Low frequency screening effect in urban areas and the engineeringmeasurement technology

摘要

The low frequency screening effect is very good in urban districtsbecause of a lot of underground metallic pipes. There are not onlyremarkable technology-economic benefits but also society benefits whenconsidering this screening effect, which is named the city environmentscreening factor in practical engineering constructions. The theory ofthe low frequency screening effect of a multiconductor system isdiscussed in the paper. Then the engineering measurement technology andinstruments of the screening effect are introduced in detail. Somesuccessful application samples of the technology are presented. Ingeneral, the value of the city environment screening factor often can be0.5 to 0.8, the lowest value may be 0.1, the highest may be 0.8 to 0.9