9424200994 Rev N 105Table 37. Polarization SettingsSetting Range/Purpose Default67N PolarizationMethodIG Use Zero Sequence Current PolarizationIG/Q/VQ Use Negative Sequence PolarizationV Use Zero Sequence PolarizationIG/Q/V* Use all three polarization methodsIG/Q* Use IG and Q polarization methodsIG/V* Use IG and V polarization methodsQ/V* Use Q and V polarization methodsZero-SequenceModeVOIN Calculated Zero Sequence Volt, Calculated Zero Sequence CurrentVOINVOIG Calculated Zero Sequence Volt, Measured Ground CurrentVXIN Measured 3V0-VX, Calculated Zero Sequence CurrentVXIG Measured 3V0-VX, Measured Ground Current* Modes IG/Q/V, IG/Q, IG/V, and Q/V are logical ORs of Modes IG, Q, and V and are used to set up dualor possibly triple polarization techniques for the neutral elements. Thus, if more than one directionalsupervision element is enabled, any element can enable tripping if the appropriate forward or reversedirectional decision is made.Maximum Torque Angle and Directional TestsThe directional algorithm requires a user settable maximum torque angle (MTA). There is an MTA settingfor positive-sequence calculations, an MTA setting for negative-sequence calculations, and an MTAsetting for zero-sequence calculations. These settings are separate from the power line impedanceparameters (Z 1 and Z 0 used for distance to fault calculations) because some applications require apolarizing MTA different from the "distance to fault" line impedance angle.Each MTA can be set over the range of 0 to 90 degrees (I lag E) in 1 degree steps. These parameters areinput into the BE1-11g using BESTCOMSPlus. Open the System Parameters, Power System tree branch.A fault current is considered to be in a forward direction when the sequence current, after being offset bythe line angle, is in phase with the same sequence voltage. The forward direction zone extends forapproximately ±90° from the nominal line angle. A similar argument applies for the reverse direction withthe current 180° out of phase from the voltage. The angle of Z1 is used during positive and negative-sequence directional test. Likewise, the angle of Z0 is used during the zero-sequence directional test.Angle compensation is not required for current polarization since the polarizing quantity IG is inherentlycompensated.Note that (not forward) does not necessarily imply reverse. Sufficient current and voltage must be presentto declare direction. Internally, the BE1-11g also uses several constant limits to determine if the systemlevels are adequate to perform reliable directional tests and set directional bits. See Table 38.Table 38. Internal ConstantsInternal Constant Purpose ValuePositive-SequenceCurrentMinimum I1 current threshold for Positive-Sequence test 0.50 A for5A CTsand 0.1 Afor 1A CTsZero-Sequence Current Minimum 3I0 current threshold for Current Polarization test 0.25 A for5A CTsand 0.05 Afor 1A CTsBE1-11g Directional Overcurrent (67) Protection
