KRUN-10 (KRPZ-10) Outdoor Medium-Voltage Metal-Enclosed Switchgear

Purpose and application

KRUN-10 is intended for receiving, sectionalizing, and distributing three-phase 50 Hz AC power at 6–10 kV for power and industrial facilities. It is effectively used in station service switchgear of power plants, supply centers and node substations of utility grids, at industrial plants (metallurgy, chemical, mining), in the oil & gas sector, at traction substations, and at distribution points for agricultural facilities. The solution is engineered for outdoor service and offers high readiness for use as part of skid/block-type substations and distribution points, as well as standalone incoming/distribution points.

KRUN-10 is modular: the type and quantity of cubicles are selected per project. The typical lineup includes incomer cubicles (cable and overhead), feeder cubicles, busbar sectionalizing cubicles with a circuit breaker or a disconnector, voltage-transformer (VT) cubicles, and station service transformer (SST) cubicles. This arrangement enables versatile 6–10 kV supply schemes to feed 6/0.4 and 10/0.4 kV transformers, motor loads, electric furnaces, pumping stations, compressor stations, etc., with options for remote monitoring and control.

Design accounts for required supply modes: normal, post-fault, and maintenance. KRUN-10 supports schemes with busbar sectionalizing, redundant incomers, automatic transfer (ATS), and selective protection settings. Thanks to its modularity, the switchgear is equally convenient for new substations and for refurbishment of existing 6–10 kV switchgear without prolonged production downtime.

Technical data

Service conditions

The equipment is intended for outdoor installation and complies with EN/IEC 60721-3-4 (stationary use at non-weatherprotected locations). The enclosure provides up to IP34, ensuring protection against precipitation/spraying water and ingress of typical outdoor dust. Standard execution is designed for continuous duty at installation altitudes up to 1000 m above sea level and seismic resistance up to intensity 9 (to be confirmed in the project on request). Operating position - vertical.

For cold climates, anti-condensation measures and heating are provided (heaters in the breaker, relay, and drive compartments; thermostatic temperature control) to increase switching reliability at sub-zero temperatures. For dusty/aggressive environments, optional features are available: anti-corrosion coatings, enhanced paint durability, reinforced seals and louvers, dust filters/brush seals, drip guards, as well as reinforced mechanical design for areas with elevated wind and icing loads.

From the standpoint of mechanical stresses, KRUN-10 is structurally designed to withstand transport and in-service accelerations, vibration, and shock loads typical for installation on foundations or skids. Storage and transportation are permitted in factory packaging; when supplied assembled, outdoor storage is allowed with the cubicles kept vertical and protected from weather until installation.

Layout and design solutions

Each KRUN-10 cubicle is a welded steel structure made of bent sheets with rigidly fixed panels and full partitions between compartments. A typical cubicle includes: a medium-voltage circuit-breaker compartment, a disconnector/busbar compartment, an incoming termination compartment (for cable or overhead connection), a relay compartment, and a control/drive compartment. Compartments are separated by metal partitions; access is protected by doors with multi-point latches. Behind the busbar-compartment door a removable protective screen (mesh/insulating) is installed to visually check disconnector blade position without access to live parts.

An incoming/feeder cubicle with a vacuum circuit breaker contains: line and busbar disconnectors (with earthing blades), a vacuum breaker, phase and zero-sequence current transformers (for cable entry), surge arresters, and busbars. The VT cubicle contains voltage transformers with fuses and a busbar disconnector; earthing blades for the bus are provided, with the option to install surge arresters on the busbars. The SST cubicle houses a 6(10)/0.4 kV station service transformer (typical ratings 25 or 40 kVA; other ratings per data sheet), with appropriate protection and switching. The relay compartment is equipped with a removable panel with microprocessor protection relays (IEDs), measuring instruments, alarms, and SCADA/automation elements.

Modern 6–10 kV vacuum circuit breakers with high mechanical and interrupting life are used as switching devices. Disconnector drives are manual (PR-10 type) or motorized per project; independent drives with mechanical interlocking are implemented for earthing blades. The cubicle earthing system connects the enclosure to the station earth grid; all metallic parts and built-in device enclosures are bonded to the frame using copper straps and serrated washers. For mobile configurations, cubicles can be supplied on skids; for stationary installations - mounted on a foundation/channels. Ventilation is natural via louvers/filters; local heating/dehumidification can be provided in certain versions.

Busbars are aluminum or copper, sized for the rated current (630–1600 A typical for KRUN-10). Electro-dynamic and thermal withstand of current-carrying parts is ensured by the design of bus bridges, insulation clearances, and use of support/feed-through insulators corresponding to the specified short-circuit levels. Line entries are either cable (via glands/terminations) or overhead (via bushings and a roof traverse). Field installation provides convenient access to lugs, terminals, and connection points of cables/overhead lines without disassembly of main assemblies.

