Electra

ELECTRA is the bilingual journal of the Association. 
It is issued every two months and gives information on the work performed by the Study Committees and on the life of the Association. It is circulated free of charge to Members, as an inherent asset of membership. 

Members may download free of charge all publications including most recent ones. Non Members may download free of charge publications over three years old and purchase all publications.

A List of papers published by SC 14, former Committee on HVDC and Power Electronics, or by SC B4, the present one is presented underneath. 

ELECTRA PUBLICATIONS for all Study Committees 

ELECTRA

SCB4 & SC14 ELECTRA PUBLICATIONS (1967-2017) -Nov (pdf, 273kB)

e-cigre

Rules for Publications ELECTRA (pdf, 129kB)

 List of Electra publications:

ELT_294_3 2017 WG B4.63 Testing and commissioning of VSC HVDC systems

The Technical Brochure provides a practical guideline for the testing and commissioning of VSC HVDC schemes including a complete description of each of the three stages of commissioning (factory tests, subsystems tests and system tests). This technical brochure provides a summary of typical tests that make up each stage of testing and commissioning and for the system testing elements, provides a guide on the purpose, preconditions, procedure and acceptance criteria applicable to each test. The technical brochure also deals with other key aspects of the testing and commissioning of VSC systems, including the management of the commissioning process, training opportunities, documentation and approaches to deal with practical limitations to on site testing.

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ELT_292_2 2017 JWG B4/C1.65 Recommended voltages for HVDC grids

This technical brochure provides guidance for system planners and designers to choose the optimal DC voltage for High Voltage Direct Current (HVDC) grids. This includes a clear technical definition for the "DC voltage" in line with current practices and standards, a list of recommended values based on technical considerations and drivers from system planning, and a flowchart to guide the selection of the optimal voltage for individual projects.

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ELT_292_1 2017 JWG A3/B4.34 Technical requirements and specifications of state-of-the-art HVDC switching equipment

The new applications projected for future DC grids and multi-terminal DC systems at different voltages suggest that various DC equipment may be required; in particular all sorts of switching devices. However, the requirements for DC switching capabilities are different from those for AC equipment. In the brochure, a review of the technical requirements of HVDC switching equipment and an overview on the technical capabilities and limitations of existing switching equipment is given. Included are all sorts of switchgear such as disconnecting switches, earthing switches, transfer switches, and especially circuit breakers.

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ELT_290_3 2017 WG B4.62 Connection of wind farms to weak AC networks

Issues with connection of wind power plants (WPP) to weak AC systems and how to improve the performance of these systems have been addressed. The Working Group has also investigated the interactions between wind generator converter systems, power system, and other power electronic in the vicinity. Guidelines for screening of potential connection points, selection of WPP models, and possible avenues for mitigating the issues are provided.

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ELT_288_3 2016 WG B4.53 Guidelines for the procurement and testing of STATCOMS

This document is expected to be used by System Planners, System Operators, System Users, Investors and all other stakeholders that will be involved in the various stages of a STATCOM project, from the project inception to the final date when placed in service. As the technology used in STATCOM's advance, this brochure attempts to give high level guidance to how to properly procure and test a STATCOM installation without defining how one should explicitly specify the equipment required. In saying this, a great deal of the content of this brochure is based upon the contributing member's experience in either integrating a STATCOM into their grid or supplying one. The technology associated with STATCOMs is developing very quickly, with many vendors able to supply quality equipment. In order not to interfere with what vendors may be able to supply and developing test standards produced by CIGRE and other international organizations (IEC, IEEE), reference are made to existing standards where applicable.

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ELT_286_6 2016 WG B4.56 Guidelines for the preparation of “connection agreements” or “Grid Codes” for multi-terminal DC schemes and DC Grids

In the light of recent advancement of HVDC technology and the prospect of DC grid projects a need to address the required guide lines to develop the DC grid codes has arisen. Grid Codes or network codes are a set of rules and guidelines that govern a power system environment with multiple stakeholders, which describe e.g. the technical requirements that the equipment must fulfil in order to be integrated in the system and the rules and guidelines for interactions between the systems and stakeholders under steady state or abnormal operation conditions. This brochure provides recommendations on the models of interactions between the stakeholders and activities from planning to operation including technical aspects of planning, building and operation of a DC grid. Based on these recommendations a specific (set of) grid code(s) can be developed for the DC grid. The focus of this document is on the MTDC grids, and not on the HVAC networks which are connected to these DC grids. The objective of this brochure is to support the concerned stakeholders i.e. system planners, system operators (SO) and system users, to develop their own particular DC grid code.

