PhaseTrakker AP30 Phase Measurement Tips
31
Phase Measurement Tips
Handling “No Match” Readings
The Field Unit reports a “No Match” reading when the difference between the
measured phase angle and the nearest phase angle exceeds the configured De-
gree Tolerance. Possible situations where a reading of “No Match” may be en-
countered:
Situation Action
• Delta-Wye transformer 30° phase shift-----Adjust Phase Shift or
• Field Unit has moved long distance ----------Calibrate Field Unit
• Distant Reference Unit, seasonal drift--------Calibrate Field Unit
• Reference Unit power has changed----------Calibrate Field Unit
• Single-phase transformer ---------------------180° Shift-see tips section
• Other transformer shifts -----------------------Draw phasor diagram
• Interference from adjacent phase------------Reposition Hotstick Unit
• Interference from other sources---------------Reposition Hotstick Unit
For “No Match” readings, it is important to notice the phase angle
reported. “No Match” phase angles can provide clues to understand
the situation and take the appropriate action.
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