CHAPTER 5: SETTINGS
and the magnitude of the neutral and zero-sequence voltages |V
Therefore, for faults at a fraction k = 0.15 from the neutral grounding point, we set the operating quantities as follows:
The 100% stator ground settings are described as follows.
100% STATOR GND STG1 PICKUP
measure the operating quantity under various load conditions for a particular machine in order to optimize this setting.
This can be achieved using the actual values menu of the G60.
100% STATOR GND STG1 DELAY
established.
— This setting specifies a signal level supervision for the vectorial sum of the third harmonic at
100% STATOR GND STG1 SUPV
the machine neutral and in the zero-sequence terminal voltage. The setting is entered as a per-unit value of the terminal
voltages. Different settings can be considered for stages 1 and 2 as one of them can be used for alarm and the other for
trip. The safe value of this setting can be established after putting a given machine into service and reading the quantity
from the relay under the
ACTUAL VALUES
5.7.17.3 Third harmonic neutral undervoltage (ANSI 27TN)
SETTINGS GROUPED ELEMENTS SETTING GROUP 1(6) STATOR GROUND 3RD HARM NTRL
UNDERVOLTAGE
3RD HARM NTRL
UNDERVOLTAGE
G60 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
— This setting specifies a pickup level for the operating quantity. It can be beneficial to
— This setting specifies a time delay required to operate after the pickup condition is
menu.
Figure 5-176: Stator ground logic
3RD HARM NTRL UV
FUNCTION: Disabled
3RD HARM NTRL UV
PICKUP: 0.3000 pu
+ V
| as:
N
0
Range: Disabled, Enabled
Range: 0.0010 to 3.0000 pu in steps of 0.0001
GROUPED ELEMENTS
Eq. 5-43
Eq. 5-44
5
5-305