One of the windings is connected in star and the other in delta. Converter transformer an overview sciencedirect topics. Guide to high voltage direct current hvdc transmission on photo. Abb has delivered more than half of the worlds hvdc projects. High voltage dc converter transformer is the main component which is used in hvdc transmission. High voltage direct current transmission notes pdf hvdc. This paper explains design considerations for lead and leadexit insulations of hvdc converter transformer for the purpose of automated design optimization. Pdf this paper presents a reliability assessment of the hvdc converter transformer system cts. Reliability of hvdc converter transformers is of paramount importance, especially for lcchvdc systems 6. Design of power converters for hvdc applications eep. Recently new applications have been found, most prominently the interconnection of large offshore windfarms to onshore grids. Converter transformer energization 400kvac side hvdc.
Abb library is a web tool for searching for documents related to abb products and services. Typically, the this ac harmonic current flow can link with adjacent converter transformer is arranged as an earthed kaamkshaiah conductors, such as openwire telecommunication winding and a floatingstar and delta secondary windings. Graetz circuit is the best circuit for a six pulse converter. Optimization of lead insulations for hvdc converter.
The converter transformers at both converter stations of dc transmission projects are fitted. For long distance transmission of power, hvdc transmissions are more economical than ac. An hvdc converter converts electric power from high voltage alternating current ac to highvoltage direct current hvdc, or vice versa. There is much to be gained from removing the transformer. Hvdc classic converter transformers up to 12 gw gigawatt and 80 kv 1,100 kv direct current dc and 1,200 kv alternating current ac hvdc light converter transformers up to 1,500 mw and. Experience and ingenuity are what made this development possible. As the voltage changes can be sudden, it is obvious that manual control of converter. Developments in uhvdc and uhvac transmission english pdf white paper ultra high voltage power transformers english pdf brochure. Yny0d 400v3 207,7v3 207,7 kv impedance 12,0 % cooling ofaf y winding on high dc level d winding on low dc level y and d connections inside valve hall transformer in sctesting at kema holland the only large hvdc transformer ever sc tested transport weight 230 ton.
Siemens delivers hvdc plus converter transformers for transmission lines up to 1,200 mw, up to 500 kv dc with connections to ac grids up to 525 kv. Developments in uhvdc and uhvac transmission english pdf white paper ultra high voltage power transformers english pdf brochure hvdc converter transformers english pdf brochure a remarkable journey transportation of the worlds largest hvdc transformers english mpg movie. Hvdc converter transformers power transformers abb. Hvdc converter an hvdc converter converts electric power from high voltage alternating current ac to highvoltage direct current hvdc, or vice versa. Supply of ac voltages into two separate circuits feeding the rectifier bridges with a phase shift of 30 electrical. Siemens at that time, conversion between reasonable consumer voltages and higher dc transmission voltages could only be.
Converter transformer ratings type of converter transformer. The transformer accounts for a significant amount of the total terminal costs and losses. Hvdc power transmission an overview sciencedirect topics. Kortslutningssakra transformatorer enligt iec 600765. High voltage dc hvdc transmission linkedin slideshare. For this conversion, converter transformer is get used. Hvdc classic converter transformers hvdc converter. Hvdc converter transformers for remote energy transmission. Thus a 12 pulse converter is obtained by the series connection of two bridges. Consequently, the ac voltages applied to each 6pulse valve group that makes up the 12pulse valve group have a phase difference of 30 degrees that is utilized to cancel the ac side, 5th and 7th harmonic currents, and dc side, 6th harmonic voltage. As all generating stations are generating power in ac, we are in need to convert this ac to hvdc.
On the ac side of a 12pulse hvdc converter, current harmonics of the order of 11, 23, 25 and higher are generated. Components of hvdc high voltage direct current capacitor. In the beginning all hvdc schemes used mercury arc valves, invariably. It is a bulky unit, which in some cases presents a logistic problem. Power transformers hvdc transformers building trust. Good question, let me explain you, being a hvdc engineer. Pdf availability assessment of the hvdc converter transformer. Hvdc transformers are used for selfcommutated voltagesourced converters.
