Pre-insertion resistors 1

[protkid1]

Is it possible to use Pre-insertion resistors in a 132 kV GIS CB.
The switching duty is for energizing a shunt reactor supplying a 100 km long 132 kV cable. The studies indicate a huge DC offset without current zeroes for approx 1.5 sec. Inserting a resistance can decay the DC component faster.

Alternatively is it possible to employ point of wave switching in case the GIS CBs are gangue operated ( not capable of single pole switching)?

 

[Bronzeado]

Dear protkid1,

I think it will be possible to employ "point on wave" switching by just calibrating mechanically the breaker to close at the correct time. However, I recommend to talk to the manufacturer in order evaluate not only the closing aspects.


Best Regards,

Herivelto S. Bronzeado
Brasília, Brazil

http://www.linkedin.com/profile/view?id=46319837&trk=tab_pro

 

[Tofeil]

to employ point of wave switching, you need circuit breaker with switch-synchronous relay. And there is not need pre-insertion resistor.

 

[odlanor]

see
point-on-wave synchronism relay- alstom grid

 

[protkid1]

Could not understand one target condition in the attached doc:
De-energizing shunt reactors ---opening operation ---target is "medium arcing time"..
Is this another way of saying that it will open after the initial dc offset is finished (i.e. 1.5 secs approx.) ?

Thanks friends !! The solutions are under discussion.

 

[odlanor]

This was our application:
The line circuit breakers to be used for a 500kV EHV transmission line has no synchronism mechanism (ie, the closing of the contacts is done in
any instant in the waveform of the voltage).
Shunt reactor compensation line is relatively large;-in the condition with little studied simultaneous energization(A B C) together (row + reactor compensation ) introduces a DC component in different phases of the power grid.
Thus, there are large swings in machines at power plants nearby.
The oscillations caused by DC component in the network arising from AC power (+ line reactor shunt compensation) was considerably reduced by timing mechanism (ie, the closing of the contacts would be done when the voltage passes through peak).