The KRUN K-6 (K-VI) outdoor metal-enclosed medium-voltage switchgear is intended for the reception and distribution of three-phase AC power at 50 Hz with rated voltages of 6 and 10 kV. It is used in auxiliary switchboards of power plants, at substations of utility grids and industrial facilities, for the power supply of agricultural consumers, and in the oil & gas sector. The KRUN K-6 (K-VI) is assembled from individual cabinets with a splash-proof enclosure and two-sided service; each cabinet is divided into functional compartments to enhance reliability, personnel safety, and ease of operation.

Purpose and Applications

KRUN K-6 (K-VI) is designed for receiving and distributing three-phase power at industrial frequency 50 Hz with nominal voltages of 6 and 10 kV. The assembly is applied as 6–10 kV distribution switchgear at substations and auxiliary switchboards of power plants, at industrial and infrastructure sites, as well as for supplying critical agricultural consumers and along long transmission corridors.

Typical tasks: incoming feeders and bus sectionalizing of 6–10 kV networks; supplying outgoing feeders (cable and overhead); connection of 6/0.4 kV power transformers and station auxiliaries; measurement and revenue metering; building outdoor distribution points and package substations.

Technical Data

Operating Conditions

By environmental factors the equipment corresponds to EN/IEC 60721-3-4 (outdoor, non-weather-protected locations); enclosure protection level - IP34 (IEC 60529). For similar cabinets in the K-III series the environmental category is also specified as outdoor; the IP34 degree of protection is confirmed in the typical parameter tables.

Typical ambient temperature range for outdoor cabinets of this class corresponds to EN/IEC 60721-3-4 solutions: from -40…-45 °C up to +45 °C (cold-climate versions use anti-condensation/heating kits and the appropriate “cold” category). For the KRN-IV-10 series the lower limit is stated as -45 °C, and for open-air installation -40…+45 °C.

By mechanical environmental factors the assembly corresponds to class 4M4 per EN/IEC 60721-3-4; insulation and dielectric requirements follow IEC 62271-1 / IEC 60071-1. The enclosure degree of protection is defined by IEC 60529.

For installation above 1000 m a.s.l., apply altitude correction factors to insulation withstand levels as commonly required for medium-voltage switchgear (IEC 62271-1 guidance).

Layout and Construction

Each KRUN K-6 (K-VI) cubicle is made in a splash-proof metal enclosure and divided into independent compartments: disconnector & busbar compartment; medium-voltage circuit-breaker (VCB) compartment; incoming/outgoing feeder compartment; relay compartment; control compartment. This zoning confines any fault to a single compartment and ensures safe servicing.

The disconnector & busbar compartment houses oil/air bushing insulators, the disconnector, and busbars; a removable mesh viewing screen behind the door enables visual position check of the blades with doors closed. The MV circuit-breaker compartment accommodates a vacuum circuit-breaker and a space heater; with cable entry, zero-sequence current transformers (CBCT) can be installed.

The control compartment includes operating mechanisms for the busbar and line disconnectors (PR-10), and lighting; the relay compartment holds protection, automation, signaling and measuring devices, as well as mechanical interlock mechanisms. Access to all compartments is via doors with multi-point latches and provisions for padlocking.

The RVZ disconnector is operated by two PR-10 mechanisms: one linked by tie-rod to the main blade shaft, the other to the earthing blade shaft; a mechanical interlock between shafts prevents closing of the earthing blades when the main blades are closed. The VCB is operated by push-buttons and/or a manual mechanism (for certain VCB types).

Terminations: bottom cable entry and/or side/rear bus connections via busducts/adaptors; front panels can provide voltage presence indicators and test sockets for phasing checks.

Cabinet earthing is performed by welding the base frame to the site grounding grid; metallic parts of built-in devices are bonded to the enclosure via earthing bars/star washers/sliding contacts.

Safety and Interlocking

The assembly includes a system of mechanical and electromechanical interlocks preventing incorrect operations and ensuring safe access to compartments. Operation with faulty interlocks is prohibited; before work, absence of voltage must be verified and portable earthing applied - in accordance with applicable safety rules and local procedures.

Key interlocks: blocking of earthing-blade closing when main blades are closed; access blocking to compartments for incorrect disconnector/earthing positions; door latching with rod mechanisms; cross-interlock between operating shafts; blocking of any movement of withdrawable parts (if present) without connected secondary circuits; optional key and electronic interlocks for busbar earthing switches.

