Toshiba GR-200-5 Instruction Manual

Also see for GR 200 Series: Instruction manual Instruction manual Instruction manual Instruction manual Instruction manual

6F2T0207 (0.01)GRE200 (5,6)- 198 -As for an intermittent fault (the former in the figure), the time counter will not reach thetrip level. In the other words, the operation of the OVN1 element is paralyzed in the reset timeset by [TOVN1R].If a series of fault occurs repeatedly (the latter in the figure), and if the value of the timecounter reaches at trip level, the OVN1 element will issue a trip command after a certain delay.After issuing the trip command, if a series of fault completely disappears after issuing the tripcommand, the value of the time counter will be expired after the reset time [TOVN1R].When the user requires resetting the operation of the OVN1 element immediately, settingzero for the settings [TOVN1R] is needed. Consequently, when a voltage falls below the resetthreshold (drop-off), the operation of the OVN1 element is reset promptly.Figure 2.18-3 Faults occurrences and reset operation when IDMT being applied2.18.4 Miscellaneous functions(i) OVN operation blocked by the occurrence of VT failureBlocking the OVN function may be required when a failure in the voltage transformer occurs.In this case, the user shall set Block for scheme switch [OVN1-VTFBlk]. Non (as a default) isset for scheme switch [OVN1-VTFBlk] in order that the OVN function is not blocked by thefailure.Condition fault occurrenceFault observation by the relayIssue of trip commandTrip levelIncrimination of time countercorresponding to the faultduration.T1T1: Resetting time set by the userT2: Actual resetting time in the relay operationT3: Time gap between fault occurrence and relay start timeTrippingT1 T1 T1T2T2T3Intermittent faultSeries faultsRelay operation resetReset of time counterIncrement process in timecounterValue maintenance of time counter