In addition to the converter, the station usually contains. Nearly all hvdc power converters with thyristor valves are assembled in a converter bridge of 12pulse configuration, as shown in fig. Design, control and application of modular multilevel converters for hvdc transmission systems is a comprehensive guide to semiconductor technologies applicable for mmc design, component sizing control, modulation, and application of the mmc technology for hvdc transmission separated into three distinct parts, the first offers an overview of mmc technology, including. An hvdc converter station or simply converter station is a specialised type of substation which forms the terminal equipment for a highvoltage direct current hvdc transmission line.
Design considerations for those insulations are the. With this arrangement the dominant harmonics from the converter will be cancelled out. Converter transformer single phase 194 mva 3 winding transf. As a galvanic barrier between ac and dc systems to prevent. Abb designed, manufactured and tested the worlds largest hvdc converter transformers for the project. Abb and hvdc the worlds first commercial highvoltage direct current hvdc link, situated between the swedish mainland and the island gotland, was delivered by abb already in the 1950s.
A monopolar hvdc system with ground return consists of one or more sixpulse converter units in series or parallel at each end, a single conductor and return through the earth or sea, as shown in figure 2. The worlds first hvdc transformer passes the test for. It converts direct current to alternating current or the reverse. Converter transformer is the combination of converter and transformer. Hvdc transmission systems unit1 introduction electric power transmission was originally developed with direct current. Furthermore, abb has designed and manufactured more than 350 hvdc converter transformer units in the 801,100 kv dc voltage range. Our extensive experience helps us deliver outstanding value to customers worldwide. The converter transformers at both converter stations of dc transmission projects are fitted with onload tap changers in order to ensure the rated optimum firing angle of converters under normal operation of the dc system. Hvdc is used as an alternative to ac for transmitting electrical energy over long distances or between ac power systems of different frequencies. Hvdc classic transformers are the heart of hvdc transmission systems. Pdf power electronic onload tap changer for hvdc converter. Markus pettersson, september 22, 2016 plnabb power.
Hvdc converters capable of converting up to two gigawatts gw and with voltage ratings of. In hvdc transmission, the series conduction of converter groups has been preferred because of the ease of control and protection as well as the requirements of high voltage rating. High voltage direct current hvdctransmission systems. Guide to high voltage direct current hvdc transmission. A hvdc converter transformer should at least deal with ac, dc, and dc polarity reversal stresses, which complicate designing process of insulation structures. Single phase three windings rated power of line star delta winding mva.
Hvdc converter transformers are the heart of hvdc transmission systems. Principles of hvdc controls control of dc voltage dc voltage is varied by means of a converter bridge in rectifier operation the power flow is from the ac system to the dc system the power flow is changed from the dc system to the ac system by reversing the dc voltage. Converter transformer energization during commissioning of the hvdc back to back 220kvdc3x600mw. The availability of transformers and the development and improvement of induction motors at the beginning of the 20th century, led. What is the difference between a converter transformer. To secure the reliability of power, the first major hvdc link in the us was installed. Abb has participated in the delivery of more than half of the worlds around 170 hvdc links. The owners of the celilo converter station decided to refurbish and upgrade the station capacity to 3,800 mw. Historically the main use of high voltage direct current hvdc systems has been the bulk transmission of power over long distances and interconnecting neighbouring asynchronous ac systems. The converter transformer is generally built with two valve windings see fig.
The operating range of the ideal converter theory from. High voltage direct current transmission pdf notes hvdc. Hvdc converter transformers guidelines for conducting. In hvdc plus monopole applications, no dc voltage stresses occurs at the transformer valve terminals. These two transformers are almost same design except 1. The high voltage direct current transmission notes pdf hvdc notes pdf book starts with the topics covering types of hvdc links, choice of converter configuration, converters control characteristics, reactive power requirements in steady stateconventional control strategies, dc networkdc converter, generation of harmonics, characteristics.
Abb successfully developed and tested 1,100 kv converter transformer technology breaking the record for the highest dc voltage levels ever. The worlds largest hvdc converter transformers provided to. Threephase voltage source converter hvdc terminals are normally equipped with a full transformer. Most hvdc converters of today are linecommutated 12pulse converters. Supply of ac voltages into two separate circuits feeding the rectifier bridges with a phase shift of 30 electrical degrees for reduction of low order harmonics esp. The converter transformers are designed to withstand dc voltage stresses and.
998 803 1283 1162 435 707 920 42 1309 322 1331 896 876 1364 607 34 158 1465 394 70 1072 294 1507 373 63 1092 594 615 74 1583 639 883 978 851 759 729 931 1289 747 360 584 1093