Siemens 7SG164 Ohmega 400 Series Manual page 111

4.4 Power Swing Detector Tests.
Power Swing Detector
Power swing impedance based detector consists of two mho or quad zones. The outer zone is a replica of the
inner zone multiplied by a specific factor set by a user. Before starting the tests, ensure that one of the relay LEDs
is mapped to the Power Swing Alarm.
4.4.1 Power Swing Impedance Reach.
Apply a balanced three-phase condition with the impedance below the impedance setting of the inner zone.
Gradually increase the impedance until the Power Swing Alarm operates. Record the minimum reach of the power
swing detector, i.e. the reach of the inner zone. This should be repeated for the inner reverse reach where
applicable.
Inner Zone Fwd Reach
Inner Zone Rev Reach
Element
Inner Zone Forward Reach
Inner Zone Forward Reach
Ensure that the percentage error does not exceed ± 5%
The outer reach of the Power Swing Detector zone is set by a multiplying factor. The actual outer reach is the
inner reach multiplied by the PSD Outer multiplier.
PSD Outer multiplier
Outer Zone Fwd Reach
Outer Zone Rev Reach
Apply a balanced three-phase condition with the impedance above the impedance setting of the outer zone.
Gradually decrease the impedance until the Power Swing Alarm operates. Record the maximum reach of the
power swing detector, i.e. the reach of the outer zone. This should be repeated for the outer reverse reach where
applicable.
Element
Outer Zone Forward Reach
Outer Zone Forward Reach
Ensure that the percentage error does not exceed ± 5%
©2010 Siemens Protection Devices Limited
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Measured Impedance
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Measured Impedance
7SG16 Ohmega 402 60 Commissioning
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Chapter 9 Page 13 of 19
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