ABB RELION REX640 Technical Manual page 789

Protection and control

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1MRS759142 F

Improper analog channel configuration causes a validation error if the analog

channels are not completely configured or they do not match with certain settings.

For troubleshooting, check the contents of this chapter and also the preprocessing

blocks in this document. The configuration can be written to the protection relay

once the mismatch is corrected.

Operation principle

The function can be enabled and disabled with the

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

The operation of MPDIF can be described using a module diagram. All the modules

in the diagram are explained in the next sections.

Figure 449: Functional module diagram

Differential and bias calculation

Differential calculation module calculates the differential current. The differential

current is the difference in current between the phase and neutral sides of the

The phase currents I

the phase and neutral sides of the current. The amplitude of the differential current I

is obtained using the equation (assuming that the positive direction of the current

is towards the machine):

Technical Manual

Differential

DC restraint

denote the fundamental frequency components on

Protection functions

Operation setting. The