GE B90 Instruction Manual page 370

GROUPED ELEMENTS CHAPTER 5: SETTINGS
— This setting allows extra security when tripping the bus from the EFP element. This timer shall be set
EFP1 PICKUP DELAY
longer than the maximum delay between the breaker closing and picking up some current and the
EFP MANUAL CLOSE
signal. If the manual close signal, , arrives before the timer expires, the element resets and misoperation
EFP MANUAL CLOSE
due to signal transit times is avoided.
— This setting dynamically block/unblocks the element. A typical application is a by-pass isolator as shown
EFP1 BLOCK
below. When the isolator is closed, the current does not necessarily indicate on a fault between the CB and CT and the
element shall be blocked. Therefore, the close status of the isolator shall be used as the block setting.
Figure 5-94: End fault protection and bypass isolators
5
Figure 5-95: End fault protection logic
5-178 B90 LOW IMPEDANCE BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL