I would like to have some feedbacks on CB,s used in SVC,s in steel companies. we had a CB failure(explosion) in a 2nd harmonic filter.(33 KV CB).we are recommended to use 72.5 kv CB,s for all 2nd ,3th ,4th and 5th harmonic filters.The questions are:1-Are CB,s rated 50 HZ suitable for switching...
I would like to draw your attension to following points.
1-Due to property problems with substation neighbours in 3 sides ,we can,t extend the grid outside the fence.
2-As a fence there are actualy prefabricated concrete walls with 2.5 m height around the sub. but some mesh type metalic guards...
I would like to have some feedbacks on CB,s used in SVC,s in steel companies. we had a CB failure(explosion) in a 2nd harmonic filter.(33 KV CB).we are recommended to use 72.5 kv CB,s for all 2nd ,3th ,4th and 5th harmonic filters.
The questions are:
1-Are CB,s rated 50 HZ suitable for switching...
we are invoved in designing ground grid for a 63/20 Kv sub.(area: 120*80 sqm).The fence can not be included within ground grid area.the outer ground wire is 1 m inside the fence. our reccomendation is to isolate the fence from the grid and earth it seperatly but our client wants to connect the...
Have you choosed prpoper shock time ? this can affect the amount of copper cosiderably. How about unsymmetrical grid design, have you tried it?Isolating fence may help your copper saving depending sub. area.
Hi.
Although relay manufactuerers claim their distance relays are capable of protecting short lines ( less than 10 Km) effectively provided SIR is less than 30 .
It is also claimed that CVT transients have no major effect on the operation of relay.
Meanwhile most of electric design engineers and...
Hi.
The VT manufactuerer also is,nt agree with sizing a bigger fuse as Scottf says.
We are going to reconnect second windings in open delta and insert damping resistors .
Although i am not still sure that the low value of cpacitance presents in switchgear busbars plus 250 m cable and 2 OHL...
Hi.
As far as subtation operators say it happens when CB,s trip
or close. no report during normal operation.
i would like to know what would happen if there were no fuse on primary side of VT.
best regards
Hi
The main trans. is YNd1 and there is a grounding trans. ZNyn5
connected in the vicinity of main trans.(2 20KV incoming feeders are in parallel mode)
there is something else ,i am not sure about it.
is there any inrush current for a VT during switching ,especialy when vt has a low burden...
dear freinds.
There are some VT primary fuse burnt outs in the newly energized 24 Kv metal clad switchgear.there is no short circuit in vt secondary side.it mostly happens in the time of swiching of 132/20 KV transformers.Two 20 KV outgoing feeders supply 20KV overhead lines.
vt,s have 1/4 of...
