Sudden Reduction of Load

[vavanapoly]

hi every body
i am facing a strange problem
we have a generation power station that feeding 8 OHL MV 13.8kv feeders
and in one specific feeder @ peak load ( 4.2 MW ) suddenly the load goes down for 2 MW and then retain gradually to 4.2 MW withen 3-4 minutes.
we checked the OHL and nothing found.
and the poeple in the generation side saying that the problem is not fron their side.
is there any way to locate the source of this problem ? and is there some kind of a protection relay that could act like this during specific conditions?

 

[itsmoked]

Sounds like maybe your generator voltage regulator is taking things for a ride? Just a guess. But they say no..

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[Skogsgurra]

Load shedding somewhere? You were at peak load..

Industrial process that had a hicup? Some pick up load again in that interval.

Can't be many large loads on a 13.8 kV feeder. Give them a ring to find out.

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[slavag]

Each day, same time or it's randomaly.
If it's have some time sequency, it's seems as industrial process. Call to your customers and check with them.
As Gunnar say, it's also seems as LS and load restoration
or as decoupling and re-connection to grid.
Maybe you have on this line customer with generator with paralell operation to grid.
In all cases you need check this with customers.
Regards.
Slava

 

[jghrist]

Is this the only source of power to the load?

 

[vavanapoly]

i am thinking about the lightning arrestors
is it possible that we have one lightning arrestor which is not working as designed?
and is there some kind of a protection relay that could act like this during specific conditions?
and there is any industrial consumer at that feeder?!

 

[Rodmcm]

If the sum of all the MW into the busbars is zero then you are experiencing a drop in load on the overhead line. If not then maybe you have a metering problem on that line. Can you check it from multiple meters ie tarrif, metering, protection?

 

[jghrist]

i am thinking about the lightning arrestors
is it possible that we have one lightning arrestor which is not working as designed?

If lightning arresters drew a significant load, they would fail thermally very quickly. I don't think this could be the problem.

 

[waross]

Most faults result in increased loading. Losing load is usually just that; losing load.
I am going to check the Electric motors & motor controls engineering forum now and look for a post that goes
"For some reason all the motors in our plant drop off line together. It takes us 3 to 4 minutes to restart everything. Managment is furious."
This would be the first most probable cause. (And the second most probable and maybe the third also.)
respectfully