Detection of harmonic occurring using Kalman filtering

As long as the load to a power system is linear which has been the case before 80´s, typically no harmonics are produced. However, the modern power electronic equipment for controlled power consumption produces harmonic disturbances, these devices/equipment possess nonlinear voltage/current characteristic. These harmonics are not to be allowed to grow beyond a certain limit to avoid any grave consequence to the customer´s main supply. Filters can be implemented at the power source or utility location to eliminate these harmonics. In this paper we detect the instance at which these harmonic occur using Kalman filter. This may be very useful for example to quickly switching on certain filters based on the harmonic present. We are using a unique technique to detect the occurrence of harmonics.