ABB RELION REX640 Technical Manual page 436

Protection and control

Hide thumbs Also See for RELION REX640:

Table of Contents

Protection functions

Figure 249: Functional module diagram

Harmonic selector

This module receives the shaft current measurement signal ISHAFT from the

measurement arrangement. The recommended measurement arrangements (axial

shaft CT with resistor or Rogowski coil with integrator) provide a voltage signal

which is amplified for the relay input. The voltage signal is converted to current

inside the function. Alternatively shaft current can be directly measured by relay

current input when CT is used alone.

The operating harmonic component is selected according to the

setting which is obtained from the commissioning test.

The selected harmonic component from the shaft current measurement is available

in monitored data under I_SHAFT. Additionally, each of the available harmonics are

available in monitored data under I_SHAFT_H1, I_SHAFT_H3 and I_SHAFT_H5.

Level detector 1

The module compares the measured shaft current to the setting

value , which is set in primary amps. If the level exceeds the set value, a enable signal

is sent to Timer 1 module.

Level detector 2

The module compares the measured shaft current to the setting

which is set in primary amps. If the level exceeds the set value, a enable signal is

sent to Timer 2 module.

Once activated, the Timer 1 activates the START output. The time characteristics

are according to DT. When the operate timer reaches the value set by

time , the OPERATE output is activated. If the fault disappears before the module

generates an OPERATE signal, the reset timer is activated. If the reset timer reaches

the value set by

The activation of the BLOCK signal resets the Timer 1 and deactivates the OPERATE

and START outputs.

Reset delay time , the operate timer resets.

1MRS759142 F

Select harmonic

Operate start

Alarm start value ,

Operate delay

Technical Manual