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The widespread use of Voltage Source Converter based High Voltage Direct Current Transmission (VSC-HVDC) technology has significantly increased the complexity of grid configuration and operation, which demands higher quality of AC/DC state estimation. The bad data detection and identification plays a vital role in ensuring the accuracy of state estimation outcomes. This paper presents a new approach to bad data in hybrid AC/DC grids based on the combined deep belief network (DBN) and K-means clustering method. First, the DBNs are trained separately for active and reactive power given the characteristics of VSC-HVDC by which the bad data can be detected. Then, an improved K-means is used for clustering the DBN outputs by setting the mean and the number of the samples within the clusters as two metrics for bad data identification. Finally, the case study is performed in a modified IEEE 14-bus system and the results demonstrate the effectiveness of the proposed method in terms of both the accuracy and efficiency. DOI: 10.5755/j01.eie.25.2.23206

The paper deals with Power System State Estimation (PSSE) that plays essential role in modern dispatcher centres. The aim of the paper is to present results of original investigations on change of properties of PSSE when a symmetrical phase shifter is installed in a Power System (PS). The mentioned phase shifter is one of the types of phase shifters. Such the phase shifter is installed in the Polish Power System. In the paper, the following indices characterizing properties of PSSE are considered: the number of iterations in PSSE calculation, the conditionality of the solved equations and accuracy of estimation. The investigations are made using the IEEE 14-bus test system. The properties of PSSE are analysed when there is the phase shifter and when there is not such the device in PS for the polar and rectangular coordinate systems. The investigations are so organized to take into account possibly all space of states of PS. Results of the investigations show that there is noticeable change of the properties of PSSE as an effect of installation of the phase shifter in PS. In the paper, also such the cases are indicated, in which those changes are the smallest. DOI: http://dx.doi.org/10.5755/j01.eie.24.4.21473