Complete switchgear (KRU): types, characteristics, purpose

This article will contain information about the complete switchgear. Their technical characteristics, types and purpose will be given.

Scope of application

Complete switchgear (KRU) - a device consisting of shields, which are built into:

• Devices for starting and controlling electric receivers;
• Protection devices;
• Current-measuring devices;

And also other additional components, assembled and ready to work.

The main purpose is to receive and further distribute electricity in three-phase networks with an operating frequency of 50 Hz and a voltage of more than 1000 V.

Complete switchgear (KRU) is divided into two types: outdoor and indoor installation. For indoor installation place in buildings or in premises. Such devices are assembled with a busbar system. When used for operating voltage over 35 kV, air insulation is used, in networks of 110 kV the insulation is SF6 gas.

As a rule, modern switchgears use high-voltage vacuum switches as a protection and switching device, but there are more obsolete installations in which oil switches are installed .

Distribution cabinets КРУ РН 6 are made for outdoor installation and are divided into two types of execution: rolling out, in which all parts and components are fixed on a special board, and stationary, where all parts and components are installed for a long service life.

Installation of an external installation

Complete outdoor switchgear must be prepared for installation, so first of all lay the foundation. Cells are moved in a packed form before installing all devices. After this, the carts are unpacked and rolled out of the housing, in which the switching equipment is installed. Set the cells according to the layout plan. Installation begins with an extreme. After making sure of the correct installation of the cabinet, install the following. It is important that the cells do not have to stand at an angle.

And for the installation of overhead lines on the roof mount brackets. It is also necessary to install local lighting near each cell. High-voltage cable lines with the help of end clutches are fixed to the KRU terminals in the back door of the cabinet. After that, the complete outdoor switchgear is ready for operation.

Design performance

The complete switchgears (switchgears) for 6/10 kV voltage are calculated, and all elements installed in it must function properly. KRU are outwardly similar to large steel cells, inside of which are mounted switching, protective and auxiliary devices. The outer coating of the cell is made of steel sheets, this is done to increase the strength of the structure and protect it from short-circuit current damage of other devices located side by side.

Distribution cabinets КРУ РН 6 are equipped with special local heating, thanks to which the current-measuring devices function normally in the winter.

Technical characteristics and switching capacity

The complete switchgear (KRU) 10 kV has the following nominal data:

• Operating voltage of the network - 6, 10, 35, 110 kV;
• The industrial operating frequency of the network is 50 Hz;
• Operating current - 630 A;
• The breaking current is 12.5, 20, 25, 35, 40 kA;
• Insulation - air;
• Type of switches - vacuum;
• Type of transformer current - ТОЛК-6;
• Type of power transformer - TM-25;
• Drive type - electric.

Switching stability of switchgear is determined based on the parameters of the equipment, which is built into the device of switches with the drive installed on it. The switching equipment, which is installed on the switchgear, must operate normally at rated loads and withstand test cycles at high values of the tripping currents that are set in the technical characteristics of the internal apparatuses.

Retractable element and degree of protection

The withdrawable element on which switching equipment is installed can be transmitted either manually or mechanically. At the same time, such a trolley must pass the path along smooth surfaces, since it has a rather large mass.

All cabinets KRU should be convenient for operation and are designed for comfortable installation, repair and replacement of parts. In most switchgear cabinets during the rolling out of the sliding carriage from the cell to the working position, the openings to the fixed disconnect contacts of the main circuit are locked with special curtains.

Depending on the type of application, the installation is of different types of performance. KRU must comply with the requirements of the eclectic and mechanical strength of the structure, insulation and resistance to aggressive operating conditions. Categories of placement of switchgear:

• U3 - designed to work in rooms with natural air circulation;
• U4 - are intended for premises with artificial climatic conditions.

The design of the switchgear must provide stability in the case of vibrations that occur during the switching on and off of high-voltage switches, and also when the installation is moved. At the same time, all devices must work properly, and relay protection does not work during operation at rated values.

KRU can be made for different climatic conditions with the use of local heating or cooling.

Exploitation

When using the switchgear it is necessary to timely arrange for technical inspection and maintenance of the equipment that is located in the cell, as well as troubleshoot.

Observation of the operation of the equipment is done by electricians on duty or personnel who operate the unit. According to modern safety requirements, one person is not allowed to work with electrical installations, therefore at least two are necessary when working with switchgear.

Workers who repair the plant must be trained and have a tolerance group of not less than IV, and must also be aware of the equipment in the switchgear and represent the work of individual parts of the electromechanisms.

Installation with operating voltage up to 35 kV

The BM-4 series high-voltage switchgear is used for power transmission in three-phase current networks with an industrial frequency of 50 Hz and an operating voltage of 35 kV.

The KRU cell is a structure lined with galvanized steel, the sheets of which are connected by a welded or riveted method. Inside, high-voltage switches, voltage transformers, switching equipment, measuring devices and a disconnector are installed.

Such switchgear is designed for two-way maintenance. When installed in small-sized structures, they produce a modified switchgear with one-sided maintenance. To maintain the temperature in the cells there are blinds. Also, to dispose of excess pressure, which may appear in the event of emergency operation or short-circuit currents, rupturable valves are installed on the cell roof.

The device of mark K-63

Switchgear K-63 is made of a metal body rigidly fixed on supports, inside of which is all the protective, switching and transformer equipment. Complete switchgear type KRU K-63 as well as the rest are designed for transmission and distribution of electric current in three-phase networks, with an industrial frequency of 50 Hz and with an operating voltage of 6 kV.

A feature of K-63 switchgear is that it can be used as a transformer device. The main switching devices K-63 are modern high-voltage switches BB / TEL with the use of electromechanical relays or microprocessor protectors.

Cells K-63 are designed for indoor installation, and the transformer can be outdoors. K-63 is assembled with a single system of busbars, electricity is fed through high-voltage cells in the switchgear, which are located on the roof.

The device of mark K-594: advantages

Complete switchgear KRU K-594, as well as all of the above facilities, are used in networks with a voltage of 6-10 kV and an operating frequency of 50 Hz.

As a rule, switchgears K-594 are used in transformer substations, power stations, agricultural facilities and railway transport. The switchgear KRU-594, whose price depends on the supplier and the region of purchase, is excellent for connecting high-voltage motors and other electrical machines. The main advantages of the switchgear are:

• All electromechanisms are assembled in one cell and are completed at the factory;
• The switchgear improves the safety of the installation itself, as well as of the working personnel;
• All the most complex elements are installed on a rolling cart, which reduces the complexity of the maintenance of equipment;
• The cells of the switchgear are not bulky, so they significantly save space in the room.

The K-594 series switchgears have technical characteristics that can be changed in case of an increase or decrease in the rated ratings of consumers to which the switchgear will be connected.

Conclusion

Switchgear is a reliable way to connect consumers, as it has high reliability and ease of use, as well as ease of maintenance and repair. They have earned their popularity in the world market as reliable equipment for electricity transmission.