Tan Δ (Power Factor) Measurement - GE Kelman DGA 900 Plus Installation & Commissioning Manual

If the C1% measurement is above 5% after these checks, please contact GE customer
support team.
10.4.4 C.4
To verify that the wiring is correct and that initial alarms levels are appropriate for the
system with instantaneous Tan δ measurements:
▪
Select BMT > Configuration as shown in Figure 10-24 to verify the 'Exponential
Moving Average Configuration'. Ensure that:
− 'Daily Moving Average Enable' is Off
− 'Moving Average Factor Phase Angle' is 100 (factory default is 10000)
Figure 10-24: Exponential Moving Average Configuration
▪
Select BMT > Live Measurement as shown in Figure 10-25 to verify the 'Measured
Phase Angle'. Ensure that:
− the measured angles are within 2 degrees of the expected angles. If the phase
angles are measuring more than 2 degrees, contact GE Technical Support for
further guidance. If applicable, check the same on secondary bushings.
− the imbalance (polar plot amplitude) for tan δ is less than 120%. If the tan δ is
more than 120%, the alarm limit should be adjusted. The alarm is recommended
to be set at 50% above the highest measurement. If applicable, check the same on
secondary bushings.
Figure 10-25: Measured Phase Angle
To change the Polar Plot PF % alarms:
▪
Select Alarm > Bushing Alarm Configuration > Primary Polar Plot PF% as shown
in Figure 10-26 to adjust the alarm as required for both Primary and Secondary
sources, High-High and High limits.
MA-041 – DGA 900 Plus - Installation & Commissioning Manual - Rev 1.1
Tan δ (Power Factor) Measurement
4-Mar-22 Page 89 of 99