Energy Efficiency Made Simple Vol IV

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

Protection of smart power grids and data

networks

T Kerchensteiner and MWiersch, DEHN+SÖHNE

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.

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.

ENERGY EFFICIENCY MADE SIMPLE 2015