Maximum Torque Angle And Directional Tests - Basler BE1-11g Instruction Manual

9424200994 Rev U
Setting
CT Source CT Circuit 1 or CT Circuit 2
67N Polarization
IG/Q/V*
Method
IG/Q*
IG/V*
VOIN
VOIG
Zero-Sequence
Mode
VXIN
VXIG
* 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 dual
or possibly triple polarization techniques for the neutral elements. Thus, if more than one directional
supervision element is enabled, any element can enable tripping if the appropriate forward or reverse
directional decision is made.

Maximum Torque Angle and Directional Tests

The directional algorithm requires a user settable maximum torque angle (MTA). There is an MTA setting
for positive-sequence calculations, an MTA setting for negative-sequence calculations, and an MTA
setting for zero-sequence calculations. These settings are separate from the power line impedance
parameters (Z and Z used for distance to fault calculations) because some applications require a
1 0
polarizing 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 are
input 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 by
the line angle, is in phase with the same sequence voltage. The forward direction zone extends for
approximately ±90° from the nominal line angle. A similar argument applies for the reverse direction with
the 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 inherently
compensated.
Note that (not forward) does not necessarily imply reverse. Sufficient current and voltage must be present
to declare direction. Internally, the BE1-11g also uses several constant limits to determine if the system
levels are adequate to perform reliable directional tests and set directional bits. See Table 42.
Internal Constant
Positive-Sequence
Current
Zero-Sequence Current
Ground current (IG)
BE1-11g
Table 41. Polarization Settings
IG Use Zero Sequence Current Polarization
Q Use Negative Sequence Polarization
V Use Zero Sequence Polarization
Use all three polarization methods
Use IG and Q polarization methods
Use IG and V polarization methods
Q/V* Use Q and V polarization methods
Calculated Zero Sequence Volt, Calculated Zero Sequence Current
Calculated Zero Sequence Volt, Measured Ground Current
Measured 3V0-VX, Calculated Zero Sequence Current
Measured 3V0-VX, Measured Ground Current
Table 42. Internal Constants
Minimum I1 current threshold for Positive-
Sequence test
Minimum 3I0 current threshold for Current
Polarization test
Minimum Ground (IG) current threshold for
Current Polarization test
Range/Purpose
Purpose
Directional Overcurrent (67) Protection
115
Default
CT
Circuit 1
IG/Q/V
VOIN
Value
0.50 A for 5A CTs and
0.1 A for 1A CTs
0.25 A for 5A CTs and
0.05 A for 1A CTs
0.50 A for 5A CTs and
0.1 A for 1A CTs