A fresh look at limits to the sensitivity of line protection

Author

Schweitzer, Edmund O., III ; Fischer, Normann ; Kasztenny, Bogdan

fYear

2011

fDate

11-14 April 2011

Firstpage

44

Lastpage

55

Abstract

This paper considers the sensitivity of essential line protection elements: ground distance and ground directional overcurrent elements applied as time-coordinated functions or in pilot-assisted protection schemes and line current differential schemes. Factors discussed include fault resistance, line unbalance and charging currents, impact of in-line reactors, system short-circuit capacity, load encroachment and swings, sequential tripping and weak feed terminals, steady-state and transient errors of instrument transformers, impact of current transformers (CTs) in dual-breaker line terminals, and single-pole-open conditions. Protection element design improvements and application principles enhancing sensitivity are included.

Keywords

current transformers; earthing; instrument transformers; overcurrent protection; power transmission lines; power transmission protection; CT; charging current; current transformer; dual-breaker line terminal; fault resistance; ground directional overcurrent element; ground distance overcurrent element; in-line reactor impact; instrument transformer; line current differential scheme; line protection sensitivity; line unbalance; load encroachment; pilot-assisted protection scheme; protection element design improvement; sequential tripping; short-circuit capacity system; single-pole-open condition; steady-state error; time-coordinated function; transient error; weak feed terminal; Circuit faults; Current measurement; Grounding; Impedance; Instrument transformers; Security; Sensitivity;

fLanguage

English

Publisher

ieee

Conference_Titel

Protective Relay Engineers, 2011 64th Annual Conference for

Conference_Location

College Station, TX

Print_ISBN

978-1-4577-0494-9

Type

conf

DOI

10.1109/CPRE.2011.6035604

Filename

6035604