A controllable distributed energy resource with active filtering capability based on online harmonic detection

In this paper, an effective method for harmonic compensation in an AC distribution system is proposed and investigated based on the instantaneous power (p-q) theory. The distributed source is interfaced to the grid through a power electronic (PE) converter, called as a controllable distributed energy resource (DER). It has been investigated that such kind of configuration can be successfully applied to address power quality issues in a distribution system. The controllable DER, not only provides some part of active power to the non-linear load in its vicinity, it also tries to alleviate harmonic problems in the source current. A detailed simulation analysis is carried out under different conditions and it has been confirmed that controllable DER effectively provides active power filtering. When using the controllable DER as a switching compensator only, it provides the best performance. On the other hands, when it contributes active power to the load the total harmonic distortion (THD) in the source current is less improved because some part of the non-linear load current is shared by the DER sinusoidal current.