Energy Efficiency Made Simple Vol IV 2015

it frequently leads to long operational interruptions. Consequential damage and the costs for clarifying liability issues are sometimes considerably higher than the actual hardware damage [7]. Numerous dif- ferent lightning and surge protection components are available for preventing such damage in smart grids depending on the relevant requirements. In this con- text, it is important to consider all potential points of injection, namely both power supply and information technology and communication systems. Space-sav- ing and powerful arresters with CI technology and Lifetime Indication can offer additional benefits. To achieve a consistent and functioning surge protection concept, energy coordination between the arrester types according to IEC/EN 62305-4 must be ensured. To complement surge protection and to ensure a complete and comprehensive protection system, an external lightning protection system (air-termination system, down conductor and particularly earth-termi-

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must be protected accordingly. The same applies to the transmission systems with external antennas which are only exposed to surges resulting from the field of the lightning channel [5]. A practical solution for the direct installation of protective devices into intelligent transformer substations which considers the possible threat potential is, for example, a complete system for measuring, control and telecontrol systems in a single enclosure (see Figure 2 ). This application includes, for example, network analysis, integration of electronic meters, short-circuit indicators and communication devices. To ensure the required availability, the system in a compact enclosure is protected from surges by adequate arresters. This is achieved by DEHN surge arresters for power supply systems and arresters which are specifically designed for use in wire- less-applications for coaxial device and antenna interfaces (available with SMA, BNC or N-connection for bushing installation). Since only surges are to be expected due to the restrictions described before and the secondary technology is directly integrated in an intelligent transformer substation, Type 2 and Type 3 arresters are sufficient in this case. In this particular application for protecting the secondary technology in an intelligent transformer substation, the neutral point of the transformer is directly earthed in addition to the surge protection measures mentioned. This clearly differentiates the place of installation ‘substation’ from other places of installation since possible interference impulses on the low-voltage side of the system are discharged via the earthed low-impedance neutral point of the transformer. In addition to theoretical considerations, practical tests of such overall systems can be performed in DEHN’s in-house test laboratory [6]. Conclusion Since the energy and data landscape is becoming increasingly complex and highly networked, the probability of damage to electronic equip- ment caused by electromagnetic interference significantly increases. This is due to the broad introduction of electronic devices and systems and their decreasing signal levels (and thus increasing sensitivity). Even though destruction of electronic components is often not spectacular, DEHN surge protective device for power supply, information technology and communication systems.

nation system) should be additionally installed and safety equipment should be worn in the intelligent transformer substation. An important topic is, for example, the correct dimensioning of earth-termination systems for transformer stations with respect to the current carrying capability and corrosion, which are described in separate papers [8, 9]. Such an overall protection system meets the increasing demands the industrial society places on a stable and reliable power supply. They require highly available distribution networks with minimum downtime, thus ensuring increased supply reliability and availability. References [1] Wiersch M. Surge protection for smart grids – High system availability as well as safe and trouble-free operation. Ew volume 114 (2015), H. 1. [2] WAGO Kontakttechnik GmbH & Co. KG, Minden: http://www. wago.de. [3] DEHN + SÖHNE. Lightning Protection Guide, 3 rd updated edition, July 2013. [4] Forum Netztechnik/Netzbetrieb im VDE (FNN): Substations – Recommendations for dimensioning, installation, retrofitting and operation. Berlin, 2013. [5] DEHN + SÖHNE GMBH + CO.KG.: Intelligent substations - Surge protection for the secondary technology in intelligent transformer substations. Neumarkt, 2012 [6] DEHN + SÖHNE GMBH + CO.KG. DEHN tests and analyses – DEHN test centre (brochure No. 113). Neumarkt, 2014. [7] Landers, EH. Zahlmann, P. EMC - Lightning protection for electri- cal and electronic systems within structures. VDE Verlag GmbH, Berlin, 3 rd edition. 2013. [8] Biebl, P, Seitz, T, Pfister, N. Dimensioning of earth-termination systems for transformer stations with regard to the current carrying capacity and corrosion. netzpraxis. volume 50 (2011). Issues 3 and 4. [9] Müller, KP. Corrosion damage on earthing systems Elektroprak- tiker. Edition 9. 2010. HUSS-MEDIEN GmbH Berlin.

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ENERGY EFFICIENCY MADE SIMPLE 2015