Resetting Overvoltage - ABB Relion 670 series Operation Manual

Section 8
REX060 injection unit LHMI
Table 18:
8.1.5.5

Resetting overvoltage

Stator and rotor injection output is protected against voltages exceeding maximum operating
range (10% of rated VT/DT) by a relay blocking the injection circuit. This blocking is controlled
by measuring the stator and/or rotor voltage, and remains blocked until manually reset. The
blocking remains in the non-volatile memory when the IED is powered off.
Overvoltage blocking is indicated by a symbol shown in Table 16.
Resetting procedure:
1. Power off the REX060.
2. Press and hold the C and Key-lock buttons.
3. Power on the REX060 and wait until the status indication
disappears from the display.
4. Release the C and Key-lock buttons.
REX060 stator and rotor overvoltage protection of injection circuit
Both rotor and stator have two levels of protection, injection circuit interruption controlled by
the voltage sense input and a fuse for over-current protection. The voltage controlled
interruption, overvoltage, will normally occur prior to interruption by fuse and the reset
sequence is described above. A blown fuse requires module disassembling to replace the fuse
(F 4 A 250 V for stator and F 160 mA 250 V for rotor). However, if this occurs it is recommended
to identify the reason for the over-current and take necessary actions to reduce the current
before restarting the unit. The problem must be outside the injection unit since this unit
cannot provide enough energy to blow the fuse.
REX062 input protection
REX062 limits overvoltage by a varistor at the injection output to stator. Normally , REX060 will
interrupt the injection circuit in case of excessive over-current in the injection chain. Fuse
within REX062 is an additional protection in case of failure within REX062 during over-voltage
condition.
A blown REX062 fuse requires a module disassembling to replace the fuse (F 6.3 A 250 V).
However, if this occurs it is recommended to identify the reason for the over-current and do
needed actions to reduce the current.
76
Stator gain
UmaxEF [V]
240
200
160
up to 120
Note
Default value
Over-voltage (symbol)
1MRK 500 127-UEN D
GUID-656B534F-3F83-4B35-8020-F9875FF82DED v1
670 series
Operation manual