Sources of electromagnetic emission

For years the Electricity Supply Industry has been accustomed to ensuring that control and protective relays have sufficient immunity against electromagnetic interference to ensure safe and correct operation. In recent years the increased use of sensitive electronic equipment within a substation has highlighted the importance of electromagnetic emission control and immunity. The primary sources of interference, which may affect auxiliary systems in electrical supply systems, can be either transient or continuous emissions. The author describes a number of transient and continuous emission sources