitionair is that I used to design the L.T side i.e from the 400V, boarding, cabling and other sysytems but never got through the 11kv sysytems
5. please if you can advice for that I will grateful

I would suggest that you go for a ring mains system with a central incoming 11KV switchgear with two incoming feeders.

Incoming breaker rating 2 nos : 630A,

common busbar with metering .

Bus tie breaker - 630A

Outgoing feeder breaker rating - 2 nos Feeder 1, Feeder 2 - 630A

Feeder 1 going to transformer substation no 1 - cable size 3C240sq mm

Transformer substation 1 will comprise of one incoming feeder load break switch 11KV- 630A, one outgoing feeder load break switch 630A - 11KV to transformer substation no 2, common busbar and one 11KV fused switch to transformer.

Similarly all transformer substations to be linked.

And the ring to be completed via feeder no 2 back to substation.

The ring must be kept open at one substation and remaining switches closed.

Main substation and transformer substations are available from major suppliers such as ABB, Schneider etc.

Also note that the circuit breaker ratings must be adequately sized as per fault level at incoming feeder. This information is normally available from the power supply company.