There are numerous publicly available articles on digital substations, including those dedicated to current and voltage measurements, time synchronization, test systems development, principles of substation design, and other aspects of this topic. But the phase shift between instantaneous signals and the corresponding values in the SV (sampled values) stream has been little discussed. We can list the following principles to reduce the phase shift between instantaneous analogue and discrete signals and the corresponding values in the SV stream. 1) Exclusion from the device, of non-essential elements that introduce additional propagation delays of analogue and discrete signals, provided that such exclusion does not adversely affect the device performance or characteristics. 2) Reduction of the delay time for the other device elements to the minimum values. 3) Adjustment of the delay time of some device elements or addition of special delay elements to equalize the time of signal propagation over analogue and discrete channels. 4) Consideration of the total delay time of signal propagation over analogue and discrete channels and adjustment of the time stamp in the SV frame. The article provides examples of application of these principles in signal generation and measuring devices and phase shift meters.

No abstract

No abstract

The results of the study on the development of corona-resistant coatings for dielectric barriers in plasma-chemical ozone generators on the base of dielectric barrier discharge are presented. The influence of the binder and filler material on the service life of the dielectric barrier is studied. The best corona resistance result was achieved using an organosilicon binder. Inorganic fillers are effective for increasing the corona resistance of the coating: Al2O3 powders, talc and others. The studies were performed in air at atmospheric pressure.

Electrical machines are widely used in various branches of the national economy. In particular, electric motors are one of the main elements in electrical power generation systems. The electric machines used at this ensure reliable operation of individual power units and the entire power supply system in general. The reliability of engines’ operation is largely determined by the quality of its insulation, that is why the improvement of methods for controlling the isolation of high voltage asynchronous motors is an actual task. The aim of the research is to develop a method of continuous automated control of electric insulation condition in stator windings of an asynchronous motor basing on the analysis of experimental and industrial operation data making it possible to estimate the dynamics of changes in the main insulation parameters. The main elements showing reliability of high-voltage electric machines, applied electro-insulation structures, methods for controlling insulation resistance in a high-voltage electric motor are considered in the article. The research performed was based on the results of the experimental and industrial operation of the automated system of insulation control under working voltage at the real facility carried out by the group of companies «Energopribor» of the town of Cheboksary. The analysis of existing methods for insulation control is given, the scheme of insulation control by superpositioning test current with the frequency which is different from industrial one. The authors propose the method to estimate the dynamics of resistance changes in insulation of stator windings of the asynchronous motor, to reveal its approximation to the maximum permissible state in the process of operation and in reserve shutdown. Software modeling was carried out, the results of which correspond to the data of experimental and industrial operation. The results obtained during the research allowed to systematize the obtained experimental data, to modernize the hardware part of the diagnostic complex DUKAT-SCAD, to outline the criteria area for its applicability.