Single-Pole Tripping; Overview - GE D60 Instruction Manual

CHAPTER 9: THEORY OF OPERATION

SINGLE-POLE TRIPPING

9.5 Single-pole tripping

9.5.1 Overview

9.5.1.1 Introduction
Single pole operations make use of many features of the relay. At minimum, the trip output, recloser, breaker control, open
pole detector, and phase selector must be fully programmed and in service; and either protection elements or digital
inputs representing fault detection must be available for successful operation. When single pole trip-and-reclose is
required overall control within the relay is performed by the trip output element. This element includes interfaces with
pilot-aided schemes, the line pickup, breaker control, and breaker failure elements.
Single pole operations are based on use of the phase selector to identify the type of the fault, to eliminate incorrect fault
identification that can be made by distance elements in some circumstances and to provide trip initiation from elements
that are not capable of any fault type identification, such as high-set negative-sequence directional overcurrent element.
The scheme is also designed to make use of the advantages provided by communications channels with multiple-bit
capacities for fault identification.
Figure 9-9: Single-pole operation
9
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
D60 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL 9-23