Introduction
1.3 Characteristics
SIPROTEC, 7UM62, Manual
C53000-G1176-C149-7, Release date 03.2010
31
100 % Stator Earth Fault Protection with 20 Hz Bias Voltage
• Evaluation of the 20 Hz measurement (7XT33 and 7XT34).
• Warning and trip stage R< and R<<.
• Trip stage with earth current.
• High sensitivity also with large stator earth capacitances.
Earth Current Protection B
• For various applications such as stator current supervision, any kind of earth current supervision and shaft
current protection for detecting faults in bearings .
• Selection of different measurement methods possible (fundamental harmonic, 3rd harmonics and 1st and
3rd harmonics)
• High sensitivity (above 0.5 mA) by selected FIR filter
Interturn Fault Protection
• Detection of interturn faults in generators by measuring the displacement voltage opposite the generator
starpoint
• High sensitivity (above 0.3 V)
• Suppression of disturbances by selected FIR filter
Rotor Earth Fault Protection (R, fn)
• 100 % protection for the entire excitation circuit.
• Symmetrical capacitive coupling of a system-frequency AC voltage into the excitation circuit
• with consideration of operational earth impedances and brush resistances
• Calculation of the fault resistance from the total impedance
• Alarm stage and tripping stage directly adjustable in Ohms (rotor-earth resistance)
• Measuring circuit supervision with alarm output.
Sensitive Rotor Earth Fault Protection with 1 to 3 Hz Square Wave Voltage Injection
• Evaluation of the 1 to 3 Hz square-wave voltage injected into the rotor circuit (7XT71).
• Warning and trip stage R< and R<<.
• High sensitivity (max. 80 KΩ).
• Integrated test function.
Motor Starting Time Supervision
• Inverse-time tripping based on an evaluation of the motor starting current
• Definite time delay with blocked rotor.
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