Calculation and Measurement of Electromagnetic Fields

A man is exposed to electromagnetic fields in his environment. Electromagnetic fields always exist in nature – atmospheric static electric field, the Earth's magnetic static field, the fields of a wide range of frequencies due to the outbreaks in the atmosphere, etc. However, a man is today the most exposed to the artificial field, due to progress in technology and widespread use of electrical devices. Currents, induced by electric field of surface charges are the greatest if external electric field is parallel to the length of the body. Magnetic field induces a currents inside the body as well. Variable magnetic field acting by force on charged particles in the body and creates eddy currents according to Faraday's law. Such induced currents in the low frequency area can stimulate electrically excitable tissues, such as nerve and muscle fibers, through the mechanism of action potential triggering. The area of occupational exposure includes people who are exposed to electromagnetic fields in known circumstances during usual performing of work tasks in and around power facilities, but they are educated to take protective measures and they have all the tools and instructions provided. These people are aware of potential risks and take appropriate protective measures. The environment around the power facility falls within the area of increased sensitivity, which includes people of different ages and health conditions, including those particularly sensitive. In many cases people are not aware of exposure to electromagnetic fields and can not be expected to take protective measures to reduce exposure. Therefore, the restrictions for that area are stricter than those for area of occupational exposure. The most efficient way for reliable operation of the devices in high voltage substation is the calculation and measurement of low frequency electromagnetic fields in the substation, together with appropriate measurement procedure. Contemporary research of electromagnetic fields is based on the concept that complex theoretical research results in appropriate design solution, and developes almost exclusively as applied research. Generally, there are two directions; the first one based on calculation model development, and the second one based on models of objectivized physical measurements in hard conditions. In both cases, the goal is the same and can be summarized as follows: create the