Case study # 2.3 Title Damage of LD-SLT and DCS telecommunication equipment Type of trouble Damage. Source of trouble Lightning. System affected Transmission equipment. Location Telecom centre. Keywords Damage, lightning surge. Version date 2004-01-01 System configuration A system configuration and an estimated current flow are shown in Figure 2.3-1. This telecommunication centre is a co-location building. Company A's telecommunication equipment and another company's equipment are sharing one same floor of the building. The radio equipment is connected to the antennas as shown in Figure 2.3-1. The power supply equipment located on the first floor is used to distribute DC power to both companies' telecommunication equipment. IBS in the figure is a DC power distribution module. Company A's telecommunication equipment is powered through the IBS, while the other company's equipment is powered through the PDF, where PDF and IBS are power distribution frames. The PDF and IBS are also connected to the RF located on the first floor. DCS is a clock-supplying equipment that provides the clock signal to the radio equipment CR-822. CR-822 has a telecom interface and is connected to the switching equipment LD-SLT through a DF (a distribution frame). At this telecom centre, LD-SLT, SLM, DCS, and PSF were damaged by lightning. 3F Company A Other company PDF PSF CR-822 Transmitter-receiver DC+ antenna LD-SLT IBS DF DC+ DC+ Yagi antenna DF G SLM SR-4 Line DCS DC+ CLK line MDF Telecom cables 1F 2F RF SR-4 200 V 40-ARR Miti(08)_F2.3-1 E0 E3 EMDF Figure 2.3-1 – A system configuration and an estimated surge current Copyright © ITU 2010 – All Rights Reserved