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ELT_285_6 2016 WG B4.54 Guidelines for life extension of existing HVDC systems

HVDC systems have been in commercial use since 1954, and most of them are still in operation. Renovation, modernization and life extension of HVDC stations have to be considered by utilities and grid operators, as they are usually the most cost effective options for maintaining continuity and reliability of the power supply to the consumers. This BT provides guidelines for making the technical and economic decision on life extension of existing HVDC stations against replacement.

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ELT_281_3 2015 WG B4.55 HVDC Connection of Offshore WindPower Plants

The first wave of HVDC connected offshore wind power plants (WPPs) has been commissioned and many more are planned in the North Sea, along with other sites around the world. VSC-based HVDC has become the preferred solution for large offshore WPPs, with cable distances typically above 100 km (including both offshore cable and on shore cable to the converter terminal) to the AC grid connection point. This is largely due to several technology advantages offered by VSCs, when compared to other HVAC or HVDC options, resulting in a more economically attractive transmission solution. Guidelines and recommendation for point to point and multi terminal HVDC connection of offshore WPPs are therefore highly needed and of mutual interest for the HVDC and WTG industries in order to be able to provide the best possible solutions for all stakeholders.

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ELT_280_8 2015 WG B4.04 Converter Transformer Failure Survey Results From 2003 to 2012

Every year, the Advisory Group AG B4.04collects information on the performance of HVDC systems around the world. Over the last 20 years this data has shown that converter transformers in Line Commutated Converter systems are the single largest contributors to the forced energy unavailability. In order to provide more detailed information on the transformer failures, AG B4.04also conducts survey on transformer failures every two years. The results of the surveys conducted on failures from 2003 to 2012 are described in this brochure.

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ELT_279_7 2015 WG B4.51 Study of Converter Transients

Imposed on the HVDC Converter TransformersThe LCC HVDC converter transformers are connected between the AC system and the HVDC converter. A converter transformer is subjected to voltage and current transients as a result of normal converter operation and the faults on the converter side. This document identifies the voltage and current transients imposed by the converter that must be taken into account by the transformer designer.

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ELT_279_2 2015 WG B4.37 Guide for the Development of Models for HVDC Converters in a HVDC Grid

The TB documents the requirements of simulation models for modular multi-level voltage-sourced converters (MMC-VSC) that would form the basis of a DC Grid and provides a framework for model development that is consistent with known MMC-VSC technologies presently used. This framework can be adapted to changing power electronic topologies and control algorithms. In addition, a 9 bus DC Grid test system was developed and documented. Two and four bus test systems that are subsets of the 9 bus system are also presented.

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ELT_276_6 2014 WG B4.04 Protocol for Reporting Operational Performance of HVDC Systems

Advisory Group AG B4.04 of CIGRE committee B4 collects data annually on the operational performance of HVDC systems. The data is summarized and presented as a paper bi-annually at the Paris session. The protocol provides a standard format for reporting operational performance. The new protocol has been revised to include both LCC and VSC converter systems.

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ELT_271_8 2013 WG B4.38 Modelling and Simulation Studies to be performed during the lifecycle of HVDCSystems

The TB provides an overview of the simulation tools, models and study procedures used throughout the lifecycle of an HVDC project. It outlines the essential capabilities of the applicable simulation tools and identifies the process or sequences of conducting simulation studies throughout the lifetime of the project. It primarily focuses on the technical aspects of simulation, modelling and studies that may be required for the integration of HVDC systems in AC systems.

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ELT_270_4 2013 WG B4.47 Special Aspects of AC Filter Design for HVDC Systems

This new TB is intended as an Addendum to the 1999 TB 139 'Guide to the Specification and Design Evaluation of AC Filters for HVDC Projects', which was subsequently converted into IEC/TR 62001. It addresses four areas which continue to be problematic and controversial: a.c. network harmonic impedance, pre-existing harmonics, a.c.-d.c. harmonic interaction, and current-based interference criteria. As well as making recommendations, it attempts to inform and explain, so that project-specific decisions can be made with full knowledge of the technical background while balancing the risks and benefits appropriately.

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ELT_267_8 2013 JWG C4/B4/C1.604 Influence of Embedded HVDC Transmission on System Security and AC Network Performance

This brochure highlights the gain in flexibility provided by an embedded HVDC link (defined as a DC link with at least two ends connected to a single synchronous AC network) for an existing HVAC grid. It also points out the possible technical issues that may arise, along with the different capabilities and performances depending on the underlying DC technology. Illustrations through existing or planned projects are proposed, in addition to open models for a benchmark network and VSC converters.

