M. Tech. Electrical Engineering. / This dissertation presents an effective method to determine current/voltage harmonic emission levels caused by various devices in the network. The method is implemented based on the existing power monitoring devices installed in power generation plants. The Digital Fault Recorders (DFRs) are used in this work as the monitoring devices. Due to the advancement of data processing and communication capabilities of such devices, a large amount of information generated by DFRs is concentrated in the utilitys head office. This data is archived for permanent storage and analysis. The presented work aims to assist the power utilities in harmonic invigilation problems based on DFRs.