K-26 (K-XXVI) Medium-Voltage Switchgear 6(10) kV

KRU K-26 (K-XXVI) is a line of medium-voltage cubicles for receiving and distributing three-phase power at 6/10 kV and 50/60 Hz in systems with an isolated neutral or with a neutral grounded through an arc-suppression reactor/active resistor. The series is intended for indoor switchrooms with regular switching operations using vacuum circuit-breakers.

The base design is a rigid welded steel enclosure with a powder-coat finish. The internal volume is divided by solid metallic and glass-epoxy barriers, plus automatic shutters, providing compartmentalized fault containment and safe maintenance. Lineups are assembled from standardized bays with unified primary and auxiliary modules.

Applications

K-26 is used in indoor substations and plant power systems:

System and shop substations 6-10 kV, distribution points and package substations;
Energy complexes of industrial sites, oil & gas and mining sectors;
Utilities and process infrastructure (pumping stations, data centers, water utilities, etc.);
Retrofits of existing switchgear and integration with installed feeders and cable routes.

Service conditions

Indoor installation; altitude up to 1000 m (above this - apply insulation/cooling recalculation);
Temperature range: -25...+40 °C (for sub-zero operation, heat the switchroom);
Non-hazardous area, free from conductive dust and aggressive vapors/gases; environmental conditions per EN/IEC 60721-3-3;
Service access - single- or double-sided (per substation design).

Design features

Compartmentalization: protection/LV compartment · withdrawable unit (truck) compartment · busbar compartment · cable compartment;
Shutter mechanism that automatically closes fixed contacts when the truck is moved to the test position;
Configurations: with trucks; without trucks; mixed (part of equipment fixed, part on the truck);
On the truck: vacuum CBs, VTs, station-service transformers up to 5 kVA, HRC fuses for remote SST protection;
Busbars and links in copper/aluminium; sectioning and buswork per project;
Top/bottom cable entries; interlocks and directed pressure relief are provided.

Scope of supply and variants

CB bay (with truck): enclosure, withdrawable unit, busbars, protection/LV compartment;
Bays without truck: solid busbar inlets, cable assemblies/terminations;
Mixed layout: VT on a truck, part of equipment fixed in place;
Components: circuit-breakers, disconnectors, earthing switches, post/bushing insulators - 10 kV; VTs, surge arresters, HRC fuses, station-service transformers - 6 or 10 kV (as specified).

Standards compliance

IEC 62271-1 - common specifications for MV switchgear and controlgear;
IEC 62271-200 - AC metal-enclosed switchgear up to and including 52 kV;
IEC 62271-100 - AC circuit-breakers; IEC 62271-102 - disconnectors and earthing switches; IEC 62271-103 - switches;
IEC 61869-2/-3 - instrument transformers (CTs/VTs); IEC 60529 - degrees of protection (IP code);
IEC 61000-6-2/-6-4 - EMC (industrial immunity/emissions).

Reliability and lifetime

Compartmental arc containment with directed pressure relief - adjacent bays remain serviceable;
Mechanical/electrical interlocks prevent hazardous operations; shutters can be padlocked;
Rigid metal structure minimizes vibration effects from truck movement and switching;
Corrosion resistance: galvanized steel and powder-coated facades for long-term service.

Technical data

Rated voltage, kV	6; 10
Highest system voltage, kV	7.2; 12
Rated frequency, Hz	50; 60
Rated current of main circuits, A	630; 1250; 1600; 2000; 2500; 3150
Rated busbar current, A	1250; 1600; 2500; 3150
Rated short-circuit breaking current (CB), kA	20; 25; 31.5 (per project)
Short-time withstand current (3 s), kA	20; 25; 31.5
Peak (dynamic) withstand current, kA	51; 64; 81
Power-frequency withstand (1 min), kV	28; 42 (for 7.2/12 kV classes)
Lightning impulse withstand (LI), kV	60; 75 (typical)
Busbar material/system	copper / aluminium; sectioning per project
Cable entries	top; bottom (per spec)
Cable terminations	up to 3×3-core ≤240 mm² or up to 6×1-core ≤630 mm²
Service access	single-sided; double-sided
CB endurance class	M2 / E2 / C2 (per project)
Internal arc classification (IAC)	AFL / AFLR (parameters per spec)
Environmental classification / location	EN/IEC 60721-3-3
Degree of protection (IEC 60529)	IP31 (higher ratings on request)
Overall dimensions, mm - width - depth - height	900; 1100 1660 2370

We offer documentation for manufacturing KRU K-26:

Tender package. Single-line diagrams, questionnaires, and technical descriptions for procurement and feasibility assessment.

Working drawings and 3-D models. Layout/assembly drawings, BOM, secondary schematics, cable schedules - tailored to your production.

Contract manufacturing of assemblies. We arrange fabrication of enclosures and mechanisms with certified partners; you perform assembly, installation, and factory tests.

Adaptation and integration. Equivalent/transition bays for interfacing with existing busbars/secondary circuits and third-party equipment.