thank you all for your valuable feedback (I should have shared following details beforehand)
this is a special project with following details. it has residential, hotels, government offices, cultural & educational centers etc. compacted in small area (a luxury compacted city build in small area).
- land area - 275 hectare
- population -300,000
- total expected maximum demand - 250 WM
- total demand- 500 MW
we are to justify a suitable distribution voltage for this special project. based on the feedback and details observed so far, i have summerised below details,
advantage of 22kv
1)Reduce by 50%
- space requirement for laying cables
- No of feeder bays
2)For double the capacity
- Increase only by around 10% to 15% cable cost
- Small price difference between 11kV and 22kV panel -design the panels for 22kV and fix 12kV equipment
3)Low energy loss in MV network
4)Low energy loss in HV equipment- 220kV can be directly stepped down to 22kV
5)No much difference in operation & maintenance of 11kV & 22kV cables & equipment
why 33kv is not best for this kind of project
1)33kV is a sub transmission voltage not a distribution voltage.
2)Cables and equipment very expensive.
3)RMUs are very expensive and very rare.
4)Cable systems are difficult to handle, operate & maintain.
5)Need more space for switch gear and cables
6)High fault level.
7)Cable capacitance would be high and need to have reactors at GSS
are there any technical matters we should consider beyond this. Especially I'm missing with accurate pricing details of cables and RMU/Switchgears (pricing comparison of 11kV, 22kV and 33kV).
Further in some posts I saw that having higher fault levels is good when considering starting of large motors etc. where neighboring consumers won't feel much (So, is 22kV better than 11kV)
Are there any examples where this kind of projects were carried out using 22kV (instead of 11kV)