Voltage Elements - GE Multilin F650 Instruction Manual

5.4 PROTECTION ELEMENTS
The F650 incorporates the following voltage units:
• Phase undervoltage (27P)
• Phase overvoltage (59P)
• Neutral overvoltage (59NH/59NL)
• Negative sequence overvoltage (47)
• Auxiliary overvoltage (59X)
• Auxiliary undervoltage (27X)
These protection elements can be used in multiple applications, such as:
Undervoltage protection: for induction motor load types, where a voltage dip can cause an increase of the consumed
current. Unit 27P (phase undervoltage) can be used to issue a trip or an alarm.
Transfer Schemes: in the event of an undervoltage condition, we can use Unit 27P (phase undervoltage) to send a signal
that will transfer load to another power source.
Undervoltage units can be set to operate with definite time or with an inverse time curve. If the unit is set as definite time, it
will operate when voltage remains under the set value during the set period of time. This period can be set from 0s to
900.00 s in steps of 10ms.
These units can also be set as inverse time curves. This family of curves is defined by the following formula:
5
Where:
T = operation time
D = operation time setpoint (delay)
V = voltage applied to the relay
Vpickup = pickup setpoint (Pickup level)
5-64
=
T
−
1
Vpickup
Figure 5–14: INVERSE TIME UNDERVOLTAGE CURVES
F650 Digital Bay Controller
D
V
5 SETPOINTS

5.4.8 VOLTAGE ELEMENTS

GE Multilin