ABB RELION 620 Series Technical Manual page 684

Section 8
Power quality measurement functions
8.3.4.2
678
However, when Phase mode is "Three Phase", all the monitored phase signal magnitudes,
defined with Phase supervision, have to fall below or rise above the limit setting to
activate the PICKUP output and the corresponding phase output, that is, all the monitored
phases have to be activated. Accordingly, the deactivation occurs when the activation
requirement is not fulfilled, that is, one or more monitored phase signal magnitudes return
beyond their limits. Phases do not need to be activated by the same variation type to
activate the PICKUP output. Another consequence is that if only one or two phases are
monitored, it is sufficient that these monitored phases activate the PICKUP output.
Variation detection
The module compares the measured voltage against the limit settings. If there is a
permanent undervoltage or overvoltage, the Reference voltage setting can be set to this
voltage level to avoid the undesired voltage dip or swell indications. This is accomplished
by converting the variation limits with the Reference voltage setting in the variation
detection module, that is, when there is a voltage different from the nominal voltage, the
Reference voltage setting is set to this voltage.
The Variation enable setting is used for enabling or disabling the variation types. By
default, the setting value is "Swell+dip+Int" and all the alternative variation types are
indicated. For example, for setting "Swell+dip", the interruption detection is not active
and only swell or dip events are indicated.
In a case where Phase mode is "Single Phase" and the dip functionality is available, the
output DIPST is activated when the measured TRMS value drops below the Voltage dip
set 3 setting in one phase and also remains above the Voltage Int set setting. If the voltage
drops below the Voltage Int set setting, the output INTST is activated. INTST is
deactivated when the voltage value rises above the setting Voltage Int set. When the same
measured TRMS magnitude rises above the setting Voltage swell set 3, the SWELLST
output is activated.
There are three setting value limits for dip (Voltage dip set 1..3) and swell activation
(Voltage swell set 1..3) and one setting value limit for interruption.
If Phase mode is "Three Phase", the DIPST and INTST outputs are
activated when the voltage levels of all monitored phases, defined with the
parameter Phase supervision, drop below the Voltage Int set setting value.
An example for the detection principle of voltage interruption for "Three
Phase" when Phase supervision is "Ph A + B + C", and also the
corresponding pickup signals when Phase mode is "Single Phase", are as
shown in the example for the detection of a three-phase interruption.
1MAC504801-IB E
620 series ANSI
Technical Manual