Reliability of HVDC Cable Systems for the Exploitation of Renewable Energy Sources系列讲座：Ageing and lifetime of HVDC cable systems

讲座名称： Reliability of HVDC Cable Systems for the Exploitation of Renewable Energy Sources系列讲座：Ageing and lifetime of HVDC cable systems
讲座时间： 2019-03-22
讲座人： Peter Morshuis
形式：
校区： 兴庆校区
实践学分：
讲座内容： 讲座题目：Ageing and lifetime of HVDC cable systems 讲座时间：2019年3月22日 10:00-12:00 讲座地点：East Building I North Meeting Room 讲座人：Peter Morshuis 讲座简介： Introduction The attention given to high voltage direct current (HVDC) cables appears to be at an all-time high. There are several reasons for this, one of the most important probably being the worldwide attention on harvesting renewable energy at a scale the World has never seen before. The prices of building large offshore windfarms in Europe as reflected in a recent normalized cost of electricity have unexpectedly dropped in the last years, which will further accelerate the development of HVDC cables to link offshore and onshore substations. The winning bid in 2016 for the Borssele II, 700 MW offshore windfarm in the Netherlands was as low as 54.5€ (US$61)/MWh, making the price comparable to energy produced by classic coal fired power plants. Perhaps the strongest drivers now are the developments of high power HVDC corridors on land in Germany and China. In Germany a large amount of offshore wind generation needs to be integrated into the grid, requiring a 525 kV corridor from North to South (Südlink). A very substantial part of this corridor will be realized with underground HVDC links because of the low public acceptance of overhead power lines. TransnetBW GmbH has estimated that Germany will require new HVDC transmission corridors with a total length of between 2,600 and 3,100 km and with a total transmission capacity of 12 GW. While many HVDC subsea systems have been installed successfully, such underground systems on land pose considerable challenges, many of which relate to the choice of insulation system within the HVDC cable. In China the developments in the field of HVDC are further speeding up. In 2016 there are some 22 HVDC transmission systems commissioned or in operation, including the ±800 kV Shanghaimiao-Shandong HVDC project with a planned transmission capacity of 10 GW. In May 2017 the Chinese president Xi Jinping announced further details about the One Belt One Road policy, including energy corridors connecting China and Europe. In addition, strategic projects are being planned to interconnect Asian countries. The decisions to transport electrical energy over very long distances will naturally lead to increasing voltage levels. A substantial part of the HVDC corridors will have to be installed underground, using HVDC cable technology. While major cable and cable insulation manufacturers are developing polymeric HVDC cables for higher and higher operating voltage [640 kV cross-linked polyethylene (XLPE), 700 kV MI-PPL], the question remains how far we can go with pushing the current technologies to even higher voltage levels. The lectures This short series of lectures therefore sets out to make students aware of the challenges we are faced with globally (the bigger picture) in creating a reliable and environment friendly HVDC grid, and from there move on to more specific problems. Although the focus of the lectures is on HVDC cable systems, the general approach is also valid for other components in an HVDC grid. The lectures will introduce the students to the main differences between designing for DC and AC. It will be described how and why space charge, temperature and operating conditions have such a pronounced effect on the design. The main ageing and failure mechanisms under DC voltage will be reviewed and their relation with testing techniques will be elucidated. How to design a testing strategy will be a major point of attention. Finally, the operation of HVDC cable systems is discussed in terms of economics (how to get most energy transported) and long time reliability (how to ensure an availability of the systems for 30 years). Many of the topics presented in these lectures are very relevant right now, and they will become even more relevant in the near future. By the end of this series of lectures you should have become fully aware of the challenges and you should have (part of) the background and the tools to help the HVDC future. The lectures will be taught in English by someone with an entirely different culture. One of the intentions is to bridge the different cultures and create an atmosphere in which there is not only a transfer of knowledge but also an exchange between students and professor. This will be a challenging and hopefully exciting process. Topics: ·         Introduction to HVDC ·         Global and Chinese developments in HVDC ·         HVDC and the exploitation of renewable energy sources o    Offshore wind energy o    Long distance interconnections o    Sea versus land ·         HVDC insulation basics o    Electric fields, polarization and space charge o    The importance of temperature ·         Basic design of HVDC insulation systems ·         Space charge o    Mechanisms o    Measurement ·         Aging and lifetime of HVDC insulation systems ·         Performance optimization of HVDC components ·         Testing, statistics ·         On-line monitoring ·         The main challenges in the field of HVDC Learning goals: ·         To know the main application areas of HVDC ·         To be able to explain why HVDC is important for the large-scale exploitation of renewable energy sources ·         To know how an insulating material responds to the application of a DC voltage ·         To know the difference in behavior between AC and DC stressing of an insulating material ·         To be able to explain the importance of temperature under DC ·         To know the operating conditions of HVDC components and how they affect the insulation ·         To be able to make a basic design of an HVDC insulation system ·         To understand how space charge may affect the behavior of HVDC insulation systems ·         To understand the basic mechanisms leading to space charge accumulation ·         To know the main aging and breakdown mechanisms under DC ·         To understand which factors affect the lifetime of HVDC insulation systems ·         To be able to make a basic design of a testing procedure of HVDC components ·         To understand how on-line monitoring can be used to optimize performance and availability of HVDC components ·         To know the main challenges in the field of HVDC Prior knowledge required: ·         Electric fields under AC ·         Basics of high voltage AC components ·         AC aging and breakdown Reference (If any): 1.   Book: Industrial High DC Voltage, F.H. Kreuger (PDF “hand-out”) 2.   Various literature (PDF “hand-out”)
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