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KRU 6-10 kV Kaskad series

KRU Kaskad series is designed for distribution of electric energy of three-phase AC, 50 Hz, rated voltage 6-10 kV, over the networks with isolated or grounded via the arc suppression coil or  high-ohm resistor neutral.

KRU Kaskad can be used as switchgear for power stations, transformer substations, and distribution points in various industries, namely:

- power engineering;

- oil & gas;

- metallurgy;

- mechanical engineering;

- chemicals & petrochemicals.



  • Modern design and high corrosion resistance of the structure
  • Modular design with isolated compartments for electric arc localization
  • High reliability due to high-quality materials and components
  • Wide range of power switches and relay protection terminals of domestic and foreign manufacture
  • Possible customization to fit non-standard layouts.



KRU Kaskad series consists of separate cabinets with switching devices and other HV equipment including measurement instruments, automation and safety devices, as well as control, indicator and other devices.

Depending on the rated current and voltage, the switchgear is manufactured in three sizes in width (650 mm, 800 mm, 1,000 mm). Switchgear cabinets of one size ensure complete interchangeability of withdrawable elements and spare parts.


Switchgear cabinet is a metal structure made of high-quality galvanized steel. The parts are made by cold stamping using high-precision equipment. Connections are made using reinforced steel pop-rivets and threaded joints. External elements of the structure - front doors, side panels of the end cabinets, etc. - are powder-coated.


Entire internal space of the cabinet is divided by vertical and horizontal metal partitions into isolated compartments:

- low-voltage (relay) compartment;

- withdrawable element compartment;

- busbar compartment;

- cable connection compartment.


Dimensions of the relay compartment allow the use of any microprocessor-based relay protection, control, and automation devices. To protect from harsh environment, anti-condensation heating element is installed in the compartment. Also, for convenient maintenance, there is LED lighting.


The withdrawable element compartment is a metal case with a door on the front side which is locked by multi-point lock. Bushings with fixed contacts are installed on the back panel of the compartment. Withdrawable element of the compartment is a hardware cart with a screw drive which,  depending on chamber layout, can incorporate various equipment:

- vacuum power switch;

- frame with voltage transformers;

- frame with fuses;

- current-carrying jumper.

Withdrawable elements can be in the following fixed positions: operating position; inspection position; repair (maintenance) position. On request, the withdrawable element can be equipped with motorized hardware cart, which allows to move the withdrawable element to the inspection and operating positions.

Following power vacuum switches of domestic and foreign manufacture can be used as switching devices in the chamber: VF12 (OAO "PO Eltekhnika"), ВВ/TEL - АО "GK Tavrida Elektrik, VD4 (ABB), EasyPact EXE (Schneider Electric), Susol VSB (LS Industrial Systems (LG)).

Main busbar system of the switchgear is located in the busbar compartment. Buses for currents up to 1,600 A are implemented as a single copper strip with cross-section 10 × 80 mm, for currents up to 2,500 A - two, for currents up to 3,150 A - three strips. To localize the arc within a single chamber, the buses run through bushings.

In the cable connection compartment incorporates a grounding device with a drive, current transformers, zero-sequence transformers, overvoltage limiters, insulators with capacitive voltage divider, and, on request, voltage transformers on a pull-out trolley. To access the compartment from the rear side of the chamber, there is a removable panel consisting of two parts - upper and lower. On the front side of the compartment there is arc-resistant door, which locks by multi-point lock.

Switchgear cabinets have a system of mechanical and electrical interlocks that completely complies with GOST safety requirements.






Basic technical parameters

Rated voltage (linear), kV

6; 10

Max. operating voltage (linear), kV

7.2; 12

Rated current, А:

- main circuits in switchgear chambers

 - busbars;


630; 800; 1,000; 1,250; 1,600; 2,000; 2,500; 3,150; 4,000

1,600; 2,500; 3,150; 4,000

Rated current of current transformers, A

100; 200; 300; 400; 500; 600; 750; 800; 1,000; 1,200;

1,500; 2,000; 3,000; 4,000

Built-in switch rated tripping current, кА

20; 25; 31.5

Short-time withstand current, kA

20; 25; 31.5

Withstand current time, s

 - main current-carrying circuits

 - grounding circuits




Rated peak withstand current of switchgear main circuits, kA

51; 64; 81

Auxiliary circuits rated voltage, V

 - for DC

 - for AC

 - lighting circuits


110; 220

110; 220

12; 24

Standards for testing insulation of main current-carrying circuits by one-minute 50 Hz voltage, kV

 - interphase and relative to ground

 - between the power switch terminals





Standards for testing insulation of main current-carrying circuits by lightning impulse voltage 1.2/50 ms, kV

 - interphase and relative to ground

 - between the power switch terminals





Standards for testing insulation of control and auxiliary circuits by one-minute 50 Hz voltage, kV


Min. insulation resistance, MOhm

 - main circuits

 - secondary circuits




Min. mechanical strength and durability

 - number of operations of  В - О earthing device

 - moving the withdrawable element from the inspection position to the working position and back

 - opening and closing the chamber doors

 - opening and closing the shutter mechanism

 - closing and opening of connector contact system of main circuits








Protection class as per GOST 14254


Max. chamber dimensions, mm

- height

- width

- length



650; 800; 1,000


Max. weight of the chambers with different widths, kg

- 650 mm

- 800 mm

- 1,000 mm





Insulation level

With normal insulation as per GOST 1516.1

Insulation type

Combined (air and solid)

Insulation of the main circuit busbars

With uninsulated busbars

Withdrawable  elements

With withdrawable  elements

Type of line HV bays

Cable; bus

Busbar system

With one busbar system

Phase separation method

With unseparated phases

Service type

One- and two-side service

Switchgear chamber type depending on built-in equipment and bays

- Cabinet with power switches;

- cabinet with connector type terminals;

- cabinet with surge suppressors;

- cabinet with voltage transformers;

- cabinet with current transformers;

- cabinet with cable assemblies and cable jumpers;

- cabinet wit bus terminals and bus jumpers;

- cabinet with power transformers; combined with power fuses;

- cabinet with auxiliary equipment (cabinets with auxiliary current sources and rectifying devices, relay protection, automation control boards, alarms, and communications);

- bus bridge

Doors in the withdrawable element compartment

Switchgear cabinets woth doors

Heat-insulation in switchgear cabinets

No heat-insulation

Control type

Local and remote

Climatic modification as per GOST 15150


Ambient operating temperature, °С

+40 … -25

Max. altitude above sea level, m


Service life, years


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Sale Department for the Nizhny Novgorod region: +7 (831) 275-888-9

Regional sale department (Russia and CIS countries): +7 (495) 789-49-68


7 A, ul. Elektrovoznaya, Nizhny Novgorod, Russia, 603108