1.3 Features
9
7UM62 Manual
C53000-G1176-C149-3
Impedance
Protection
•
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.
Out-of-Step
Protection
•
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.
Undervoltage
Protection
•
Two undervoltage elements, measuring positive sequence voltage.
•
Additional stage with settable, voltage-dependent time characteristic.
Overvoltage
Protection
•
Two-stage overvoltage measurement, evaluation of the highest of the three
voltages;
•
Optionally with phase-to-phase voltages or with phase-to-earth voltages.
Frequency
Protection
•
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.
Overexcitation
Protection
•
Calculation of the ratio U/f;
•
Adjustable warning and tripping stage;
•
Standard characteristic or either optional characteristic selectable for calculation of
the thermal stress.
Rate-of-Frequency-
Change Protection
•
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.
Jump of Voltage
Vector
•
Sensitive phase jump detection to be used for network disconnection.
90–%–Stator Earth
Fault Protection
•
For machines in unit connection and for machines directly connected to busbars;
