Section 1 General Rules

Norms of acceptance tests. Bushings and bushings

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

Comments on the article

1.8.34. 1. Measurement of insulation resistance.

Produced with a megohmmeter for a voltage of 2,5 kV at bushings with paper-oil insulation. The insulation resistance of the measuring and last plates of the inputs relative to the connecting sleeve is measured. The insulation resistance must be at least 1000 MOhm.

2. Measurement of tg δ and insulation capacitance.

tg δ and insulation capacitance are measured:

• basic insulation of inputs at a voltage of 10 kV;
• insulation of the measuring capacitor PIN (C2) and/or the last layers of insulation (C3) at a voltage of 5 kV.

The limit values ​​of tg δ are given in Table. 1.8.30.

The maximum increase in the capacity of the main insulation is 5% relative to that measured at the manufacturer.

The tg δ values ​​are normalized, normalized to a temperature of 20 ºС. The reduction is carried out in accordance with the input operating instructions.

3. Power frequency high voltage test.

The test is mandatory for bushings and bushings for voltages up to 35 kV.

The test voltage for bushings and bushings, tested separately or after installation in a switchgear, is taken according to table. 1.8.31.

Testing of bushings installed on power transformers should be carried out in conjunction with testing of windings according to the standards adopted for power transformers (see Table 1.8.12).

The duration of application of the normalized test voltage for bushings and bushings is 1 min.

The bushing is considered to have passed the test if no breakdown, flashover, sliding discharges and partial discharges in oil (for oil-filled bushings), gas emissions were observed, and also if after the test no local overheating of the insulation was detected.

4. Checking the quality of the seals of the inputs.

Produced for non-hermetic oil-filled bushings with voltages of 110 kV and higher with paper-oil insulation by creating an excess oil pressure of 0,1 MPa in them. Test duration 30 min. During testing there should be no signs of oil leakage. The permissible pressure drop during testing is no more than 5%.

5. Testing transformer oil from oil-filled bushings.

The filled oil is tested according to the indicators of paragraphs 1-6 of the table. 1.8.33.

Sealed bushings are not tested for oil.

Table 1.8.30. Limit values ​​tg δ

Table 1.8.31. Industrial frequency test voltage of bushings and bushings

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 Flexible thin batteries based on nickel fluoride 07.05.2014 James Tour (James Tour) and his fellow scientists at Rice University Laboratory have developed a flexible and ultra-thin battery, consisting of nanoporous nickel-fluoride electrodes, which "envelop" the electrolyte in layers. The model of the electrochemical capacitor presented by them has a thickness of only 0,025 cm, but in the future it can be easily scaled depending on the purpose of use. This will require either adding new layers or increasing their current sizes. During testing by students at Rice University, the operation of a flexible plate battery was tested in practice. The device, small in size, successfully coped with a cycle of 10 charges and discharges, eventually losing 24% of its declared capacity before testing. The battery has also been tested for 1000 flex cycles. Of course, there have been attempts to develop such thin rechargeable batteries before, but their capacity at the time of their appearance left much to be desired, demonstrating significantly worse results compared to classic lithium-ion batteries. “The materials previously used to create high-capacity batteries were very brittle in nature, so it was really difficult for us, as specialists, to find the right combination of elements to create a flexible battery with characteristics that meet all modern standards. The Laboratory had flexible systems at its disposal. However, we chose nickel fluoride as a more promising material with great potential. The system itself is both a battery familiar to users of mobile devices and at the same time a supercapacitor. All this makes it possible to charge and discharge a flexible thin-film battery based on nickel fluoride at a sufficiently high speed and at a high current, spending the shortest possible time on this. But if you need to use the battery as a standard battery for mobile electronics, then the system is able to charge and discharge much more slowly,” one of the project participants said in an interview. To create the supercapacitor, the scientists deposited a 900-nm layer of nickel fluoride on a special substrate with special 5-nm pore-holes. After that, the substrate was removed, and the electrolyte used in the structure in the form of a solution of potassium hydroxide in polyvinyl alcohol was "squeezed" into a single structure by electrode plates on both sides. As a result, specialists from the Laboratory managed to avoid the appearance of potential signs of deformation of the created flexible structure, and students in practice confirmed the assumption of the reliability of the development after the completed testing stage. Everything described above is an extremely reliable, capacious system, which in turn is as simple as possible to create very powerful battery systems. Some companies have already expressed interest in further commercializing the project, which could prioritize the use of such nanobatteries in portable electronics and increasingly popular wearable gadgets such as smartwatches and medical bracelets.

Other interesting news:

▪ Powerful 40V N-Channel MOSFETs

▪ Biodiesel from chicken bones

▪ solar inflatable oven

▪ Space fragrance from NASA

▪ Fast computer mouse Logitech G402 Hyperion Fury

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Spy stuff. Article selection

▪ article Alteration of the washing machine for low water pressure. Tips for the home master

▪ article Which capital city has the longest name? Detailed answer

▪ article Labor Economist. Job description

▪ article Electronic cube. Encyclopedia of radio electronics and electrical engineering

▪ article Disappearance of a coin from a hand. Focus secret

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

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

www.diagram.com.ua
2000-2024