IEEE 1692:2011 pdf free download

IEEE 1692:2011 pdf free download.IEEE Guide for the Protection of Communication Installations from Lightning Effects.
Fault current blocking through automatic ac disconnect isolation requires protected equipment to have power back-up systems such as battery, uninterruptible power supply, or battery/generator equipment for uninterrupted operation during ac isolation. AC service is automatically reconnected after the threat has subsided below an acceptable threshold.
AC isolation periods for LGPR will nominally be several minutes but are automatically extended if the LGPR threat condition persists. Isolation periods for power line tult conditions will be several seconds. but also extend if power line conditions do not return to acceptable levels. AC isolation will respond to power line sags, swells, and short term transients exceeding threshold levels.
Effective ac disconnect isolation requires preemptive detection of impending LGPR events. Detection of LGPR from approaching storms and of rapidly changing local surface electric fields provides the indications of imminent threat.
There is no means to predict power-related fault conditions. AC isolation will minimize the stress caused by extended poor ac power quality. AC power is reconnected to the protected equipment after it stabilizes within selected thresholds. As a result, the site is not exposed to power recovery transients following a power service failure.
7. Locating (siting) towers
Design engineers attempting to keep transmission losses low, along with the real estate considerations. usually dictate that the equipment building be as close to the antenna tower as possible. This practice goes against the design of a reliable and robust equipment system to lightning.
The recommended minimum distance between the equipment buildings associated with nearby antenna towers is (9 m [30 feet]) in order to minimize the effects of the electromagnetic field associated with lightning and to reduce the risk of damage to equipment circuits. In general. electromagnetic field strength drops off as the square of the distance. if real estate considerations prevent the building from being more than 9 m (30 feet) from its antenna tower, then a Faraday cage (wire mesh) around the interior of the building should be csiablished. Without a Faraday cage, equipment damage cannot be prevented no matter how well the equipment is grounded or isolated from remote earth.
The recommended minimum distance between the equipment buildings and the towers also contributes to keep the LGPR at the tower base from saturating the building grounding system, before a majority of it can be dissipated.
The two grounding electrode systems (for the tower and for the equipment building) must be bonded together at one single point. However, a bond of 9 m (30 feet) or more will significantly reduce the resulting GPR at the equipment building due to the impedance of this lengthy bond. This is one of those rare exceptions in which a lengthy bond is an advantage in supporting a robust grounding system to lightning.