ABB Relion 670 series, Technical Manual

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7.13.8.1 The injection unit REX060
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In
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Backplane
Front-plate
Back view Front view
Power
connector
IED and
Injection
connectors
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Top view
HMI with logic
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18 18
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X11 X61
X81
Injection switch
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X62 X82
Keylock
LED
Injection LED
IEC11000015-1-en.vsd
IEC11000015 V1 EN-US
Figure 215: Injection unit REX060
The REX060 unit is a common unit that can be configured for either rotor or stator ground fault
protection, or for both. The REX060 have separate modules for rotor and stator protection. The
REX060 generate 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 voltage and currents are measured by the unit and amplified, resulting in
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, preferably in the same cubicle.
For the Sensitive rotor earth fault protection, there are some settings necessary for REX060:
• System frequency: 50/60 Hz
• Injected frequency for rotor circuit injection that is settable within the range 75 – 250 Hz with
1 Hz step.
• Gain factor in four steps
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 signal, connected to IED,
is activated. Also other errors in the injection circuit will initiate a binary signal to IED for blocking
of the function.
Rotor injection output is protected against high voltages by a relay blocking the injection circuit.
This blocking remains active by stored status in non-volatile memory.
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.
7.13.8.2 Rotor Earth Fault Protection function
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The injection to the rotor is schematically shown in figure 216 .
Section 7 1MRK 502 066-UUS B
Impedance protection
402
Technical manual