ABB RELION REX640 Technical Manual page 1120

Protection and control

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Table of Contents

Protection functions

exceeds the set limit. The operation time characteristics can be selected to be

either definite time (DT) or inverse definite minimum time (IDMT). The operation

under alarm stage is either based on the DT characteristics or the faulty element

counter of a capacitor bank.

CUBPTOC has a blocking functionality. It is possible to block the function outputs,

timers or the function itself.

Analog channel configuration

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

Table 1064: Analog inputs

There are a few special conditions which must be noted with the configuration.

Table 1065: Special conditions

IUNB measurement

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 current unbalance

protection for shunt capacitor banks operates on the DFT measurement mode.

The operation of CUBPTOC can be described by using a module diagram. All the

modules in the diagram are explained in the next sections.

Unbalance current (measured)

Three-phase currents

See the preprocessing function blocks in this document for the possible

signal sources.

The function requires that the unbalance current measure-

ment is connected via the RESTCTR function block.

1MRS759142 F

Operation setting. The

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