Passive filter design for weak distribution system with 24-pulse converter load using EMT models

The article deal with harmonic distortion in distribution network because of a huge 2 x 5.5 MW load (motors) is supplied by 24-pulse rectifier, dc line and convertor. The EMT model of the network for harmonic distortion evaluation was assembled. Values of THD, TDD and individual harmonic content were computed, and the results were compared with technical standards (IEEE-519-2022 and IEC/TR 61000-3-6.). Some configurations of distribution network with underground cables and overhead lines were tested and the worst cases were found. The evaluations of EMT computation results of that cases according to standards lead to a decision for passive filter installations. The further investigation was focused to find proper passive filter scheme, and parameters of RLC elements. The aim of investigation is the best filters efficiency to mitigate harmonics with minimum of reactive power consumption and power losses for the fundamental harmonic component (50 Hz). Some types of filters and its combinations were designed and tested in EMTP models with the aim to find the best of them.