Heydari - Center of Excellence for Power System Automation and Operation Iran University of Science & Technology, Iran
Abbasi - Center of Excellence for Power System Automation and Operation Iran University of Science & Technology, Iran
Faghihi - Center of Excellence for Power System Automation and Operation Iran University of Science & Technology, Iran

High performance and correct jicnctionality of equipments that operating in high voltage substations during transient states need careful and engineering design. These are some purrs of electromagnetic compatibility studies in substation as an electrorrzugtzetic environment. To achieve electrornagnetic conzpatibility in a system the first step is to have some correction in design and second is some special methods like shielding, grounding and filtering witch cause increasing in overall cost. In this paper we study a medium voltage substation that switching process in it cause electromagr~etic intetjkmce to low voltage cables. Three n7etlzods of decreasing oven$oltage and overcnrrent are disc~lssed and comnpared. Recognition of magnetic fields is accomplished by ANSYS (base on finite element method). Then overvoltages during switching process are calc~ilated by common mode and difSerentia1 mode eqcrivalent circuit.

Electromagnetic Compatibility, Electromagnetic Interference, Switching, Substation, Cable