Reverse Power; System Backup Overcurrent - GE G30 Instruction Manual

SETTINGS

8.2.6 Reverse power

The reverse power element is set at ½ the rated motoring power. The pickup is calculated as follows:
For the example system:
To prevent maloperation for power swings the element is typically time delayed by 20 to 30 seconds. For sequential
tripping applications the time delay is to be 2 to 3 seconds. The element can be blocked when the generator is offline. The
line source is to be used for this application. Make the following changes in the EnerVista software or the front panel
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1  SENSITIVE DIRECTIONAL POWER  DIRECTIONAL POWER 1
Sequential tripping logic can be implemented in FlexLogic as follows.
8

8.2.7 System backup overcurrent

System backup protection is implemented using a phase time overcurrent element with voltage restraint enabled. The
NEUTRL source is to be chosen for this element. Set the pickup of this element at a safe margin above the maximum load
expected on the machine.
8-10
Figure 8-4: Sequential tripping FlexLogic
G30 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 8: APPLICATION OF SETTINGS
Eq. 8-15
Eq. 8-16
Eq. 8-17
menu.