Intelligent Relay Coordination on Motor Control Centre (MCC) (Case Study: Indorama Petrochemical Company)

Abstract

The protection of motors in Motor Control Centres (MCCs) is of key importance in industries since motors play a vital role in production processes. Any damage to them as a result of fault can halt the production process. In order to protect the motors from these faults, relay coordination has to be performed so that protective devices can properly discriminate against fault current within the fastest possible time. For this undergraduate project, ETAP software was used to design the SLD of the MCC Network, specify equipment parameter, perform load flow, short circuit analysis and protection coordination study. Manual calculation of relay TDS and Pickup setting was done. The result of this calculation was inputted into the relay properties on ETAP. After fault insertion miscoordination was observed. Time-Current Curve, TCC fitting was resorted to, it was observed that the system became coordinated after fault insertion. The sequence of operation when using calculated values of TDS and pickup to perform relay coordination and TCC curve fitting was compared. In conclusion by using TCC fitting, relay coordination can be performed by varying only the TDS values while leaving the pickup values unchanged in order to avoid nuisance tripping.