Measurement Over The Broken Delta - Woodward HighPROTEC MRA4 Manual Del Usuario

2.6.4.2

Measurement Over the Broken Delta

Elemento de Ejemplo
20000 V
L1 L2 L3
V̲ L 12
V̲ L 23
V̲ L 31
After the voltage inputs have been connected correctly the residual voltage is measured
with the following setting:
• »VG[x] . Fuente VG« = «medido»
The broken delta is usually realized such that the RMS value of the residual voltage in
case of a 1p ground fault equals the RMS value of the phase-to-phase voltage.
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 . TVT sec« and »VT . TVT 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 med = 1.0⋅Vn
Example: For the voltage transformer data shown in the diagram above (secondary
voltage = 100 V / 3), the result is:
• VG med = 1.0⋅Vn = 100 V
MRA4-3.7-ES-MAN
100 V
3
3
V̲ L 1
V̲ L 2
V̲ L 3
2.6.4.2 Measurement Over the Broken Delta
Par. cam./VT
Nombre Valor
VT pri 20000
VT sec 100
VT con Fase a masa
TVT pri 20000
TVT sec 100
Sinc V L12
VG̲ '
MRA4
Unidad
V
V
V
V
X?.
1
2
3
4
5
6
da [e]
7
dn [n]
8
2 Hardware
VL1/VL12
VL2/VL23
VL3/VL31
VG
133