UPS systems for remote or temporary telecom locations

Many requirements for UPS systems for use in remote telecommunication locations are quite clear: they must be compact, easily transportable, flexible in use and able to operate with minimum maintenance. Severe climatic and EMC requirements, both on emission and immunity, also are common. These requirements also apply to temporary UPS systems. Less clear are the special requirements that result from the generally long feeders and their associated high impedance. Any fluctuation in feeder current like surges, reactive power variations and harmonics, give larger than normal disturbances at the end of the feeder cable, and produce unacceptable dips or voltage distortion to AC loads in the telecommunication station, including to the UPS system itself. Many of these problems become significant at higher power ratings, above a few hundred kVA, when solutions like filters and batteries are less effective or difficult to install at remote or temporary sites. An alternative in the form of a containerised, diesel-powered UPS is presented