ABB RELION REX640 Technical Manual page 1321

Protection and control

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1MRS759142 F

Figure 752: Functional module diagram

Level detector

This module compares the differential current I_A to the set

module is activated if the differential current exceeds the value set in the

The time characteristic is according to DT. When the alarm timer reaches the value

the module generates an alarm signal, the reset timer is activated. If the reset timer

reaches the value set by

the BLOCK signal resets the Timer and deactivates the ALARM output.

Lockout logic

HZCCxSPVC is provided with the possibility to activate a lockout for the ALARM

output depending on the

ALARM must be reset manually from the LHMI Clear menu after checking the CT

secondary circuit. In the "Non-latched" mode, the ALARM output functions normally,

that is, it resets as soon as the fault is cleared.

Measuring modes

The function operates on two alternative measurement modes, DFT and Peak-to-

Peak. The measurement mode is selected using the

Technical Manual

Alarm delay time , the ALARM output is activated. If the fault disappears before

Reset delay time , the alarm timer resets. The activation of

Alarm output mode setting. In the "Lockout" mode, the

Supervision functions

Start value . The timer

Measurement mode setting.