IEEE Std 2771:2021 pdf free download – IEEE Guide for ParameterConfiguration of Arcing Hornsof DC Earth Electrode Lines
2. Normative references
The following referenced documents are indispensable for the application of this document(i.e., they mustbe understood and used, so each referenced document is cited in text and its relationship to this document isexplained).For dated references, only the edition cited applies. For undated references, the latest edition of thereferenced document (including any amendments or corrigenda) applies.
IEEE Std 1899TM-2017,IEEE Guide for Establishing Basic Requirements for High-Voltage Direct-CurrentTransmission Protection and Control Equipment.3.
IEC 60060-1:2010,High-Voltage Test Techniques—-Part 1:General Definitions and Test Requirements.*IEC 60071-2:2018,Insulation Co-ordination—Part 2:Application Guidelines.
IEC 60633:2019,Terminology for High-Voltage Direct Current (HVDC)Transmission.
IEC 61325:1995,Insulators for Overhead Lines with a Nominal Voltage above 1000 v—Ceramic or GlassInsulator Units for d.c.Systems—Definitions, Test methods and Acceptance Criteria.
3. Definitions, acronyms, and abbreviations
3.1 Definitions
For the purposes of this document, the following terms and definitions apply.TheIEEE Standards DictionaryOnline should be consulted for terms not defined in this clause.6
arcing horn: A lightning protection device connected in parallel with the insulators and generally composedof a high voltage side electrode, a grounding side electrode, and connection fittings. The gap distance of thearcing horn is less than the length of insulators, which can provide flashover path as well as transfer and guidethe arc.
earth electrode: Conducting elements placed in the earth or the sea, which provide a low resistance pathbetween a point in the dc circuit and the earth, and are capable of carrying continuous current for someextended period.(IEEE Std 1899TM-2017).7
earth return: Operation mode in which the return current path between neutrals of the HVDC substations isthrough the earth.(IEC 60633:2019)y.
electrode line: Insulated line between the HVDC substation dc neutral bus and the earth electrode.(IEEE Std 1899-2017).Syn: earth electrode line.
HVDC transmission system: An HVDC system that transfers energy between two or more geographiclocations.(IEEE Std 1899-2017).
pole (current) balancing:Control action to balance the currents in the two poles of a bipole system, in orderto limit the differential current that flows between the neutrals of the high-voltage direct-current system.(IEEE Std 1899-2017).
4.1 General
Voltage applied on arcing horns may be operating voltage, switching overvoltage, or lightning overvoltage.Voltage resulting in arcing horn breakdown is generally switching overvoltage and lightning overvoltage.Sustained dc arc current will occur on the arcing horn if the air gap of the arcing horn breaks down and theearth electrode line has large dc operating current. Sustained dc arc is difficult to extinguish naturally, whichmay cause the risk of insulator string falling apart, wire fracture, pole blocking, and other serious accidents.
4.2.1 Operating voltage
DC operating voltage results from dc operating current flowing through the earth electrode line.Earth electrodemay be individually configured for one HVDC substation, or shared across multiple HVDC substations, asshown in Figure 1. When the system operates in the balanced bipolar mode, the current on the earth electrodeline is very small. When the system operates in the monopolar earth return mode, all the operating currents willflow through the earth electrode line,resulting in the maximum operating voltage.