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Figure 9.16.6 Modular type 2 surge arrester for protecting the Figure 9.16.7 Protection of the stator side of the generator
230/400 V supply

Figure 9.16.8 Coordinated type 1 surge arrester Figure 9.16.9 DEHNmid medium-voltage arresters installed in a
transformer for wind turbines

celle and the pitch system in the hub by means of a 230/400 V resters can be installed at both sides of the converter (grid
TN-C system (Figure 9.16.6). and machine side) and on the generator. Only if doubly-fed
induction generators are used, an arrester combination with
Protection of the aircraft warning light an increased electric strength must be used on the rotor side.
The aircraft warning light on the sensor mast in LPZ 0 B should For this purpose, it is advisable to install a 3 + 1 Neptune circuit
be protected by a type 2 surge arrester at the relevant zone with a nominal voltage up to 1000 V. An additional spark-gap-
transitions (LPZ 0 B → 1, LPZ 1 → 2) (Table 9.16.1). Depend- based arrester ensures electrical isolation and prevents prema-
ing on the system, e.g. components of the DEHNguard series ture tripping of the varistors.
(low voltage) and / or BLITZDUCTOR family can be used for ex-
tra low voltage / signal lines. Surge arresters for information technology systems
Surge arresters for protecting electronic equipment in telecom-
400/690 V system munication and signalling networks against the indirect and
Coordinated single-pole lightning current arresters with a high direct effects of lightning strikes and other transients are de-
follow current limitation for the 400/690 V systems, for exam- scribed in IEC 61643-21 (EN 61643-21) and are installed at the
ple DEHNbloc M 1 440 FM (Figure 9.16.8), must be installed zone boundaries in conformity with the lightning protection
to protect the 400/690 V transformer, inverters, mains filters zone concept (Figure 9.16.4, Table 9.16.1). Multi-stage ar-
and the measurement equipment. It must be ensured at the resters must be designed without blind spots, in other words it
frequency converter that the arresters are dimensioned for must be ensured that the different protection stages are coor-
the maximum voltage peaks, which are higher than in case of dinated with one another. Otherwise not all protection stages
pure sinusoidal voltages. In this context, surge arresters with a will be activated, thus causing faults in the surge protective
nominal voltage of 600 V and U mov = 750 V have proven their device. Glass fibre cables are frequently used for routing infor-
worth. The DEHNguard DG M WE 600 FM (Figure 9.16.7) ar- mation technology lines into a wind turbine and for connecting

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