ABB RELION REX640 Technical Manual page 1398

Protection and control

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Table of Contents

Condition monitoring functions

Cable fault detection RCFD (ANSI CFD)

Identification

Function description

Cable fault detection

Function block

Figure 793: Function block

Functionality

The self-clearing fault detection function (RCFD) calculates half cycle DFT of the

current signal for all the three phases and earth and uses it to detect a self-clearing

fault pronounced primarily in cable networks.

The function provides individual counter values for number of times a self-clearing

fault is observed in each phase and earth. The function determines the self-clearing

fault is detected in all three phases or earth.

Analog input configuration

RCFD has two analog group inputs which must be properly configured.

Table 1332: Analog inputs

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.

Three-phase currents.

Measured residual current

See the preprocessing function blocks in this document for the possible

signal sources.

identification

1MRS759142 F

ANSI/IEEE C37.2

device number

Technical Manual