Disconnectors 1

[PowerGrad]

Currently I am looking at replacement criteria for Disconnectors. Many people want the disconnectors replaced in their substation but I am not always sure why. For example, it seems that Hot Spots are usually caused by dirt - so why should a disconnector have to be replaced because of them? What are the common problems and faults you have experienced with disconnectors (I have heard it said they are the weak point in the substation) and under what circumstances should they be replaced.

Many Thanks in advance

 

[Overvoltage]

I'm assuming you're talking about disconnect switches. Most of the problems I have seen have been related to alignment of the mechanisms or not making good contact. Most of those issues can be resolved through good maintenance, cleaning, and repairs as needed.

As far as replacement, generally they aren't replaced unless the parts become difficult to obtain or the unit becomes a "problem child" that is costing more in maintenance and parts than replacement... Of course, if a substation is being rebuilt anyway then that may be a different issue.

 

[PowerGrad]

Thanks for your reply overvoltage.Yes I am talking about disconnect switches. Our main criteria are as follows: insulators in a bad state, eroded contacts and current path, mechanism not working or motorised operation not functioning. How does that sound to you?

Yes the maintenance and spare parts issue might be the reason for some specific models being requested for replacement. For example, does anyone have experience of a GE RB3 disconnector?

Does anyone know what lifespan can be achieved with disconnectors?

All comments much appreciated.

 

[PowerGrad]

Oh also from looking at fault data and elsewhere I am thinking that the main faults on a disconnector are:
1)broken insulators
2)contacts not making well - eroded etc
3)hot spots
4)mechanism not functioning well

 

[Overvoltage]

Seems reasonable to me.