Woodward highprotec MRI4, User Manual

Page: 447 / 727

Protective Elements
Voltage Controlled Overcurrent Protection [51C]*
* =available only for devices that offer voltage measurement.
When a sort circuit is near the generator, the voltage might drop down. By means of Adaptive Parameters (Please
refer to chapter Parameter) the tripping times or tripping characteristics can be modified by the output signal of a
voltage element (depending on a threshold). The device might change a load curve to a fault curve (taking
influence on tripping time, trip curves and reset modes).
Please proceed as follows:
Read and understand the section „Adaptive Parameters“ within the chapter Parameter.
Do the device planning and set all required parameters for the Undervoltage element.
Do the device planning and set all required parameters for the Overcurrent element.
Set the Adaptive Parameters within the Overcurrent element in the relevant parameter sets (e.g. Curve
multiplier, curve type...).
Assign the Undervoltage alarm (pickup) within the Global Parameters as an activation signal for the
corresponding
Adaptive Parameter set of the overcurrent element that should be modified.
Check the functionality by a commissioning test.
447 MRI4 DOK-HB-MRI4-2E