ABB RELION REX640, Technical Manual, Page: 852 / 1960

Condition Description
tages must be connected (third one will be
derived).
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.
4.5.1.5 Operation principle
The function can be enabled and disabled with the
Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of PHPTOV can be described using a module diagram. All the modules
in the diagram are explained in the next sections.
Figure 481: Functional module diagram
Level detector
The fundamental frequency component of the measured three-phase voltages are
compared phase-wise to the set value of the
Start value setting. If the measured
value is higher than the set value of the
Start value setting, the level detector
enables the phase selection logic module. The
Relative hysteresis setting can be
used for preventing unnecessary oscillations if the input signal slightly differs from
the
Start value setting. After leaving the hysteresis area, the start condition has to
be fulfilled again and it is not sufficient for the signal to only return to the hysteresis
area.
The
Voltage selection setting is used for selecting phase-to-earth or phase-to-
phase voltages for protection.
For the voltage IDMT operation mode, the used IDMT curve equations contain
discontinuity characteristics. The
Curve Sat Relative setting is used for preventing
undesired operation.
For a more detailed description of the IDMT curves and the use of the
Curve Sat Relative setting, see Chapter 11.3.1.3 IDMT curve saturation of
overvoltage protection
in this manual.
Phase selection logic
If the fault criteria are fulfilled in the level detector, the phase selection logic detects
the phase or phases in which the fault level is detected. If the number of faulty
Protection functions 1MRS759142 F
852 REX640
Technical Manual