Centralized normalization of harmonic voltages in the supply network for traction substations

Abstract

The paper solves the problem of centralized reduction of harmonic voltages at the nodes connecting traction substations on railway to the supply HV network via the passive C-type filters. The results of measurements at the connection nodes of traction substations to the supply network of the voltage quality indices that are due to non-sinusoidality are presented. Changes of the indices at different configurations of the supply network are analyzed. Mathematical expressions to determine parameters of the C-type filters, the algorithms for selecting network nodes where they will be installed are given. The parameters of the selected nodes for 220 kV network supplying traction substations with power and also the estimates of the efficiency of work of these filters for different network configurations are presented as an example. The active power losses in the selected filters are calculated.

The problems of centralized decrease of harmonic voltages in the HV networks with distributed nonlinear loads

“…Both approaches call for huge financial expense. The possibility to apply passive filters for centralized decrease of harmonic voltages at nodes connecting traction substations to supply network is shown in [10,12]. The C-type and third-order filters were used as passive filters.…”

“…The authors of the named works suggest rather complex methods to search for the preferable nodes for filter installation. The author of this paper suggests for this purpose a simple approach called "test filter" that reflects the essence of a real tuned harmonic filter [10]. The idea of the test filter is based on the concept of passive filter at a harmonic it is tuned to.…”

“…In [6] the authors emphasize that the third-order filters are less sensitive to changes in frequency. Mathematical expressions for determining parameters of C-type filter are presented in [10] and parameters of the third-order filter -in [12]. In the paper the third-order filter will be used.…”

Centralized normalization of voltage harmonics in the network with distributed nonlinear load by the third-order filters

“…In [7] such a problem was solved for the C-type filters. The authors in [8] point out that the C-type filter is more sensitive to changes in frequency and variations in parameters of elements than the third-order filter.…”

“…The paper offers a very simple approach for present purposes that reflects the essence of a real filter at the tuned frequency. In [7] the approach is called a "test filter". The paper gives an example of choosing the third-order filter of the 5th harmonic for the 220 kV network supplying traction substations with power.…”