GE C60 Instruction Manual page 525

CHAPTER 8: THEORY OF OPERATION
The trip output element receives requests for single and three-pole trips and three-pole reclose initiation, which it then
processes to generate outputs that are used to
• Determine whether a single or three-pole operation is to be performed
• Initiate tripping of breaker poles A, B, and C, either individually or as a group
• Initiate breaker failure protection for phases A, B, and C, either individually or as a group
• Notify the open pole detector when a single pole operation is imminent
• Initiate either single or three-pole reclosing
• Notify the phase selector when a trip operation is imminent
When notified that a single pole operation has been initiated, the open-pole detector
• Initiates blocking of protection elements that can potentially maloperate when a breaker pole is open
• Instructs the phase selector to de-assert all outputs, as an open pole invalidates calculations
It is assumed for this discussion that the relay features that are shown in the Single-Pole Operation figure have been
programmed for the application and are in service. The description begins with line breakers open at both the local and
remote ends, and the operation of the scheme is described in chronological order.
C60 BREAKER PROTECTION SYSTEM – INSTRUCTION MANUAL
Figure 8-3: Single-pole operation
SINGLE-POLE TRIPPING
8-5
8