and a failure of the 220 V direct voltage control. The 20 kV surge arresters were already damaged by the initial partial lightning strikes (Figure 2.2.3
c) and, thus, the subsequent lightning strikes could no longer be dis-
charged. Sparkover arcs occurred in one switchbay (Figure 2.2.3 d) which ran along the bus bar and damaged other switchbays. Further short- circuit arcs were generated on the 20 kV overhead lines. Heavy conductor rope vibrations made the ropes glow and tear. To add further to the problems, the supplying 110 kV transformer exploded during this thun- derstorm (Figure 2.2.3 e) with the consequence that the whole town of Neumarkt (about 30 000 inhabitants) lost power for about six hours.
Figure 2.2.2.l (b) Damaged module of the printing press control
Figure 2.2.3 a Transformer substation 110/20 kV, OBAG, Neumarkt
Figure 2.2.3 b Site plan of the transformer substation 110/20 kV, OBAG,
Neumarkt
Figure 2.2.3 c Surge arresters destroyed by lightning strike
Figure 2.2.3 d Damage in 20 kV switching bays due to lightning surge
Sources
DER SPIEGEL: ‘Blitz im Atommeiler’ (1983) No. 36, p. 15
NEUMARKTER TAGBLATT: ‘Kurzschluss in Kernkraftwerk’ (22 May 1985)
2.2.4 Damage to a house
Lightning strikes into unearthed aerials of houses (without lightning pro- tection systems), such as the family house in Figure 2.2.4 a, occur fre- quently. Figures 2.2.4 b to h show the damage caused by lightning current
Figure 2.2.3 e Exploded 110 kV transformer due to lightning strike, Neumarkt, 1983
on its path of sparkovers and punctures through the electrical wiring of the house. The lightning current flows over the aerial standpipe (Figure 2.2.4 b), feeding partial lightning currents into the power system, aerial line, telephone line and water pipe. So, usually, all connected electrical appliances and the telephone system will be damaged. In the case men- tioned, the fuel oil pipe was also damaged, and oil leaked into the cellar. In a circle of radius more than 1 km, telephone systems failed due to this lightning strike; the traffic-light systems of the town were also disturbed and RC circuit breakers were tripped within a radius of about 3 km.
Figure 2.2.4 a Site plan of a house damaged by lightning, Neumarkt, 1986
Figure 2.2.4 b Damage near the antenna-pole in the loft, Neumarkt, 1986
In 1994, during a thunderstorm burst, the radio aerial of a central taxi station in Neumarkt was struck by lightning (Figure 2.2.4 i). The whole radio system was destroyed (Figure 2.2.4 j). The electrical cables and socket outlets were torn out of the walls and the entire electrical equip- ment (TV and household appliances) was damaged so heavily that it could no longer be used.
Figure 2.2.4 d Antenna line damaged by lightning strike
(a) Neumarkt 1986 (b) Similar case
Figure 2.2.4 c Punctures to concealed cables due to lightning strike
(a) Neumarkt 1986 (b) Similar case
Figure 2.2.4 e Distribution cabinets damaged by lightning strike (b) Similar case (c) Similar case (a) Neumarkt 1986
Figure 2.2.4 f Boiler damaged by lightning strike, Neumarkt, 1986
Figure 2.2.4 h Puncture from the
power line to the metal oil pipe due to lightning strike, Neumarkt, 1986
Figure 2.2.4 i (a, b) Lightning strike to the Lutter taxi central office, Neumarkt,
1994
Figure 2.2.4 g Telephone
system damaged by lightning strike, Neumarkt, 1986
Figure 2.2.4 i (a)
Figure 2.2.4 i (b)
A pressure wave smashed windows and window frames. Tiles were torn off the wall and there were cracks in the ceilings and the walls. Socket outlets were torn out of the wall (Figure 2.2.4 k). Partial lightning cur- rents were conducted along the telephone system and the power supply system, thus causing other damage in the neighbourhood (Figure 2.2.4 l). In the vicinity and wider surroundings this lightning strike caused considerably more damage than listed here. In the office of the District President, the district hospital, the inferior court, the municipal works and the abattoir, as well as in industrial and commercial enterprises, the computer systems and telephones were damaged. In the district hospital, a church, an elementary school and a museum, the safety and fire alarm systems were damaged (Table 2.2.4 a). In Figure 2.2.4 m, circles are drawn, at a separation of 1 km, around the lightning striking point (marked by an arrow). The locations of the damage are marked by bullets. Damage occurred, even at a distance of 3 km from the point of strike, for example, in the traffic-light system at the southern perimeter road of the town. The Neumarkter Nachrichten duly reported on the damage caused to telephone and cable television connections in 40 households and numerous individual TV sets.
Repeatedly, there are extended disturbances in telecommunication sectors due to solitary lightning strikes. The Hamburger Abendblatt of 12 July 1995 reported on a thunderstorm two days previously when 25 000 Telecom customers in the suburbs of Hamburg were concerned by failures of cable TV. Some 50 microchip amplifiers had to be repaired in Pinneberg, Wedel, Quickborn and Norderstedt. Underground cables damaged by lightning currents reveal high interference energies.
Figure 2.2.4 j Damaged radio system Figure 2.2.4 k Damaged
electrical lines
The reason for the above examples of damage is that electrical light- ning interferences are conducted through power and data lines from the point of strike over distances of several kilometres directly to the inputs of electronic systems and equipment (Figures 2.1 c and 2.2.4 n). Tele- phone systems, for example, are used in data processing and alarm systems, making them susceptible.
Sources
NEUMARKTER NACHRICHTEN: ‘Blitzschlag zerfetzte Leitungen und hob den Dachstuhl’ (2–3 Aug.1986)
NEUMARKTER NACHRICHTEN: ‘Unheil mit einzigem Blitzschlag’ (3 May 1994)
HAMBURGER ABENDBLATT: ‘Kabelfernsehen: Vom Blitz getroffen’ No. 160 (12 July 1995)
Figure 2.2.4 l Lightning damage (at Telekom systems) in the surroundings of
the point of strike
Table 2.2.4 a Consequences of a lightning strike to the Lutter Taxi Company Neumarkt, 1994
Table 2.2.4 a continued –
Figure 2.2.4 m Lightning damage in a radius of 3 km around the point of strike