11kv BUSBAR PROTECTION

[facetoface]

We have got synch.generator 11KV rating ,ifthe generator is running the earth fault at 11KV busbar is cleared, if not the relay is activated

 

[alehman]

Can you provide more details?
If the earth fault is cleared, that seems normal. What type of relay is it that is activated when the generator is not running?

 

[facetoface]

the 11KV is energized from step up transformer 11/220KV by feadback and the neutral voltage protection is intiated relay , trips from two stages ,U1=17%,U2=40%

 

[davidbeach]

eyadco,

Can you please provide a better discription of what you have and what problem you are having? I really don't know what you are asking.

 

[Alex68]

Some questions to better understand:

What is the group of the step up transformer?
What is the neutral condition without the generator?
Is the generator neutral connected to ground?
The neutral connection is by impedance?
How many connections to ground are there?

Is the activated protection a busbar protection or a transformer protection?
What kind of protection is that?

 

[facetoface]

Again, we have four syn.generator 11KV with neutral resistance to ground and energized power plant through stepup trnasformer 11/220KV , and each generator supplay some auxialry from the B.O.P and when the generator is stopping , we have to energize the auxailary through feedback of 11/220KV
1-4.nos step up transformer is 11/220KV ,31MVA,Zk=12% and neutarl is grounding from the secondary site
2.the neutarl of generator is small resistance 10A/10S
3.the earth resistance of the plant .8 Ohm
4.without gasturbine 11KV system has only earthing through voltage transformer and the natural system capacitances to earth
5-The neutral of busbar is solidy(no neutarl)
6-the protection is at busbar 11KV and is earth fault