5-202 G30 Generator Protection System GE Multilin5.6 GROUPED ELEMENTS 5 SETTINGS5Figure 5–87: VOLTS PER HERTZ SCHEME LOGICThe element has a linear reset characteristic. The reset time can be programmed to match the cooling characteristics of theprotected equipment. The element will fully reset from the trip threshold in VOLTS/HZ T-RESET seconds. The V/Hz elementmay be used as an instantaneous element with no intentional time delay or as a Definite or Inverse timed element.The characteristics of the inverse curves are shown below.DEFINITE TIME:For the definite time curve, T(sec.) = TD multiplier. For example, setting the TD multiplier to 20 results a time delay of 20seconds to operate when above the Volts/Hz pickup setting. Instantaneous operation can be obtained the same way by set-ting the TD multiplier to “0”.INVERSE CURVE A:The curve for the volts/hertz inverse curve A shape is derived from the formula:(EQ 5.49)where: T = Operating TimeTDM = Time Delay Multiplier (delay in seconds)V = fundamental RMS value of voltage (pu)F = frequency of voltage signal (pu)Pickup = volts-per-hertz pickup setpoint (pu)SETTINGSETTINGSFLEXLOGIC OPERANDSSETTINGSETTINGVOLTS/HZ 1FUNCTION: VOLTS / HZ 1TD MULTIPLIER:VOLTS / HZ 1T-RESET:VOLTS / HZ 1CURVE:VOLTS / HZ 1PICKUP:VOLTS PER HERTZ 1 PKPVOLTS PER HERTZ 1 DPOVOLTS PER HERTZ 1 OPVOLTS/HZ 1 BLOCK:Off = 0Enabled = 1VOLTS/HZ 1SOURCE:VOLT / HzRUNANDtV/Hz828003A7.CDRVOLTS / HZ 1VOLTAGE MODE:T TDMVF---- Pickup⁄ 21–------------------------------------------------- when VF---- Pickup>=
