GE 845 - System

4–70 845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
SYSTEM CHAPTER 4: SETPOINTS
System
Figure 4-18: System Display Hierarchy
To measure and function properly, the following information must be entered on the
845
relay:
• Current Sensing: information related to phase and ground CT primary ratings
• Voltage Sensing: information related to Phase and Aux. VT connections, secondary
voltage, and VT ratios
• Power Sensing: information related to voltage and current banks polarity residing on
the same card
• Power System: information related to system frequency, tracking frequency, phase
rotation Transformer: information related to transformer losses, temperature rise over
ambient, winding resistance, type of transformer, capacity, winding voltage, phase
shifting, grounding, etc.
• Breakers: information related to detecting the status of breakers by assigning contact
inputs
• FlexCurves: information related to inverse time curves with user-programmable points