REG 670 : 50 Hz : Raxle=0
3 0 mA 4 0 mA 50 mA 70 mA 10 0 mA 150 mA 2 0 0mA 3 0 0 mA
IEC06000445 V1 EN-US
Figure 385: Sensitivity dependence of winding capacitance at different current settings
The undervoltage stage of the General current and voltage protection (CVGAPC) can be used to
monitor the injection voltage and give alarm if the injection voltage is absent. It shall be set to
80% of the rated value of the rated value of the injected voltage with a time delay of about 10 s.
An additional instance of the General current and voltage protection (CVGAPC) can be used to
provide a third non-directional overcurrent stage which can be used to detect ground faults on the
AC side of the rectifier in case of a static excitation system. It shall be set to operate when the
magnitude of the injected current into the rotor circuit exceeds 125 mA and with a delay of 5 s. As
the CT in RXTTE4 has a ratio 10:1 the current measured by the IED will be at least 1.25 A for this
fault.
11.2.3 Technical data
SEMOD175177-1 v1
SEMOD175176-2 v5
Table 415: Rotor ground fault protection (64R) based on General current and voltage protection (CVGAPC) and
RXTTE4
Function Range or value
For machines with:
• rated field voltage up to 350 V DC
• static exciter with rated
supply voltage up to
700 V 50/60 Hz
Supply voltage 120 or 230 V 50/60 Hz
Table continues on next page
Section 11 1MRK 502 066-UUS B
Multipurpose protection
718
Technical manual
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