KRU-2-10 is a line of metal-clad medium-voltage cubicles for receiving, distributing, and switching three-phase power at 6/10 kV, 50 Hz (operation at 60 Hz available on request). Intended for systems with an isolated neutral or a neutral grounded through an arc-suppression reactor/active resistor, ensuring correct protection behavior and network stability under single-phase earth faults. The series is produced for domestic and export markets for indoor substations at utility and industrial sites in oil & gas, mining & metallurgy, transport, public utilities, data centers, and infrastructure hubs. Environmental classification follows EN/IEC 60721-3-3 (replaces GOST 15150 U3).

The base design is a welded steel enclosure (project-specified RAL) reinforced with stiffeners. The interior is divided by solid metallic and insulating barriers into independent compartments: circuit-breaker truck, cable, busbar, and protection/auxiliary (LV). A shutter mechanism automatically closes the fixed contacts when the truck is moved to the test/maintenance position; shutters can be locked for safe work. The metal-clad concept localizes internal-arc effects within a single compartment, routes overpressure via directed relief, and provides a protected front-raising personnel safety and equipment availability.

A withdrawable vacuum circuit-breaker is used as the main switching device (endurance class M2/E2/C2 as specified). Mechanical and electrical interlocks prevent mal-operations; a fast earthing switch with making capacity (make-proof) is provided, as well as voltage-presence indicators. Optional motorization of the CB truck and earthing switch enables remote transfer to service/test/grounded positions. Top or bottom cable entry can be implemented, with lugging/termination of power cables, installation of CTs/VTs, ZnO surge arresters, and monitoring devices; cable testing is permitted in the test position with main contacts isolated.

Cubicles integrate with microprocessor IEDs for protection/automation (autoreclosing/automatic transfer, overcurrent/voltage/distance protection, optical arc protection) and support telecontrol protocols and SCADA integration. Various bus schemes can be implemented (single bus with section coupling; bypass on request), using copper or aluminium busbars with bay-by-bay sectioning via bushing insulators. The design supports front-side routine operations and rear access for installation/maintenance; removable rear panels and compartment lighting simplify service. Standard supply includes anti-condensation heaters, screened raceways for secondary wiring, and directed pressure-relief flaps.

• - Typical feeders: incomers, bus couplers, outgoing feeders, transformer feeders, metering/measurement, VT/SA, auxiliaries.
• - Safety: internal arc classification (IAC - per spec), shutter mechanism, interlocks, spring-operated earthing switch, voltage indicators.
• - Integration: protection IEDs, telecontrol/SCADA, top/bottom entries, motorized drives, copper/aluminium busbars.
• - Operation: front-side operations, rear-side service, removable panels, anti-condensation heating, shielded secondary wiring routes.

Applications

KRU-2-10 is used at both primary and secondary distribution levels:

• Indoor MV switchrooms (6-10 kV) at package substations and distribution points for urban and industrial networks;
• Substations of generation/transmission companies; station service systems of power plants;
• Industrial sites (oil & gas, mining & metals, machinery), public utilities (pumping stations, booster PS, substations), data centers;
• Retrofits of existing switchgear, integration with installed busbars/cable routes.

Service conditions

• Indoor installation; altitude up to 1000 m above sea level;
• Temperature range: from -25 °C (with relay-compartment heating) / -5 °C (without heating) to +40 °C; at +35 °C and above, a ~5% derating may apply for 1600 A and 3150 A ratings;
• Non-hazardous area, free from conductive dust and aggressive vapors/gases (environmental conditions per EN/IEC 60721-3-3).

Design features

• Compartmentalization: cable · CB truck (withdrawable unit) · busbar · protection/LV compartment;
• Arc-fault mitigation (arc sensors/relays, directed pressure relief) to prevent damage under short circuits;
• Configurations: with truck, without truck, or mixed (part of equipment on the truck);
• Equipment on the truck: vacuum CBs, VTs, station-service transformers (SST) up to 5 kVA, fuses for remote SST protection;
• Busbars and links in copper/aluminium; sectioning and buswork per project;
• Top or bottom cable entry;
• Mechanical/electromagnetic interlocks per safety logic and industry standards.

Scope and options

• Bus inlets, ducts, and side/rear add-on cabinets for transformer connections (custom-engineered);
• Bus bridges/jumpers between rows in the same room; transition cubicles for interfacing with existing switchgear;
• Spare withdrawable units with circuit-breakers, service trucks, DC supply/auxiliary cabinets;
• Spare parts kit, tools, and service accessories.

Standards compliance

• IEC 62271-1 - common specifications for MV switchgear and controlgear;
• IEC 62271-100 - AC circuit-breakers; IEC 62271-102 - disconnectors and earthing switches;
• IEC 61869-2/-3 - current and voltage transformers; IEC 60529 - degrees of protection (IP code);
• IEC 61000-6-2/-6-4 - EMC (industrial immunity/emissions) [replacing GOST R 51317.6.2/6.4].

Reliability and serviceability

• Arc confinement within a compartment with directed pressure relief - adjacent bays remain intact;
• Interlocks prevent incorrect operations; shutters block access to live contacts;
• Metallic raceways for secondary circuits - improved EMC, neat routing, and maintenance access;
• Galvanized steel with powder coating - long-term corrosion resistance.

Technical data