I.L. 40-201.9
Power Automation and Protection Division
5-2
REL 352 Version 1.00
For Example:
Set CTR = 240 if 1200/5 line ct’s are being used.
2.6
Voltage Transformer Ratio (VTR)
This setting is used for the system voltage monitoring, if it is selected to be displayed in primary
kVolts. It has no effect on the protective relaying system.
For Example:
Set VTR = 575 if 69000 V to 120 V vt’s are being used.
3.
OSCILLOGRAPHIC INFORMATION
3.1
Trigger for Storing Oscillographic Data (OSC)
Indicates trigger for oscillographic data gathering. The user can select the trigger of oscillo-
graphic data when:
• TRIP
— The REL 352 system tripped
• ITRG
— The REL 352 system detected the operation of either the TRGP or
TRGG, phase or ground current trigger respectively (see below).
•
∆
V,
∆
I — The REL 352 system has detected a fault in the system that may not
even be within the protective zone of the relay
The change detector occurs when current or voltage change between the corresponding data
samples, spaced one power line cycle apart, exceeds 12.5%.
Using of CD as a trigger of oscillographic data is of little practical value when a relay is connect-
ed to a “live” power system.
Numerous changes due to sudden load changes, remote switching, distant faults, etc., make
the resulting oscillographic records difficult to relate to events of importance.
3.2
Ground Trigger Pick UP Level (TRGG)
This setting controls the tolerance in the change of current magnitude,
∆
I, on the ground cur-
rent, to start oscillographic data gathering.
3.3
Phase Trigger Pick Up Level (TRGP)
This setting controls the tolerance in the change of current magnitude,
∆
I, on the phase currents
to start oscillographic data gathering.
4.
PHASE COMPARISON - LOGIC SETTINGS
4.1
Change detector option (CD)
The Change Detector (CD) is used for the following:
• Supervision of Trip Function (see figure 3-7).
