Lavshonok A. Selective protection against single-phase short circuits on ground in radial electrical networks 6(10)кV

Object - underground high-voltage electrical network together with means of protection from single-phase short circuits on ground; the purpose - increase of efficiency of operation of radial electrical networks by a voltage 6 (10) кV at the expense of perfection of ways and means of protection from currents of single-phase short circuit on ground directed on maintenance to longitudinal selectivity at any kinds of short circuits; methods - analytical methods of the analysis and calculus mathematics, theory of electrical circuits, automatic control, planning and processing of results of experiment; the results - are received analytical dependences for synthesis of the circuits and device of protection from short circuits on ground, the algorithms of the analysis of an information signal and works of microprocessor devices of protection are proved; The novelty - is developed mathematical model for definition circuits SPS in a radial electrical network as functions of parameters of a zero sequence, which differs by the account of dynamic properties of a network and spectrum of frequencies of controllable sizes; had the further development a way of protection from SPS by application of correction of the dynamic distortions which have been brought in by a network and primary converters, substantiation of parameters of filters of low frequency and indemnification initial parameters of transformers of a current of a zero sequence, which provides longitudinal selectivity; the methods of formation and rating of an information signal about size of a current SPS are proved which differ by use of the simultaneous control of instant and average size of a current received as a result of multistage iteration; Degree of introduction - the results dissertations of work are used MZSHA by development of the microprocessor block circuits of protection such as UTZ-1а as a technique of processing and rating of instant values of a current; area - electric power industry