engleski

Case Study for Application of Transmission Line Arresters at Croatian 400 kV Line along the Adriatic Coast Mountains

Transmission line arresters (TLA) are commonly used to address lightning or switching related phenomena with the intent to improve the overall reliability of transmission lines. Line arresters can improve system reliability by reducing the multi-phase and multi-circuit line outage rates, or be used to help to limit switching overvoltages on EHV transmission lines rather than using closing resistors or controlled closing schemes. The majority of line arresters presently used is designed for improving the lightning performance of transmission lines and reducing the line-to-ground outage rate. Often the line performance is unsatisfactory due to its bad grounding conditions and geographical exposure while the improvement of these facts is often very costly or simply impossible. The ongoing improvement of surge arrester technology over the past 10 years on one side and the requirement of higher reliability of much higher utilized transmission lines on the other side lead to an increasing use of transmission line surge arresters for nearly all system voltage levels worldwide. Siemens as one of the biggest supplier of electrical components and solutions for power transmission has experience in manufacturing of surge arresters for more than 70 years. So Siemens consequently developed solutions for the improvement of transmission line performance using TLAs. After a brief introduction of Siemens TLAs solutions carried out in the past the paper exemplarily describes in form of a small case study how to approach a typical TLA-project. The object of the investigations will be the 400 kV transmission line from substation Melina to Konjsko, the so called southern power interconnection. It is situated in the mountains not far from the Adriatic coastline, so there are indications for partly insufficient grounding conditions as well as locally increased values of ground flash density. Moreover due to its geographical and political location this transmission line is very important for the power supply of a whole region and therefore obviously in the focus for possible enhancement of its reliability.

high voltage transmission line surge arresters; cage design TLA; transmission line reliability

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