Verification of the gauss’s law with the unknown parameters by the Kolmogorov criterion in the problems of railways electric supply

Traction currents and voltages in the overhead railroad contact line hypothetically obey the Gauss’s distribution law. An algorithm for statistical modeling of the Kolmogorov distribution for the unknown values of the Gaussian law parameters has been developed. For a large number of the modeling program implementations, it has been shown that testing the hypothesis about the distribution law without taking into account the number of unknown parameters leads to an unacceptable increase in the criterion significance and a decrease in its power. The distribution of the Kolmogorov criterion is calculated with sufficient accuracy for two unknown parameters, which allows its wide practical use.

Application of PI controller based active filter for harmonic mitigation of grid-connected PV-system

The recent trends show the interconnection of PV system with electric grid. With this configuration the issue of harmonics comes into existence. The mounting figure of power-electronic instruments has formed considerable impression on the power-quality of electric supply. Harmonics deformations have conventionally been handled amid the application of passive-LC filters. Active Filter has emerged as a good substitute for passive filters to reduce the harmonics to great extent as it has numerous benefits over the former filters. The active filter’s most vital part is the applied control strategies. Several researches are being under process to advance the functioning of the filter. One of the important control requirements of filter is the regulation of DC link up capacitor voltage. Here the voltage supervision of capacitor is being done using PI controller. The paper show current harmonics compensation of PV grid connected system using PI controller based active filter. Simulation outcomes have been shown which displays the harmonics are within the IEEE boundaries.

The Economics and Regulation of Network Industries

Have you ever wondered how your telephone company or Internet service provider can give you access to almost all people in the world, or how electricity suppliers can compete with each other if there is only one electric supply line passing through your street? This Element deals with the economics and public regulation of such network industries. It puts particular emphasis on the specific economic concepts used for analyzing them and on the regulatory reform movement and the compatibility of regulation and competition. Worldwide most of these industries have changed dramatically in recent years, telecommunications in particular. Network industries mostly exhibit economies of scale in production and similar economies in consumption. Both of these properties cause market power problems that often require industry-specific regulation. However, due to technological and market changes network policies have moved on from end-user regulation to wholesale regulation and in some cases to deregulation.

Locomotive Gear Fault Diagnosis Based on Wavelet Bispectrum of Motor Current

The motor current signature analysis (MCSA) provides a nondestructive method for gear fault detection. The motor current in the faulty gear system not only involves the frequency information related to the fault but also the electric supply frequency and gear meshing-related frequency, which not only contaminates the fault characteristics but also increases the difficulty of fault extraction. To extract the fault characteristic frequency effectively, an innovative method based on the wavelet bispectrum (WB) is proposed. Bispectrum is an effective tool for identifying the fault-related quadratic phase coupling (QPC). However, it requires a large amount of data averaging, which is not suitable for short data analysis. In this paper, the wavelet bispectrum is introduced to motor current analysis and the problem of QPC extraction under variable speed conditions is preliminarily solved. Furthermore, a fault diagnostic approach for locomotive gears using the wavelet bispectrum and wavelet bispectral entropy is suggested. The presented method was effectively applied to the locomotive online running operations, and faults of the drive gear were successfully diagnosed.

EDUCATION AND TECHNOLOGY DURING COVID-19 TIMES

It is difficult to separate technology from education because technology is embedded in teaching. The best technology for teaching is the one that does not interfere with the communication between the teacher and the students. In other words, it should be barely “noticeable” in how it is used, and easy enough to use that it does not require special training, such as window in a room to see the flowers outside, without interfering in any way. The technology used during an in-person classes is so basic, transparent, and simple, since it consists of a classroom, chairs, blackboard and pieces of chalk. However, a piece of chalk could break. In this case, the flow of information is interrupted; which is why the plastic whiteboards and markers are preferable and cleaner. An electronic board may seem to be better with its many improvements with computers; however, its higher technology could get in the way if it is not used properly. During the pandemic, different technologies, like computers and cell phones, connected to internet were massively used. Yet, computers and cell phones with the appropriate software and apps had an additional cost; with no guarantee of antivirus applications against viruses or worms, leaving aside protection for documents, software and hardware. On top of that, a Zoom, Google or any similar online platform was necessary. Using these platforms, other technologies had to be relied on, including Ethernet or a USB adapter. On the other hand, in developing countries before the pandemic, low-tech was used by most students to store and pass information to their peers and teachers. They would use mainly pens and notebooks to write notes, or CD-Rs or USB to pass information. However, during the pandemic, with the advances in internet speed, many students have now moved on to using e-mail and cloud drives where they can transport their files. All the electronics listed to make online education or tech-based education needed electricity to work. In other words: no electricity, no class; no electric supply or stored electricity in batteries, no class. In this paper we analyze the role of technology in education, and how this technology could enhance or obstruct the communication between the teacher and the students.

RESEARCH AND DEVELOPMENT OF ONLINE-REALTIME SUPERVISING SYSTEM FOR LOW VOLTAGE GRIDS

This paper presents some results of fabrication and experiment of an online-realtime supervising system for low voltage grids. The experiment results show that, for the proposed system, important operating parameters of the low voltage grid such as voltage, current, power, temperatures of oil, cable are supervised and analyzed. Additionally, alarming messages are sent to operators immediately when there are abnormal phenomenon occurring at the grid. This proposed system can help improve reliability of electric supply and reduce SAIDI, SAIFI, as well as enhance safety of human being and equipment.