Norms of acceptance tests. Complete switchgears for indoor and outdoor installation (KRU and KRUN)

Free technical library

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

Section 1 General Rules

Norms of acceptance tests. Complete switchgears for indoor and outdoor installation (KRU and KRUN)

Free technical library

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

Comments on the article

1.8.25. The test standards for switchgear elements: oil circuit breakers, instrument transformers, load switches, valve arresters, fuses, disconnectors, power transformers and transformer oil are given in the relevant paragraphs of this chapter.

1. Insulation resistance measurement:

a) primary circuits. Produced with a megohmmeter for a voltage of 2,5 kV.

The insulation resistance of the fully assembled primary circuits of the switchgear with the equipment and nodes installed in them must be at least 100 MΩ.

In case of unsatisfactory test results, the resistance is measured element by element, while the insulation resistance of each element must be at least 1000 MΩ; testing of complete switchgears filled with SFXNUMX at the factory and not subject to opening during the entire service life is not carried out;

b) secondary circuits. Produced with a megohmmeter for a voltage of 500-1000 V.

The insulation resistance of each secondary circuit connection with all connected devices (relays, devices, secondary windings of current and voltage transformers, etc.) must be at least 0,5 MΩ.

2. Power frequency overvoltage test:

a) isolation of primary circuits of KRU and KRUN cells. The test voltage of fully assembled KRU and KRUN cells with trolleys pumped into the working position and closed doors is indicated in Table 1.8.22.

The duration of application of the normalized test voltage is 1 min;

b) isolation of secondary circuits. Produced with a voltage of 1 kV. The duration of application of the normalized test voltage is 1 min.

3. DC resistance measurement.

The resistance of detachable and bolted connections to direct current should not exceed the values given in Table 1.8.23.

4. Mechanical tests.

Produced in accordance with the manufacturer's instructions. Mechanical tests include:

a) racking in and out of retractable elements with checking the mutual engagement of the disconnecting contacts, as well as the operation of shutters, interlocks, latches, etc.;

b) checking the operation and condition of the contacts of the grounding switch.

Table 1.8.22. Test voltage of industrial frequency of isolation of KRU and KRUN cells

Voltage class, kV	Test voltage, kV, cells with insulation
Voltage class, kV	ceramic	from solid organic materials
to 0,69	1	1
3	24	21,6
6	32	28,8
10	42	37,8
15	55	49,5
20	65	58,5
35	95	85,5

Table 1.8.23. Permissible values of DC resistance of KRU elements

Measured element^*	Permissible resistance values
1. Primary plug-in contacts	Permissible contact resistance values are given in the factory instructions. In cases where the contact resistance values are not given in the factory instructions, they should be no more than:
	for 400 A contacts - 75 µOhm;
	for 630 A contacts - 60 µOhm;
	for 1000 A contacts - 50 µOhm;
	for 1600 A contacts - 40 µOhm;
	for contacts for 2000 A and above - 33 μOhm;
2. Connection of the grounding of the withdrawable element with the housing	No more than 0,1 ohm

* The measurement is carried out if the design of the switchgear allows.

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

DEll Wasabi PZ310 Mobile Printer 25.03.2009

Dell, which plans to enter the smartphone market soon, announced the release of the Wasabi PZ310 mobile printer for instant digital photo printing.

The novelty has dimensions of 122,5x75x24,2 mm with a weight of 225 g and contains a 450 mAh battery. The device is equipped with USB and Bluetooth 2.0 interfaces and is capable of printing 50x76,2 mm color images in 1 minute. The Dell Wasabi PZ310 printer will go on sale for $149.

Other interesting news:

▪ Energy saving according to the flamingo way

▪ World's largest clean energy corridor built

▪ Thimble game with wolves

▪ Mean Well Fanless Digital Power Supply PHP-3500

▪ HP Omen Mindframe Headset with Cooling Ears

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the website job descriptions. Article selection

▪ article If I get sick, I won't go to the doctors. Popular expression

▪ article Who Invented the Spotting Scope? Detailed answer

▪ article Audio. Repair Secrets

▪ article Fire and security alarm systems (OPS). Encyclopedia of radio electronics and electrical engineering

▪ article Drilling machine. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

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