ABB RELION REX640 Technical Manual page 407

Protection and control

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1MRS759142 F

Operation principle

The function can be enabled and disabled with the

corresponding parameter values are "On" and "Off".

The operation of PHPTUC can be described with a module diagram. All the modules

in the diagram are explained in the next sections.

Figure 236: Functional module diagram

Level detector 1

This module compares the phase currents (RMS value) to the

If in the "3-phase" mode all the phase current values are less than the value of the

Start value setting, the condition is detected and an enable signal is sent to the

timer. This signal is disabled after one or several phase currents have exceeded the

If in the "1-phase" mode any of the phase current values are less than the value of

timer. This signal is disabled after all the phase currents have exceeded the set

value value of the element.

Level detector 2

This is a low-current detection module that monitors the de-energized condition of

the protected object. The module compares the phase currents (RMS value) to the

Current block value setting. If all the phase current values are less than the Current

block value setting, a signal is sent to block the operation of the timer.

Once activated, the timer activates the START output and the phase-specific ST_X

output. The time characteristic is according to DT. When the operation timer has

reached the value set by

specific OPR_X output are activated. If the fault disappears before the module

Technical Manual

Operation mode setting can be used to select the "3-phase" or "1-phase" mode.

Start value value of the element.

Start value setting, the condition is detected and an enable signal is sent to the

The protection relay does not accept the

Current block value .

Operate delay time , the OPERATE output and the phase

Protection functions

Operation setting . The

Start value setting.

Start value to be smaller than