Power Monitoring Device with Quantitative Harmonic Source Identification

In recent years, harmonic pollution is a growing concern with large volume of nonlinear devices applied in power systems. Those devices cause voltage and current distortion throughout the power system, which can result in reduction of efficiency of the generation, transmission and utilization of electric energy; as well as dysfunctions of power system components by interfering with relay protections and communications. Power system utilities strive to ensure that the voltage harmonic distortion planning levels are maintained by limiting the harmonic currents injected by the nonlinear loads. A power monitoring device able to quantitatively assess the harmonic contribution of a nonlinear load at one physical point called Point of Common Coupling (PCC) is envisaged as significantly promising equipment in power system engineering area. In addition, the analyzed results of such device can cast justifications in delimiting the responsibilities of the parties involved, and make it possible to build up an incentive scheme to control harmonic pollution in power systems. This paper presents a non-invasive and effective method to determine voltage harmonic emission level caused by a major nonlinear load. The method can be readily implemented on most existing power monitoring devices.