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DETAILED OPERATION - Section 4
MTS-1700 SERIES OPERATION AND REFERENCE MANUAL 4-39
CU A002 15A
MANTA TEST SYSTEMS
70.0
DEG:V-I IST LINE
C-A
Φ
-
Φ
I3
4.8.2.2
I3-WYE CURRENT MODE. See Section 9.4.4.
4.8.3
Adjusting Prefault, Fault and Postfault Phase Angle
When adjusting phase angle in the fault state and postfault state, the phase angle relative to the prefault
setting is adjusted. This simplifies operation for most testing where phase angle between voltage and current
doesn’t change.
Example:
a) Select static operation mode and, with prefault on, adjust phase angle to 10°. Pressing [FAULT] or
[POSTFAULT], you should also observe that the phase angle is 10° (remember to have adequate
current to get a reading).
b) Press and hold in the [FAULT] button. Note that the phase angle is 10° (same as prefault). Adjust the
phase angle to 20°. Then release the [FAULT] button.
c) Press [POSTFAULT] on (in static mode). Note that the phase angle is 10° (same as prefault). Adjust the
phase angle to 30°. You have now set prefault phase angle=10°, fault phase angle=20°, postfault phase
angle=30°.
d) Press [PREFAULT] on to return to prefault. Adjust the phase angle to 90°.
e) Changing to the fault state and postfault state, you’ll find that the fault phase=100°, and postfault phase
angle=110. This means that the relative phase angle between (fault and prefault) and (fault and postfault)
have not changed.
The implication of this is, if phase angle isn’t required to dynamically change between the voltage and the
current, you only need to set the phase in prefault state. The phase in fault and postfault states will be the
same (i.e. relative values=0). This prevents you from having to set both fault and postfault phase angle to
the proper value every time the prefault phase is changed.
4.8.4
Special Notes
The phase angle measurement has a response time of approx 20ms (100ms when MTS-1720 used in I3-
WYE current mode). When measuring phase angle in dynamic tests, be aware that the reading may not be
accurate if the operate time of the relay is less than this minimum time.
The fault phase angle can be checked before or after a dynamic test by selecting static operation mode,
selecting [PHASE], and pressing [FAULT].
0
I
VC
VB
VA
VCA