The injection unit REX060
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Backplane
Front-plate
Back view Front view
Power
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IED and
Injection
connectors
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Top view
HMI with logic
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X11 X61
X81
Injection switch
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Keylock
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Injection LED
IEC11000015-1-en.vsd
IEC11000015 V1 EN-US
Figure 223: Injection unit REX060
The REX060 unit is a common unit with it's own built-in Power Supply Module (PSM) of the same
type as used in the IED that can be equipped for either rotor or stator ground fault protection, or
for both. The REX060 has specific injection modules for rotor and stator protection. The REX060
generates square wave signals, where one is used for injection to the stator neutral point and the
other to the field winding circuit (rotor circuit), if configured for both stator and rotor protection.
The injected voltages and currents are measured by the unit and amplified, giving voltage signals
both for the injected voltage and current, and adapted to the analogue inputs of IED. The injection
unit REX060 shall be located close to the IED.
For the stator ground fault protection, there are some settings necessary for REX060:
• System frequency: 50/60 Hz
• Injected frequency for stator neutral point is settable in 1 Hz steps 50 – 250 Hz.
• VT/DT maximum fundamental frequency voltage during ground fault in the stator winding
REX060 will also continuously check the measured signal for detection of saturation which could
cause error in the evaluation in IED. If saturation level is reached, a binary output contact is
activated, which is connected to IED. Also other errors in injection will activate another output
contact to IED for blocking the function.
Stator injection output is protected against voltages exceeding maximum operating range (10%
of rated VT/DT) by a relay blocking the injection circuit. This blocking remains blocked by stored
status in non-volatile memory. Note REX060 is designed to cope with such voltages of up to 120V.
When optional REX062 resistor unit is used, REX060 can cope with voltages of up to 240V at
injection point.
The output is also protected by a fuse. If this fuse is blown, it is caused by external voltage source,
since the injection unit cannot provide enough energy to blow this fuse.
Refer to the Hardware section in this manual for a detailed description of REX060.
7.14.8.2 Generator system grounding methods
GUID-3F1DF455-1F11-4D4A-820B-FC3376F2EAB5 v3
There are several principles for system grounding of synchronous generators. The choice of
grounding method depends on different factors:
1MRK 502 066-UUS B Section 7
Impedance protection
417
Technical manual
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