of the capability curve of the transformer/generator. Setting should be above the knee-point when the characteristic starts to be straight on the high side.XLeakage: The transformer leakage reactance on which the compensation of voltagemeasurement with load current is based. The setting shall be the transformer leakreactance in primary ohms. If no current compensation is used (mostly the case) the settingis not used.t_TripPulse: The length of the trip pulse. Normally the final trip pulse is decided by thetrip function block. A typical pulse length can be 50 ms.CurveType: Selection of the curve type for the inverse delay. The IEEE curves or tailormade curve can be selected depending of which one matches the capability curve best.TDforIEEECurve: The time constant for the inverse characteristic. Select the one givingthe best match to the transformer capability.t_CooolingK: The cooling time constant giving the reset time when voltages drops belowthe set value. Shall be set above the cooling time constant of the transformer. The defaultvalue is recommended to be used if the constant is not known.t_MinTripDelay: The operating times at voltages higher than the set Pickup2. The settingshall match capabilities on these high voltages. Typical setting can be 1-10 second.t_MaxTripDelay: For overvoltages close to the set value times can be extremely long if ahigh K time constant is used. A maximum time can then be set to cut the longest times.Typical settings are 1800-3600 seconds (30-60 minutes)AlarmPickup: Setting of the alarm level in percentage of the set trip level. The alarm levelis normally set at around 98% of the trip level.tAlarm: Setting of the time to alarm is given from when the alarm level has been reached.Typical setting is 5 seconds.10.4.3.3 Service value reportA number of internal parameters are available as service values for use at commissioningand during service. Remaining time to trip (in seconds) TMTOTRIP, flux densityVPERHZ, internal thermal content in percentage of trip value THERMSTA. The valuesare available at local HMI, Substation SAsystem and PCM600.10.4.3.4 Setting exampleSufficient information about the overexcitation capability of the protected object(s) mustbe available when making the settings. The most complete information is given in anoverexcitation capability diagram as shown in figure 292.Section 10 1MRK 506 369-UUS -Voltage protection584 Line distance protection REL670 2.2 ANSIApplication manual