Typical safe-access sequence: open the VCB; open the disconnector; close the earthing blades; open the relevant compartment door; verify absence of voltage; remove the mesh guard if required.

For additional protection, arc-flash detection systems (optical/pressure) with pressure-relief flaps can be used to reduce arc energy and localize damage.

Variants and Options

KRUN K-6 (K-VI) cabinets are configured to project needs. The composition may include vacuum circuit-breakers from various manufacturers and the following options:

• Vacuum circuit-breakers: ABB VD4, Schneider Electric Evolis, Alstom/GE HVX/ECA; rated currents 630…3150 A (depending on series).
• Current transformers for protection, measurement and metering; zero-sequence CTs (CBCT).
• Voltage transformers (single-phase UGE/Y12G or equivalents); HV fuses; busbar earthing switches.
• Surge arresters on incomers/busbars.
• Protection & control: electromechanical relays and digital IEDs (Sepam, MiCOM, SPAC, Orion, etc.); metering - any modern meter types.
• Voltage presence indicators and test/phasing sockets.

Typical Configurations

KRUN K-6 (K-VI) is assembled from individual panels (incoming, bus sectionalizer, feeder, VT, station-service, etc.). VCB panels include line and bus disconnectors, the VCB, current transformers; surge arresters and zero-sequence CTs are available per specification. The VT panel contains a voltage transformer with a bus disconnector and fuses, plus busbar earthing blades; the station-service (SS) panel contains a 25/40 kVA transformer with protective device.

• VCB panel - vacuum circuit-breaker panel (cable/bus/overhead entry).
• Bus sectionalizer - CB/disconnector for bus sectionalizing and redundancy.
• VT panel - voltage-transformer panel (with fuses and bus disconnector).
• SS panel - station-service transformer 25/40 kVA with protective device.

Standards Compliance

• EN/IEC 60721-3-4 - environmental classification (outdoor, non-weather-protected).
• IEC 60529 - degrees of protection of enclosures (IP code; for KRUN K-6 - IP34).
• IEC 62271-200 - AC metal-enclosed switchgear and controlgear, 1–52 kV.
• IEC 62271-1 / IEC 60071-1 - insulation requirements and insulation co-ordination.
• IEC 61936-1 - power installations exceeding 1 kV AC (design & erection).

Working with Contractors and Partners

We welcome cooperation with manufacturing sites, investors and EPC contractors. On request we will configure the optimal KRUN K-6 (K-VI) architecture for your project - from auxiliary switchgear of TPPs/HPPs to distribution points along overhead lines and oil & gas fields. Adaptation to breakers and protection devices available in your market is provided, as well as localization of metalwork and assembly, and support during type/acceptance tests and commissioning.

If needed, we can organize manufacturing of individual assemblies on a cooperative basis (enclosures, busducts, VT/SS panels, cable entries), supply of spares, and training of production staff. For sites with special conditions - selection of anti-corrosion coatings, heating/ventilation kits, air filtration, and snow-retention for service platforms.

Documentation Delivered

Each KRUN K-6 set is supplied with a complete package of factory and working documentation sufficient for manufacturing, installation and operation:

• Product data sheet; Operation manual/Technical description; primary and secondary schematics; connection diagrams; operating documents for components.
• Full set of fabrication drawings for the cabinet metalwork, assemblies and parts; bills of materials and purchased components; paint maps and coating requirements.
• 3D models and exchange files for your CAD: DWG/DXF (AutoCAD), SLDPRT/SLDASM (SolidWorks), STEP/Parasolid; installation sketches, external wiring diagrams, cable and terminal lists.
• Factory test programs and procedures, test reports, protection settings lists, and templates for operational interlock cards.

Why Work with Us

- No need to maintain a large team of highly qualified design engineers - you receive a documentation set that can be executed by an engineer of average qualification.
- No need to build prototypes - our experience allows immediate launch of serial production.
- Working to our documentation - your specialists receive support on all nuances of manufacturing KRUN K-6.

For additional information on KRUN K-6 please contact: inbox@proekt-energo.com

…and as is well known - an error made at the design stage leads to ten-fold costs in manufacturing, and a hundred-fold in operation…

PDF - Download KRUN K-6 Technical Information.