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ELT_267_5 2013 WG B4.52 HVDC Grid Feasibility Study

Until now most HVDC schemes have been point to point connections. A few multi-terminal schemes have been built with one extra terminal. But there have been many discussions of using HVDC for more advanced grids. The TB investigates the technical and economic feasibility to build such HVDC grids. The first question to answer is if HVDC grids offer any advantage over many point to point HVDC connections inside an AC grid. Another important question is if it will be possible to build HVDC breakers that are necessary to make the grid reliable. One more question is if one can make protections and control to the grid. These and many other challenging questions are studied in the Brochure.

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ELT_264_2 2012 WG B4.44 HVDC Environmental Planning Guidelines

The guideline provides an overview of the environmental issues to be considered in the technical design and environmental approval processes associated with an HVDC system. It provides an overview of the different HVDC systems and their components, with a focus on possible environmental issues. The environmental impacts and possible mitigation measures of the components and sub-components of HVDC schemes are described.

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ELT_259_8 2011 WG B5/B4.25 Impact of HVDC Stations on Protection of AC Systems

Operating experience has shown that in most cases the impacts of the HVDC system on the protection of adjacent HVAC systems are negligible, while in some special cases the HVDC system may bring about different fault characteristics to the adjacent HVAC system and influence the operation of the HVAC protection. The TB analyses the phenomenon in HVAC systems brought about by HVDC transmission systems and the resulting impacts on the operation of HVAC protection, and provides guidance on designing a proper HVAC protection system in the presence of adjacent HVDC systems.

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ELT_257_7 2011 WG B4/C3/B2.50 Electric Field and Ion Current Environment of HVDC Overhead Transmission Lines

This TB presents a report on the Electric Field and Ion Current Environment of HVDC Overhead transmission Lines. It provides information on the electric fields and ion currents produced by DC overhead transmission ines, the methods for calculating these parameters, field data measured under some operating lines and test lines, an evaluation of current scientific research on potential health and environmental implications of xposures to DC electric fields and ions, and a discussion of the role that sensory perception of field and ions may have in the design of DC lines. Examples of how design parameters that affect the levels of DC electric fields and ion current densities under DC lines are included.

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ELT_254_4 2011 WG B4.48 Components Testing of VSC System for HVDC Applications

The increasing application of VSC technology in HVDC transmission demands in-depth research on the tests of related components and subsystems in VSC system. So WG B4.48 was organized to carry out such research and prepare the TB. The brochure gives detailed description of component stresses under steady-state condition and fault condition respectively, followed by the test philosophies. The useful test procedures are also presented.

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ELT_250_4 2010 WG B4.45 Technological Assessment of 800kV HVDC Applications

Studies carried out by the WG and work being carried out by manufacturers show that no major problem is anticipated with the implementation of 800kVdc HVDC technology,considered techno-economical where large amounts ofpower is to be transmitted over long distances. The test levels specified in this TB should be beneficial to utilities and manufacturers and should streamline the requirements of testing and test values.

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ELT_250_3 2010 WG B4.45 Innovative Solutions for Overhead Line Supports

Years ago, aesthetics was not taken into account in the design of OHL supports. Towers were not judged as 'pretty' or 'ugly'; they were just considered essential for transmission of electricity. Nowadays, overhead line projects have tostart with an environmental impact assessment aiming toreduce their impact on the landscape. This brochure produced by WG B2.08 has the purpose of reporting how aesthetic towers have been used as a solution to mitigate these impacts.

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ELT_248_6 2010 JWG A2/B4.28 406 HVDC Converter Transformers - Design review, test procedures, ageing evaluation and reliability in service. 407 HVDC Converter Transformers - Guidelines for conducting design reviews for HVDC converter transformers

406 - JWG A2/B4.28 monitored the reliability in service of HVDC Converter Transformers and the TB reports, over a period 1971-2009, an encouraging decrease in the failure rate. It also reviewed existing standard test specifications, with a view of representing the real service conditions. The importance of the Polarity Reversal (PR) test and the effect of the oil conductivity and the polarization time are stressed. The conclusion is that at this stage the existing test should not be modified. 407 - A design review provides a common customer-manufacturer understanding of the applicable standards and specification requirements. It is an opportunity to scrutinize the design to ensure the requirements will be met, using the manufacturer's proven materials and methodology. This document prepared by A2/B4.28, is based on the existing guide (TB 204) while expanding to address specific aspects associated with the HVDC Converter Transformer, such as higher harmonic or transient waveforms.

