Active filter design and testing for electrical networks

The increasing use and diversity of electronic devices brings with it some problems. The waveform of the electrical signal coming from the electricity distribution networks is sinusoidal. The electrical energy used by electronic devices must be used in a lossless or distortion-free manner as it comes from the distribution network. Unbalanced loads on the electrical system create harmonic effects and cause disturbances in the sinusoidal shape of the electrical network. Harmonics occur especially due to the increased frequency of use of semiconductor power electronic circuit elements brought by today's technology. Especially in industrial facilities and business centers, the use of devices that draw harmonic current requires solutions such as active filtering. If the harmonic effects are not eliminated in some way, they can damage both the network and other loads on the network. Filters are used to suppress or eliminate the distortion in electrical energy against the damaging harmonic effects caused by loads. Filters are of active filter and passive filter type and should be designed according to the network in which they will be used. The filters to be designed must comply with the limit values determined in accordance with internationally accepted standards and regulations. The aim of this thesis is to reduce the harmonics caused by unbalanced and semiconductor based loads in electrical networks to the level accepted by the standards by designing and testing active filters or hybrid filters. In the study, the energy flow of the 7th block located in Haliç University 5th Levent Campus was measured with energy analyzers, the data obtained was converted into a form suitable for analysis, active filters were designed separately for current and voltage with Matlab/Simulink, and a passive filter was designed and added to the system according to the test results in order to provide more efficient results of the filters obtained. As a result of the measurements made, according to IEEE-519-2022, the individual harmonic should be 5% or less at voltages of 1kV and below, while it was 0.5% in our study. For current values, according to the IEEE-519-1992 standard, the ISC/IL ratio should be in the harmonic level range between 2...11, while in our study, this ratio was maximum 3.88. The results of the study, FFT analysis and QuickField application were then compared and it was understood that the THB value was in accordance with the standards.