HV Line Test

How to test an over head 11Kv line when tripped by ( earth signal )

I am assuming you mean a tree (or similar) has contacted the overhead 11kV line and caused the substation protection to operate disconnecting the line, and you are after a way of determining if the phase to ground fault (tree, etc) is still there (and where on the line it is) before closing the substation breaker.

The simplest way for such a small length of line is by visual inspection in conjunction with proper tree grooming (to reduce the risk of tree to line faults occurring). Visual inspection will also pick up fallen overhead lines due to such things as vehicle verses pole (ie- pole supporting 11kV line has been knocked down and 11kV line is on ground). This is basic transmission line procedure world-wide.

There are more complicated and expensive methods to transmit a signal down the line and measure reflectance, etc to pin-point the location of the fault, but you are still going to need to send someone out for a visual inspection and removal of the fault. Use of a recloser to attempt to 'blow' the fault clear of the line is a possibility but won't help if the 11kV line is lying on the ground (it also puts strain on the line).

Smart pulsecloser switchgear is available, but I don't think the distance to fault feature is available just yet.

http://www.sandc.com/products/intellirupter/default.asp

Dear Jack.

Thanks so much for your attention in respons to my problem.

Acually i send som one to check the lins by visual inspection but I didn't found any fault line and with more inspection for the columns one by one I fount one insulating carrier( porcelain) was broken and the line attached to the column.

thank u again for the link.

best regard.