ERL L-PRO 4000, User Manual

Page: 84 / 406

4 Protection Functions and Specifications
4-34 L-PRO 4000 User Manual D02706R02.30
Figure 4.18: 60 CT Supervision
81 Frequency
The relay has 4 frequency devices available. Each frequency element can be
set to operate either at a fixed level of under-frequency, a fixed level of over-
frequency, or at a rate of change level (df/dt). The df/dt function can be set to
operate for a positive rate of change or a negative rate of change. Each frequen-
cy element has a definite time delay setting to create a time delayed output. A
fixed level of positive sequence voltage of 0.25 pu provides an undervoltage
inhibit on each element
Figure 4.19: Frequency Fixed Level
Figure 4.20: Frequency Rate of Change
Table 4.17: 60 CT Supervision Settings
Main Enable/Disable
Inps Pickup 0.25 to 5.00 A secondary (5A)
0.05 to 1.00 A secondary (1A)
Vnps Pickup 7.00 to 110.00 V secondary
Pickup Delay 0.03 to 99.99 seconds
Auxiliary Enable/Disable
Inps Pickup 0.25 to 5.00 A secondary (5A)
0.05 to 1.00 A secondary (1A)
Vnps Pickup 7.00 to 110.00 V secondary
Pickup Delay 0.03 to 99.99 seconds
Table 4.18: 81 Over/Under Frequency Settings
Disabled/Fixed Level/Rate of Change
T
O
Frequency (Hz)
T
O
df/dt (Hz/s)