Low Frequency Screening Effect in Urban Areas and the Engineering Measurement Technology

摘要

The low frequency screening effect is very well in urban districts because of a lot of underground metallic pipes. It can bring remarkable not only technology-economics but also society benefits considering this screening efffect that is named city environment screening factor in the prequency screening effect of multiconductor system is discussed at first in the paper. Then the engineering measurement technology and instrument of the screening effect are introduced in detail. Some successful application samples of the technology are presented. In general, the value of the city environemnt screening factor often can be 0.5 to 0.8, the lowest may the 0.1, the highest be 0.8 to 0.9.