Monthly Archives: January 2023

Application of Electrical Substation, Ring Topology versus Star Topology

17 January 2023Fără categoriecburada

Abstract

In order to solve the problem of analyzing network performance of SCADA (Supervisory Control And Data Acquisition) system communication of power grid in effective and practical way, this paper proposes to change the star topology with ring topology, specifically method rapid spanning tree protocol (RSTP), in an electrical substation. The paper discusses about SCADA architecture, main equipment like remote terminal unit, intelligent electronic device, server, server network time protocol, HMI (human machine interface), router and their role in the electrical substation. Also, the levels of the command hierarchy in the SCADA system are discussed. Each level has certain tasks set for the optimization and reliability of the electrical substation. The data flow describes the types of information that are transmitted between hierarchical levels. In the last part the paper the topologies of the system are described.

Analyzing the Influence of Harmonic Parameters on Accuracy Indices When Applying Wavelet Transform

17 January 2023Fără categoriecburada

Abstract

The paper deals with the evaluation of root mean square deviations and maximum absolute relative errors associated to the decomposition followed by recomposition based on Wavelet Packet Transform (WPT) of signals polluted with harmonics. Subtrees associated to sets of harmonics presenting practical interest for industrial applications are addressed. The study uses artificial signals generated through the superposition of perfect sinusoids with pairs of harmonics which proved to be related in an almost exclusive manner to pairs of nodes from the bottom level of a WPT tree. 4 parameters had to be considered when determining the maximum and minimum values of errors for each set: the clustered harmonics’ magnitudes and their phase-shifts relative to the  omponent of fundamental frequency. The decomposition/recomposition are time-efficient due to an original system of flags labeling each node from the WPT tree. For each analyzed set of harmonics, 3d graphical representation of minimum and maximum errors along with the associated 3d graphical representation of the phaseshifts are provided. At the same time, per set limits of errors ranges were established and discussed while specific patterns were deduced for the context in which extreme errors appear (phase-shifts and harmonic magnitudes). The results were commented, and conclusions were drawn.