Minimum impedance protection & voltage balance protection

[speedtronic]

What are minimum impedance protection & voltage balance protection for Sync. Genarators (turbo/hydro)?
Please explain

 

[Guest123]

Hi mate.

This is what I think - Impedance protection for a "sync" generator is to protect the other generators in the system from damage. If the field current drops in one geney and the magnetic connection between stator and rotor disappears then the rotor speed will increase so the inductive KVAr that it supplies to the system reverses and becomes negative so instead of supplying KVAr its is taking it away and is running "asynchronously".

Also the armature current will increase where as the KW output will decrease therefore an impedance protection relay would "trip" the geney and stop a complete failiure of everything.

By voltage balance protection I assume you mean on the output side and you would install an AVR - Automatic Voltage Regulator, to detect any surges in power supplied and disconnect the geney from the system. This would also work for a drop in power supplied by increasing the engine speed to compensate.

I hope that this makes sense to you.

Regards.