Limiting Functions - Allen-Bradley 1407-CGCM-DLR User Manual

Chapter 3 CGCM-DLR Unit Operation
54

Limiting Functions

This section discusses the different types of limiting functions the CGCM-DLR
unit provides.
• Volts/Hertz Limit
• Over-excitation Limit
• Under-excitation Limit
Generator Capability Curve
The generator capability curve graphically depicts the combinations of real and
reactive power a generator is able to produce (or absorb, in the case of reactive
power) without damage that is caused by overheating. The CGCM-DLR unit
provides a number of limiting functions that are designed to maintain operation
within safe areas of the generator capability curve.
A typical generator capability curve is shown in the following illustration.
Figure 30 - Typical Generator Capability Curve
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
-1.0
0.0 0.2
Rockwell Automation Publication 1407-UM002B-EN-P - February 2019
Field Winding
Heating Limitation
Rating PF
Lagging
Armature Winding
Heating Limitation
Prime Mover
Power Limitation
95% PF
Leading
Armature Core
End Iron Heating
Limitation
0.4 0.6 0.8 1.0 1.2
Real Power, per Unit
1.4