Entec ETMFC610 - Ground Directional Controls (67 G)

Multi-Function Control ETMFC610 http://www.entecene.co.kr
263
EN
HANCED
TEC
HNOLOGY
GROUP # / DIRECTION / PHASE / Block OC
Range
NO, YES
Default
NO
Step
~
Select whether to trip when polarizing voltage is dropped below
minimum polarizing voltage set.
NO : Trip on over current element.
YES : No trip on over current element.
8.3.2. Ground Directional Controls (67G)
Zero phase voltage 3V
0
provides ground control direction in power system. Ground direction is
determined by comparing zero phase voltage (3V
0
) and zero phase current(I
0
). If an angle from
zero phase voltage to zero phase current is within

90˚ based on Maximum Torque Angle, it is
forward direction, otherwise, reverse direction. Maximum Torque Angle is between ∠0˚ and ∠359
˚. Initial set value of max torque angle is set for ∠135˚ leading compared with Zero sequence
voltage(V
0
).
Polarized voltage drops Min. polarized voltage, ground direction control is cancelled and ground
fault(fault indication type) and ground overcurrent(protection type) are not detected. On the other
hand, if ground direction control is set for ‘NONE’, ground fault and ground overcurrent are
detected regardless of direction.
Ground direction control type is set to detect ground fault and ground overcurrent. Depending on
control type, ground fault and ground overcurrent are detected or is not detected.
Following figure shows phasor graph of zero phase current direction polarity in complex plane.
[PHASE]
Type: NONE
M.T.A: 60
M.P.V(V1): 0.30
>Block OC: YES
[NO/YES]