1 Design, Control and Application of Modular Multilevel Converters for HVDC Transmission Systems by Kamran Sharifabadi, Lennart Harnefors, Hans-Peter Nee, Staffan Norrga, Remus Teodorescu ISBN-10: 1118851560 Copyright Wiley 2016 Chapter 8 MMC-HVDC Standards and Commissioning Procedures
Outline (1) Introduction 8.2 CIGRE and IEC Activities for the Standardization of MMC-HVDC Technology 8.2.1 Hierarchy of Available and Applicable Codes, Standards and Best Practice Recommendations for MMC-HVDC Projects 8.3 MMC-HVDC Commissioning and Factory and Site Acceptance Tests 8.3.1 Pre-Commissioning 8.3.2 Offsite Commissioning Tests or Factory Acceptance Tests 8.3.3 Onsite Testing and Site Acceptance Tests 8.3.4 Onsite Energizing Tests 8.4 Summary 2
Introduction Most of the modular multilevel converter high-voltage direct current (MMC- HVDC) projects are planned and developed as point-to-point transmission scheme projects, where the HVDC equipment are designed, manufactured, and installed by the same HVDC original equipment manufacturer (OEM). The HVDC project customers define the functional requirements, including the grid-code requirements that must be fulfilled by the procured equipment. During the bidding process, the HVDC OEM normally will document the compliance of the tendered HVDC scheme with the customer requirements through adequate system studies and simulations. This chapter provides an overview of standards applicable to HVDC equipment developed by professional associations in the field of MMC- HVDC technology. In addition, best practice recommendations for factory and site acceptance tests are presented. 3
CIGRE and IEC Activities for the Standardization of MMC-HVDC Technology Worldwide, various professional associations have taken initiatives to facilitate and develop the necessary recommendations and standards. Professional associations such as IEC, CIGRE, CENELEC, and IEEE are promoting and facilitating activities toward the standardization of MMC-HVDC technology worldwide. CIGRE, the Council on Large Electric Systems, was founded in 1921 and is an international non-profit association for promoting collaboration with experts from around the world by sharing knowledge and joining forces to improve the electric power systems of today and tomorrow. CIGRE Study Committee B4 (SC B4) addresses all aspects of power electronics, HVDC, and FACTS. 4
Hierarchy of Available and Applicable Standards for MMC-HVDC Projects IEC 60044-1 Instrument Transformers: Part 1: Current Transformers IEC 60071 Insulation Coordination IEC 60076 Power Transformers IEC 60099-4 Gapless Metal Oxide Surge Arresters for AC Systems IEC 60099-5 Surge Arresters: Selection and Application Recommendations IEC 60137 Insulated Bushings for AC Voltages above 1000 V IEC 62501 Voltage Sourced Converter (VSC) Valves for High Voltage Direct Current (HVDC) Power Transmission, Electrical Testing IEC 60146 Semiconductor Converters: General Requirements and Line Commutated Converters IEC 60076-6 Reactors IEC 60358 Coupling Capacitors and Capacitor Dividers IEC 60633 Terminology for HVDC Transmission IEC 60694 Common Specifications for High-Voltage Switchgear and Controlgear Standards IEC 61071-1 Power Electronic Capacitors: General IEC 61803 Determination of Power Losses in HVDC Converter Stations IEC 61954 Power Electronics for Electrical Transmission and Distribution Systems: Testing of Thyristors Valves for SVCs IEC 60815 Guide for Selection of Insulators in respect of Polluted Conditions IEC 60273 Characteristics of Indoor and Outdoor Post Insulators for Systems with Nominal Voltages greater than 1000 V IEC 60282-2 High-Voltage Fuses IEC 60439 Low-Voltage Switchgear and Controlgear Assemblies IEC 60715 Dimensions of Low-Voltage Switchgear and Controlgear IEC 60129 AC Disconnectors and Earthing Switches IEC 60265 High-Voltage Switches IEC 61000-4-3: 2002 Radiated RF Immunity IEC 61000-4-6: 2004 Conducted RF Immunity IEC 60255-22-4: 2002 Fast Transients Immunity IEC 60255-22-1: 2005 Damped Oscillatory Wave Immunity IEC 60225-5: 2000 Dielectric Strength Immunity IEC 60225-5: 2000 Impulse Voltage Withstand Immunity IEC 61000-4-2: 2001 Electrostatic Discharge Immunity IEC 60643-1 Surge Protection IEC 60643-12 Surge Protection ISO 9001 Quality Systems Model for Quality Assurance in Final Design, Development, Production, Installation and Servicing NEMA CC-1 Electric Power Connectors for Substations IEEE 837 Standard for Qualifying Permanent Connections Used in Substation Grounding 5
