Setting Notes - Siemens SIPROTEC 7UM62 Manual

2.35 Sensitive Rotor Earth Fault Protection with 1 to 3 Hz Square Wave Voltage Injection (ANSI 64R - 1 to 3 Hz)
2.35.2

Setting Notes

General
Sensitive rotor earth fault protection is only effective and available if configured at address 161 REF 1-3Hz to
Enabled.
It must also be ensured that the measuring transducer inputs TD1 and TD2 are not used for any other function.
Address 6101 REF 1-3Hz serves to switch the function ON or OFF or to block only the trip command (Block
relay).
The delivery setting of the measuring transducers TD1 and TD2 to 10 V must not be changed (see tables 3-18
and 3-19).
Pickup Values
Since the protection calculates the ohmic rotor-earth resistance directly from the values of the applied bias volt-
age, the series resistor and the flowing earth current, the thresholds for the warning stage (6102 RE< WARN)
and for the trip stage (6103 RE<< TRIP) can be set directly as resistance values. The default settings (RE<
WARN = 40 kΩ and RE<< TRIP = 5 kΩ) are sufficient for the majority of cases. These values can be changed
depending on the insulation resistance and the coolant. Care must be taken to allow a sufficient margin
between the setting value and the actual insulation resistance.
As interference from the excitation system cannot be excluded, the setting for the warning stage is finally es-
tablished during primary tests.
Time Delays
The time delay for the warning stage 6104 T-WARN-RE< is usually set to approximately 10 s, and the delay for
the trip stage 6105 T-TRIP-RE<< to approximately 1 s. The set times are additional time delays not including
the operating times (measuring time, drop-out time) of the protective function.
Monitoring Functions
The setting value of the measuring circuit monitoring (6106 Qc <) is defined during the primary test. For this
purpose the operational measured value (Qc) is read out and half of this value is set. If the charge measured
is too low, monitoring cannot be effective. The parameter Qc < should in that case be set to 0 mAs. No fault
indication will be issued in this case.
No setting is required if the external test is done using the test resistor 7XR6004 (3.3 kΩ). If a different resistor
is to be used, its resistance must be set as an advanced parameter TEST RESISTOR (only via the DIGSI com-
munication software) at address 6107A.
SIPROTEC, 7UM62, Manual
C53000-G1176-C149-7, Release date 03.2010
Functions
249