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Impedance
Protection
Out-of-Step
Protection
Undervoltage
Protection
Overvoltage
Protection
Frequency
Protection
Overexcitation
Protection
Rate-of-Frequency-
Change Protection
Jump of Voltage
Vector
90–%–Stator Earth
Fault Protection
7UM62 Manual
C53000-G1176-C149-3
• Phase selective overcurrent fault detection with undervoltage seal-in (for
synchronous machines which take their excitation voltage from the terminal
voltage);
• 2 impedance zones, 1 overreach zone for zone extension (controlled via binary
input), 4 time stages;
• Polygonal tripping characteristics;
• Additional power swing blocking.
• Based on the well-proven impedance measurement method;
• Measurement release by the positive sequence current, and measurement blocking
by the negative sequence current;
• Evaluation of the rate of change of the complex impedance vector;
• Optimum matching to the system conditions by selectable slope of the
characteristic;
• Reliable distinction between the power swing centre being in the system or in the
generator unit area.
• Two undervoltage elements, measuring positive sequence voltage.
• Additional stage with settable, voltage-dependent time characteristic.
• Two-stage overvoltage measurement, evaluation of the highest of the three
voltages;
• Optionally with phase-to-phase voltages or with phase-to-earth voltages.
• Four elements that are independently adjustable for function - underfrequency or
overfrequency, pickup, and time delay;
• Insensitive to harmonics and abrupt phase angle changes;
• Adjustable undervoltage blocking.
• Calculation of the ratio U/f;
• Adjustable warning and tripping stage;
• Standard characteristic or either optional characteristic selectable for calculation of
the thermal stress.
• Monitors whether the frequency exceeds (df/dt>) and/or falls below (df/dt<) a set
limit value, with 4 individually settable limit values or delay times;
• Variable measuring windows;
• Coupling to frequency protection pickup;
• Settable undervoltage threshold.
• Sensitive phase jump detection to be used for network disconnection.
• For machines in unit connection and for machines directly connected to busbars;
1.3 Features
9
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