Loboda Y. Control system of static reactive power compensators in asymmetric non-sinusoidal modes of distribution networks

The thesis sets and solves the urgent task of errors reduction in balancing the currents of return and zero sequences together with the compensation of higher harmonics in asymmetric non - sinusoidal modes of distributive electric networks. The scientific novelty of the obtained results and the provisions submitted for the protection implies for the improvement of the control system of static compensators of reactive power in electrical distribution networks by forming instantaneous sinusoidal currents of reverse and zero sequences. The following scientific results were obtained in the work: 1. For the first time there had been substantiated the method of direct current control of static synchronous compensator with the formation of non-sinusoidal signals equal which equal the difference in currents of the of the phases loading and their main harmonics and sinusoidal asymmetric signals, respectively, for the compensation of higher harmonics and balancing of load currents, that allows to ensure the segmentation of controlling filtering contours of the higher harmonics and balancing the nonlinear asymmetric loads. 2. There had been improved the method for controlling the static thyristor compensators with the use of conditional powers of the reverse sequence and the corresponding currents in the dq-coordinate system, which provides for an increase in their accuracy and responce in the presence of asymmetric consumers. 3. The method of controlling static synchronous compensators with the use of instantaneous symmetric currents of the reverse and zero sequences has been further developed, which provides for the reduction of dynamic errors in the balancing of load currents.