Menu English Ukrainian russian Home

Free technical library for hobbyists and professionals Free technical library


ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Encyclopedia of radio electronics and electrical engineering / Electrician

Section 1 General Rules

Measurements of electrical quantities. Frequency measurement

Free technical library

Encyclopedia of radio electronics and electrical engineering / Rules for the installation of electrical installations (PUE)

Comments on the article Comments on the article

1.6.16. The frequency measurement must be made:

1) on each section of the generator voltage tires;

2) on each generator of a block thermal or nuclear power plant;

3) on each system (section) of high voltage busbars of the power plant;

4) at the nodes of the possible division of the power system into non-synchronously operating parts.

1.6.17. Registration of the frequency or its deviation from the set value should be carried out:

1) at power plants with a capacity of 200 MW or more;

2) at power plants with a capacity of 6 MW or more, operating in isolation.

1.6.18. The absolute error of registering frequency meters at power plants involved in power regulation should not exceed ± 0,1 Hz.

See other articles Section Rules for the installation of electrical installations (PUE).

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

A New Way to Control and Manipulate Optical Signals 05.05.2024

The modern world of science and technology is developing rapidly, and every day new methods and technologies appear that open up new prospects for us in various fields. One such innovation is the development by German scientists of a new way to control optical signals, which could lead to significant progress in the field of photonics. Recent research has allowed German scientists to create a tunable waveplate inside a fused silica waveguide. This method, based on the use of a liquid crystal layer, allows one to effectively change the polarization of light passing through a waveguide. This technological breakthrough opens up new prospects for the development of compact and efficient photonic devices capable of processing large volumes of data. The electro-optical control of polarization provided by the new method could provide the basis for a new class of integrated photonic devices. This opens up great opportunities for ... >>

Primium Seneca keyboard 05.05.2024

Keyboards are an integral part of our daily computer work. However, one of the main problems that users face is noise, especially in the case of premium models. But with the new Seneca keyboard from Norbauer & Co, that may change. Seneca is not just a keyboard, it is the result of five years of development work to create the ideal device. Every aspect of this keyboard, from acoustic properties to mechanical characteristics, has been carefully considered and balanced. One of the key features of Seneca is its silent stabilizers, which solve the noise problem common to many keyboards. In addition, the keyboard supports various key widths, making it convenient for any user. Although Seneca is not yet available for purchase, it is scheduled for release in late summer. Norbauer & Co's Seneca represents new standards in keyboard design. Her ... >>

The world's tallest astronomical observatory opened 04.05.2024

Exploring space and its mysteries is a task that attracts the attention of astronomers from all over the world. In the fresh air of the high mountains, far from city light pollution, the stars and planets reveal their secrets with greater clarity. A new page is opening in the history of astronomy with the opening of the world's highest astronomical observatory - the Atacama Observatory of the University of Tokyo. The Atacama Observatory, located at an altitude of 5640 meters above sea level, opens up new opportunities for astronomers in the study of space. This site has become the highest location for a ground-based telescope, providing researchers with a unique tool for studying infrared waves in the Universe. Although the high altitude location provides clearer skies and less interference from the atmosphere, building an observatory on a high mountain poses enormous difficulties and challenges. However, despite the difficulties, the new observatory opens up broad research prospects for astronomers. ... >>

Random news from the Archive

Earth's lakes are evaporating faster than thought 06.07.2022

Scientists from the University of Texas said that the Earth's lakes are evaporating much faster than thought. And this evaporation plays a much larger role in the hydrological cycle than expected and has a significant impact on climate and weather modeling.

Natural and artificial lakes occupy approximately five million square kilometers of the Earth's area. They contain about 90% of fresh water and are home to an amazing variety of organisms.

But the increase in temperature and solar radiation associated with changes in cloud cover adversely affects the lakes. Decreasing ice cover also means that large areas of water are exposed to sunlight. All this together leads to an acceleration of the water cycle, from accumulation on land to dispersion in the atmosphere.

Previous estimates of this process have been based on evaporation rates, but these estimates alone are not sufficient to reflect the net amount of lake water lost due to other factors such as freeze and thaw cycles. Because of this dependence on local environmental conditions, a reliable evaporation rate must be calculated separately for each lake.

This is exactly what the authors of the new study did for 1,42 million lakes around the world. They used monthly satellite water loss information between 1985 and 2018 and took into account evaporation rates, surface area, ice duration, and heat storage changes for each of these lakes.

"We found that the long-term evaporation from the lake is 1500 plus or minus 150 cubic kilometers per year, which is 15,4% more than previous estimates," said Gang Zhao, lead author of the study.

That is, the sky "absorbs" three trillion liters of water more than previously thought. It also turned out that artificial reservoirs make a disproportionately larger contribution to evaporation: 16% with a capacity of 5%.

From a global perspective, lake evaporation may be higher than domestic and industrial water sharing. However, reliable data on evaporation exist for only a small number of lakes.

Other interesting news:

▪ The benefits and harms of video games

▪ World's largest magnet under construction

▪ Dubike smart bike from Baidu

▪ triangular snowflakes

▪ Artificial mother of pearl

News feed of science and technology, new electronics

 

Interesting materials of the Free Technical Library:

▪ section of the website job descriptions. Article selection

▪ article to the Modeller about the helicopter. Tips for a modeller

▪ article What is a cloud? Detailed answer

▪ ricin article. Legends, cultivation, methods of application

▪ article Vortex tubes. Encyclopedia of radio electronics and electrical engineering

▪ article Color prediction maps. Focus Secret

Leave your comment on this article:

Name:


Email (optional):


A comment:





All languages ​​of this page

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua

www.diagram.com.ua
2000-2024