Flooding in the Substation Area 3

[dfopiso]

Good day to all!

Due to environmental causes, heavy rains have caused flooding in our 15/20MVA 69/13.8kV substation area. This year we recorded the worst incident - flood rose to 0.30 meters in the substation area. So far we could not see any constraint in operating the substation even when flooded because most equipment are installed on the steel structure. Will this be a concern? A new substation will be constructed beside the existing. Should we elevate this new substation or not? Any document or standard I could refer regarding this matter. Thanks in advance.

 

[sparky1976]

For start try this one. Hope it help.

http://www.usda.gov/rus/electric/pubs/1724e300/1724e300.pdf

 

[lucino]

Dafo74:
Good day!
Immediate concern maybe is on safety of personnel that would be servicing the substation.
Longterm effect I believe would be moisture that can cause cabling termination deterioration.
Future installations maybe should consider concrete platforms higher than expected flood levels so that water will not accumulate underneath the substation equipment.
Regards.

Lucino

 

[dfopiso]

Hi Lucino!

Do you mean probable electrocution? Is this the principle of "touch voltage" or potential difference between a personnel's feet with his hand? But if he is just standing without touching anything? During line-to-ground fault or overvoltage, what would happen to him? Thanks in advance.

 

[jbartos]

Suggestion: According to posted link above it should be secured from "vagaries of weather." This is very general statement; however, what if the water level doubles or tripples next time? Then, it is better to prevent the flooding.

 

[jghrist]

Make sure that the new station is built up above the 50- or 100-year flood level, depending on how much risk you're willing to take and how close you are to retirement;-). Most utilities have a very limited number of fully equipped line boats.

 

[cuky2000]

Lucino is right

Safety is a major concern not only for the substation operators but also to the public that could be in the vicinity of the facility. All safety issues related with IEEE std 80 is predicated in a 1000 Ohm foot-to-foot and foot to arm and surfacing resistance with typical value for crush rock at the substation of 2000 Ohm-m. Human skin resistance and surface resistivity could be reduced dramatically in flooded areas.

On the other hand, all reliability reports suggest that moisture is the no 1 cause of equipment failure and insulation degradation.

SUGGESTION:

a- Re-evaluate the safety issues and implications associated with run this substation in these conditions.
b- Revaluate the effect of the ground potential rise (GPR) in remote locations
c- Consider a plan for relocation of the substation.
- MV it is frequent to see installation in elevated structure.
- HV & EHV relocation could be a good alternative. New site typically is based on 100-year recurrence data.

 

[dfopiso]

Thanks alot guys! Your comments are greatly appreciated and will be considered in deciding what to do with the new substation and/or the existing one. Till next time.

 

[lucino]

Hi Dafo74.
My first comment to your post on safety is based on common sense.
The second comment is based on experience.
Sorry I cannot comment on "touch voltage" you mention.
However, I appreciated cuky2000's post.
His suggestion is worth considering. For this I give him a star.
Regards

Lucino