Resonance in Electrical Power Systems of Petrochemical Plants

Abstract

One of the most serious problems in the operation of petrochemical plants is the breakdown of the electrical energy in the production processes. This interruption could be due to the presence of failures that inhibit the continuity and reliability of the electrical energy service. A possible cause of fault in the electrical power system with permanent damages in the primary electrical equipment is the occurrence of the electromagnetic resonance phenomenon. The presence of this phenomenon is directly associated with the grounding scheme of the electrical power equipments. At the moment, in some petrochemical plants only one neutral is connected to ground. When a fault appears, the protection relays operate in order to release the fault and leaving the system temporarily without ground reference. During this time the electrical system remains floated the resonance phenomenon can appear. In petrochemical plants, it is a common practice to have a neutral bus where all the power equipments are connected through an energy cable with a length up to 1 km, with a parasitic capacitance in the order of 50 to 1,000 nF.