13.8-kV Selective High-Resistance Grounding System for a Geothermal Generating Plant—A Case Study

Author

Das, J.C. ; Perich, E.

Author_Institution

AMEC E&C Services Inc., Tucker, GA, USA

Volume

49

Issue

3

fYear

2013

fDate

May-June 2013

Firstpage

1234

Lastpage

1243

Abstract

The 13.8-kV selective high-resistance grounding (HRG) systems for bus-connected generators are nonexistent due to two reasons: One is that the stray capacitance current of the system can be high (> 10-12 A), and the other is that the sensitivity and selectivity of the ground-fault devices to detect low levels of ground-fault currents are required. This paper describes the relay types, sensors, settings on protective relays, and flow of currents for various fault locations in a 13.8-kV system and demonstrates how a selective HRG has been implemented. To the authors´ knowledge, there is no HRG selective system at 13.8 kV.

Keywords

fault location; geothermal power stations; bus-connected generators; fault locations; geothermal generating plant; ground-fault devices; high-resistance grounding system; relay types; stray capacitance current; voltage 13.8 kV; Capacitance; Circuit faults; Fault currents; Generators; Grounding; Relays; Windings; Neutral displacement relays; selective high-resistance grounding (HRG) system; sensitive ground-fault settings and coordination; zigzag grounding transformer;

fLanguage

English

Journal_Title

Industry Applications, IEEE Transactions on

Publisher

ieee

ISSN

0093-9994

Type

jour

DOI

10.1109/TIA.2013.2252134

Filename

6478869