High Voltage in Hi-Z Protection ?
High Voltage in Hi-Z Protection ?
(OP)
Hi All,
In Hi-Z diff Protn we calculate Vpeak and if its greater than the Impulse Voltage rating of the TRM we go for Non-linear Resistor.
I wanted to the physics behind , How High voltage is generated in Hi-Z differential Protection during internal faults? Can anyone explain?
Thank you in advance.
Yeruk
In Hi-Z diff Protn we calculate Vpeak and if its greater than the Impulse Voltage rating of the TRM we go for Non-linear Resistor.
I wanted to the physics behind , How High voltage is generated in Hi-Z differential Protection during internal faults? Can anyone explain?
Thank you in advance.
Yeruk






RE: High Voltage in Hi-Z Protection ?
RE: High Voltage in Hi-Z Protection ?
I agree partially . when there is internal fault due to imbalance of current Voltage is developed but why is it "High after the instance of Fault" and later settles. in other words There is an Impulse later it settles ? I am not completely convinced.
Thanks in advance
Yeruk
RE: High Voltage in Hi-Z Protection ?
An internal fault in a switchboard fitted with bus zone prot (HiZ)
-maximum fault current available at the switchboard(amps)
-causes x amps in the CT summated secondary circuit because it's coming in but not going out.
The x amps is flowing through the resistor and the prot relay.
x amps times whatever ohms is volts (lots usually).
hence the metrosil or whoever''s Non-linear resistor to clamp the volts
RE: High Voltage in Hi-Z Protection ?