Study on optimal harmonic energy harvesting from non-linear loads within enterprise buildings

Increasing penetration of non-linear loads, results in lines carrying harmonic currents in addition to the fundamental frequency current. Harmonics cause increased losses in distribution system components and malfunctioning of certain sensitive loads. The problem is generally addressed by installing passive or active harmonic filters. However, rather than just suppressing them, if filter configurations are modified to harness energy associated with harmonics and utilize it for suitable applications, the cost of filter installation can be paid back. This paper proposes a concept of harvesting energy associated with dominant harmonic frequency component of sites having non-linear loads and utilize the energy for supplying heating loads present within the same premises. To harness the dominant harmonic energy, a tunable filter with harvesting load and a variable resistor is dynamically tuned to the harmonic frequency having dominant power at that instant. The paper also describes the possible filter configurations which can be utilized to harness the energy according to spectral components of the non-linear load present within the facility. Apart from harmonics, possibility of harvesting energy associated with other spectral components such as inter-harmonics and sub-harmonics is also discussed. To test the possibility of harvesting harmonic energy available in enterprise buildings a test site with predominantly computer/printer and HVAC load is considered and analyzed.