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 START output. Another
consequence is that if only one or two phases are monitored, it is sufficient that
these monitored phases activate the START output.
10.3.4.2 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 start signals when Phase mode
is "Single Phase", are as shown in the example for the detection of a
three-phase interruption.
Section 10 1YHT530004D05 D
Power quality measurement functions
774 615 series
Technical Manual
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