Safety and interlocking

Safe maintenance is ensured by a combination of design measures and interlocks. Access to de-energized compartments is permitted only following the required sequence: open the breaker, open disconnectors, close earthing blades, verify absence of voltage, and apply portable earthing. Mechanical interlocks prevent human error: impossible to close an earthing device with main blades closed; impossible to operate the disconnector with the breaker closed; access is blocked when a disconnector is in an energized position. Additional electrical interlocks are provided in control circuits (key-operated switches, auxiliary position switches, protection logic), with position indicators on front panels. Visual barriers (protective screens) limit access to live parts when doors are open.

Feeder protection is implemented using microprocessor protection relays (or analog relays on request) with functions of instantaneous/definite-time overcurrent, overload and earth-fault protection; for motor feeders - undervoltage protection, autoreclosing (AR), and process interlocks. Provision is made for integration into DCS/SCADA systems, remote control, and tele-signals. Optional features include arc-flash light/current protection, key interlocks within a common key system, manual emergency trip mechanisms, and extended alarm packages.

Versions and options

• Incoming/feeder cubicles with a vacuum breaker - equipped with vacuum circuit breakers from leading manufacturers, current transformers (incl. zero-sequence CTs), surge arresters, and line/busbar disconnectors with earthing blades.
• Sectionalizing cubicles - with a vacuum breaker (SB) or a disconnector (SD), allowing multi-section busbar arrangements, ATS, and technological redundancy.
• VT cubicles - voltage transformers with fuses and busbar disconnector, busbar earthing; optional surge arresters on busbars.
• SST cubicles - 6(10)/0.4 kV station service transformer (typical 25/40 kVA), fuses, and busbar disconnector; optionally, the overhead incomer to the main breaker can be routed via the SST per single-line diagram.
• Climate/corrosion packages - compartment heaters and anti-condensation kits, enhanced coating systems, reinforced seals and louvers, dust-protection kits.
• Automation & telemetry - interfaces for IED/SCADA integration (Modbus/IEC 60870-5-104/IEC 61850 per project), remote control, time synchronization, energy metering.

Typical configurations

• CB cubicle - vacuum circuit-breaker cubicle: cable incomer / busbar incomer / overhead incomer.
• SD - sectionalizing disconnector cubicle; SB - sectionalizing breaker cubicle.
• VT - voltage-transformer cubicle (with busbar disconnector and fuses).
• SST - station service transformer cubicle (usually 25 or 40 kVA), other ratings per project.
• Additional - outgoing feeders, redundant incomers, ATS between sections, metering units, communication and telemetry panels.

By combining these cubicles, distribution systems of varying complexity are assembled - from a single incomer with several outgoing feeders to two-section switchgear with two incomers, a sectionalizing breaker, and distribution across multiple feeders considering process loads.

Compliance with standards

• EN/IEC 60721-3-4 - Environmental conditions, stationary use at non-weatherprotected locations (outdoor).
• IEC 60529 - Degrees of protection (IP code), typically IP34 for spray-proof enclosures.
• IEC 60068-2 series - Environmental testing (vibration, shock, transport).
• IEC 60071-1/-2 and IEC 62271-1 - Insulation coordination and common specifications for MV switchgear.
• IEC 62271-200 - AC metal-enclosed switchgear and controlgear 1–52 kV (applied per project/order to meet international requirements and certification).

Engaging contractors and partners

In manufacturing and implementation of KRUN-10 we are open to cooperation with manufacturers of electrical equipment (circuit breakers, current/voltage transformers, surge arresters, drives), as well as steelwork and cable plants. Contractors can perform painting, machining, harnessing, and cabinet assembly. For investors and integrators, we offer ready design solutions and unified specifications enabling rapid rollout of KRUN-10 serial production at your site, with localized supply chains and reduced lead times.

Documentation offered

The project package includes: single-line diagrams; functional and interconnection diagrams of primary and secondary circuits; wiring diagrams; cable schedules; bills of materials; test sheets; an explanatory note; the full set of manufacturing drawings (detail/assembly BOMs, purchased parts lists); 3D parametric models and CAM exchange formats (DWG/DXF, STEP/Parasolid). On request we provide working files for AutoCAD/Compass-3D/SolidWorks, as well as templates for automated wire/device marking. All documentation is adapted to your project requirements and your plant’s manufacturing capabilities.

Why work with us

-- No need to maintain a large engineering staff - you receive a complete documentation set for the product, suitable for execution by a mid-level engineer. 
- No need to build prototypes - our experience allows successful launch of serial production batches.
- Working to our documentation, your specialists will receive guidance on all nuances of KRUN-10 manufacturing.

For additional information on KRUN-10, please contact: inbox@proekt-energo.com

…as is well known, an error made at the design stage turns into 10-times the cost in manufacturing and 100-times in operation…

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