MMC-HVDC Commissioning and Factory and Site Acceptance Tests The commissioning process consists of factory acceptance tests (FATs), or offsite tests, and site acceptance tests (SATs), or onsite tests. During the commissioning process, the HVDC manufacturer, together with the representatives of the customer, verifies and demonstrates the full functionality, operation, and compliance of the procured and installed equipment according to the functional requirements and specifications. 6
Typical test programs during FAT and SAT offsite testing (e.g. components and subsystem tests including control and protection tests, auxiliary equipment tests, dynamic performance tests); verification of onsite installation; onsite HVDC terminal energizing tests; operation of the HVDC terminal in STATCOM mode; controlled start-up and shutdown tests and emergency shutdown tests; steady-state power transmission tests, including power ramping; power quality and interference tests; black-start operation and loss of auxiliary (disturbance) tests. end-to-end system tests; AC network interaction tests (e.g. grid-code compliance tests, staged faults, reactive power and voltage control tests, and run-back and protection function tests). 7
Pre-Commissioning The offsite commissioning starts with the pre-commissioning procedure. This consists of the inspection and documentation of manufactured equipment and subsystem test preparations. Subsystem tests include electrical and mechanical tests and simple functional tests confined to a subsystem. The objectives of these tests are to inspect the equipment s condition and verify the manufacturing, installation, and operation according to the technical requirements and standards. 8
Offsite Commissioning Tests or Factory Acceptance Tests Offsite commissioning tests (FATs) include end-to-end tests and verification of all subsystems, including complete HVDC control and protection systems. Normally at this stage, the high-voltage equipment and the ac networks are modeled and simulated with a real-time simulation RTS) tool. For the test actual control and protection cubicles will be wired to the RTS, and tested. The FATs should cover the steady-state operation and dynamic performance behavior of the HVDC converter during ac and dc network fault conditions. For these tests, different ac and dc network fault conditions are simulated, and the HVDC control and protection functionalities are verified and documented. 9
Onsite Testing and Site Acceptance Tests SATs normally consist of the following stages: mechanical and electrical verification of installed equipment; individual subsystem tests; single terminal energizing tests; operation in STATCOM mode; grid-code compliance tests; end-to-end power flow tests; heat run and the trial operation test. During SATs, as a minimum, the normal operation of all subsystems and the signaling between them are controlled, monitored, and documented, before high-voltage energizing tests are initiated.
Onsite Energizing Tests (1) After the approval and signoff of the onsite subsystem acceptance tests, the energizing of the HVDC terminal can be initiated. The energizing tests are normally initiated by energizing the ac switchyard and the substation transformers. The converter terminal tests constitute a set of verifications of the acbus-voltage control and reactive power control modes (STATCOM mode of operation) that are to be conducted when the converter terminal is connected to the adjacent ac network for the first time.
Onsite Energizing Tests (2) During the end-to-end tests, the following control modes should be verified: AC-bus-voltage control at both terminals; reactive power control at both terminals; DC-bus-voltage control at both terminals; DC power flow and step control response; independent control of active (P) and reactive (Q) powers at both terminals; system redundancy and changeover tests; trip tests; communication and operator control tests (e.g. transfer of HMI station and system functions between individual control locations, including local station control at both terminals).