Woodward HighPROTEC MRA4 Manual Del Usuario página 132

2 Hardware
2.6.4.1 Calculation from the Three Phase-to-Ground Voltages
Quotient / Scaling Based on Vn
All voltage thresholds of the voltage protection modules are set in units of the nominal
voltage Vn, that is dependent on the settings »VT . VT sec« and »VT . VT pri«.
Example: For the voltage transformer data shown in the diagram above (secondary
voltage 100 V / √3 ̅ ) , we have:
• »VG[x] . VG>« = 1.0⋅Vn = 100 V
Residual Voltage in Case of a 1p Ground (Earth) Fault
• VG calc = √3 ̅ ⋅ Vn
Example: For the voltage transformer data shown in the diagram above (secondary
voltage 100 V / √3 ̅ ) , the result is:
• VG calc = √3 ̅ ⋅ Vn = 173.21 V
132 MRA4 MRA4-3.7-ES-MAN