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ELT_245_4 2009 JWG B2/B4/C1.17 Impacts of HVDC lines on the economics of HVDC project

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ELT_242_7 2009 WG B4.40 Static Synchronous Series Compensator (SSSC)

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ELT_241_6 2008 WG B4.41 Systems with multiple DC Infeed

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ELT_238_6 2008 WG B4.34 Capacitor Commutated Converted (CCC) HVDC Interconnections: Digital modeling and Benchmark Circuit

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ELT_235_4 2007 JWG B4/A3/B3.43 Increased System Efficiency by Use of New Generations of Power Semiconductors

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ELT_233_2 2007 WG B4.41 Systems with multiple DC infeed

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ELT_222_5 2005 WG B4.33 HVDC and FACTS for distribution systems

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ELT_219_4 2005 WG B4.37 VSC Transmission

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ELT_213_5 2004 WG B4.35 Thyristor controlled voltage regulators- Part 2: Static on-load transformer tap changers

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ELT_212_7 2004 WG B4.35 Thyristor controlled voltage regulators- Part 1 : Non-conventional static reactive power regulation

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ELT_212_6 2004 JWG B4.O4/A2.1 Analysis of HVDC thyristor converter transformer performance

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ELT_211_4 2003 WG B4.19 Static synchronous compensator (STATCOM) for arc furnace and flicker compensation

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ELT_207_5 2003 WG 14.28 Active filters in HVDC applications

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ELT_207_4 2003 WG 14.05 On voltage and power stability in AC/DC systems

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ELT_205_5 2002 WG 14.32 HVDC converter stations for DC voltages above +/- 600 kV

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ELT_203_5 2002 WG 14.31 Custom power - State-of-the-art

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ELT_196_4 2001 WG 14.20 Economic assessment of HVDC links

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ELT_195_4 2001 FACTS technology for open access

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ELT_193_1 2000 SC 12/13/14/15/21/23/37 High temperature superconductor applications in electrical power systems.

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ELT_187_1 1999 Active DC filters in HVDC applications.

ELT_174_1 1997 JWG 12/14.10 Load losses in HVDC converter transformers

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ELT_171_1 1997 WG 14.02 On the control of a multiterminal HVDC system having also weak inverter stations.

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ELT_169_4 1996 WG 14.02 Commutation Failures in HVDC Transmission Systems due to AC System Faults

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ELT_167_3 1996 JWG 12/14.10 Consideration of impedance and tolerances for HVDC converter transformer.

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ELT_167_1 1996 JWG 11/14.09 Adjustable Speed Operation of Hydraulic Turbine Generators

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ELT_164_2 1996 JWG 13/14.08 Circuit-breakers for meshed multi-terminal HVDC systems. Part II : Switching of transmission lines in meshed MTDC systems.

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ELT_163_4 1995 JWG 13/14.08 Circuit-breakers for meshed multiterminal HVDC systems. Part 1 : Introduction - DC side substation switching under normal and fault conditions.

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ELT_159_2 1995 WG 14.03 Connection of harmonic producing installations in AC high voltage networks with particular reference to HVDC.

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ELT_157_2 1994 WG 14.02 The CIGRE HVDC Benchmark Model: A new Proposal with Revised Parameters.

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ELT_157_1 1994 JWG 12/14.10 The relationship between test and service stresses as a function of resistivity ratio for HVDC converter transformer and smoothing reactors.

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ELT_155_1 1994 JWG 12/14.10.01 In-service performance of HVDC converter transformers and oil-cooled smoothing reactors.

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ELT_149_4 1993 JWG 14.03/36.05 Connection of harmonics producing installations in AC high voltage networks with particular reference to HVDC. Guide for limiting harmonic voltage effects.

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ELT_149_2 1993 JWG 11/14.09 Direct Connection of Generators to HVDC Converters: Main Characteristics and Comparative Advantages

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ELT_135_4 1991 WG 14.02 First Benchmark Model for HVDC Control Studies

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ELT_135_3 1991 JWG 13/14.08 Switching devices other than circuit-breakers for HVDC systems. Part 2 : Disconnectors and earthing switches.

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ELT_125_2 1989 TF 14.01.01 Voltage and Current Stresses on HVDC Valves

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ELT_125_1 1989 JWG 13/14.08 Switching devices other than circuit-breakers for HVDC systems. Part I : Current commutation switches.

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ELT_124_2 1989 JWG 13/14.08 The current commutation function of HVDC switching devices.

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ELT_091_2 1983 Use of static or synchronous compensators in HVDC systems

ELT_064_2 1979 Design and test methods for combined spark gaps of DC arresters

ELT_063_2 1979 WG 14.03 A general survey of AC harmonic filters and reactive compensation for HVDC

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ELT_057_1 1978 A ten year review of HVDC transmission systems 1967-1976

ELT_038_2 1975 Observation of overvoltages under normal commercial operation at the AC/DC converter station Lydd.

ELT_034_1 1974 SC 14/33 Insulation Levels for HVDC Terminals

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