GE Multilin G30 Generator Protection System 5-1735 SETTINGS 5.6 GROUPED ELEMENTS5These protection elements can be used for a variety of applications such as:• Undervoltage Protection: For voltage sensitive loads, such as induction motors, a drop in voltage increases thedrawn current which may cause dangerous overheating in the motor. The undervoltage protection feature can be usedto either cause a trip or generate an alarm when the voltage drops below a specified voltage setting for a specified timedelay.• Permissive Functions: The undervoltage feature may be used to block the functioning of external devices by operat-ing an output relay when the voltage falls below the specified voltage setting. The undervoltage feature may also beused to block the functioning of other elements through the block feature of those elements.• Source Transfer Schemes: In the event of an undervoltage, a transfer signal may be generated to transfer a loadfrom its normal source to a standby or emergency power source.The undervoltage elements can be programmed to have a definite time delay characteristic. The definite time curve oper-ates when the voltage drops below the pickup level for a specified period of time. The time delay is adjustable from 0 to600.00 seconds in steps of 0.01. The undervoltage elements can also be programmed to have an inverse time delay char-acteristic.The undervoltage delay setting defines the family of curves shown below.(EQ 5.47)where: T = operating timeD = undervoltage delay setting (D = 0.00 operates instantaneously)V = secondary voltage applied to the relayVpickup = pickup levelMESSAGE NEUTRAL OV2 See page 5–177.MESSAGE NEUTRAL OV3 See page 5–177.MESSAGE NEG SEQ OV1 See page 5–178.MESSAGE NEG SEQ OV2 See page 5–178.MESSAGE NEG SEQ OV3 See page 5–178.MESSAGE AUXILIARY UV1 See page 5–179.MESSAGE AUXILIARY UV2 See page 5–179.MESSAGE AUXILIARY OV1 See page 5–180.MESSAGE AUXILIARY OV2 See page 5–180.MESSAGE VOLTS/HZ 1 See page 5–181.MESSAGE VOLTS/HZ 2 See page 5–181.T D1 VV pickup------------------– ----------------------------------=
