Comparative study of harmonics reduction and power factor enhancement of six and 12-pulses HVDC system using passive and shunt APFs harmonic filters

Harmonics in HVDC power systems, which are caused by highly non-linear devices, affect its performance. Therefore, the main concern of power engineers in power system design and operation have been controlling and eliminating such harmonics. In respect of this, HVDC power system harmonic analysis is, therefore, imperative in power system planning, control and operation. It is worthy of note that, different alternatives of filter design should be considered before making final decision on filter configuration. The essence of this paper is basically to compare the mitigation techniques of both 6-pulse and 12-pulse HVDC systems using passive and shunt active power filters to eliminate line current harmonics and to compensate reactive power by increasing the power factor with reference to IEEE 519 standards. The mitigation technique of shunt active power filter is based on p-q theory. Conventionally, passive LC filters and capacitors have been used to eliminate line current harmonics and to compensate reactive power by increasing the power factor. However, these filters have the disadvantages of large size, resonance and fixed compensation behavior. Due to these drawbacks of passive harmonic filter, the shunt active power filter appears to be a viable solution for eliminating harmonic currents and current transient condition. Shunt active power filter compensates current harmonics by injecting equal and opposite harmonic compensating current. This paper concentrates on the design and application of three-phase passive and shunt active power filter (SAPF) by using p-q theory to mitigate the harmonics, which are created by nonlinear loads. To obtain result for this paper, the MATLAB / Simulink was used as a simulation tool.