Energy Efficiency Made Simple Vol IV 2015

If it is in sub-Saharan Africa, and if it is electrical, lightning poses a risk. New energy technologies, covering large geographic areas, have posed challenges to lightning protection specialists to find better solutions with appropriate levels of protection. These challenges are exacerbated by the increasingly networked and sensitive nature of many of the new energy technologies.

Protection of smart power grids and data networks T Kerchensteiner and MWiersch, DEHN+SÖHNE

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H igher demands are being placed on technologies owing to political framework conditions and particularly the increasing complexity and wide distribution of the individual systems. New topics, such as smart grid, smart metering or smart home, require innovative solutions. The rapid rise of distributed, renewable energy sources in combination with centralised power stations, energy storage systems and intelligent technologies requires a reliable and coordinated overall lightning and surge protection system. Germany’s transition to sustainable energy involves a variety of measures. In this context, it is particularly important to keep the three objectives of energy policy (environmental compatibility, cost-effec- tiveness and supply reliability) balanced. Supply gaps quickly cause enormous economic damage and the rapid development in the energy sector inevitably results in higher demands on technologies. This does not only affect power generation and transmission networks, but also distribution network structures where 90% of the transition to sustainable energy takes place [1]. Although the reliability of power In future, the structures for power generation, transmission and distribution in the high, mediumand low-voltage rangewill bemore complex and flexible than they are today.

supply is constant in Germany, voltage control pushes network operators and municipal utilities to their limits owing to the increasingly distributed infeed from renewable energy systems into low-voltage and medium-voltage networks. To ensure permanent grid stability, voltage control is now implemented by transformer substations instead of large power plants [2]. Sources of damage and protection standards There are various sources of damage for surges. According to the IEC/EN 62305-2 [3] standard, the causes of surges in case of lightning discharges can be sub-divided into four groups depending on the point of strike (see Figure 1 ):

• Direct lightning strike to the structure • Lightning strike next to the structure

• Direct lightning strike to the incoming supply line • Lightning strike next to the incoming supply line

Today it can be considered certain that the radius of destruction around the point of strike is more than two kilometres owing to, for example, highly networked power grids and data networks. In addition, surges are caused by switching operations, earth faults and short- circuits or tripping fuses, Switching Electromagnetic Pulse (SEMP). To minimise damage caused by lightning effects, the following solution

Figure 1: Causes of surges in case of lightning discharges in the power supply system.

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ENERGY EFFICIENCY MADE SIMPLE 2015