Purpose and application

The KRU VM-1 series of medium-voltage switchgear is designed for receiving, distributing, switching, and selectively protecting three-phase AC power at rated voltages 6; 10 kV and frequency 50/60 Hz. VM-1 cubicles operate in systems with an isolated neutral as well as in systems grounded via an arc-suppression reactor or an active resistor, ensuring the required levels of reliability, safety, and availability for MV distribution networks.

Applications cover the full range of utility and industrial facilities: from station-service boards of power plants and node substations of transmission operators to plant switchrooms, infrastructure hubs, and commercial sites. In typical configurations, VM-1 covers incomers, bus section/coupler bays, outgoing feeders, transformer feeders and tie/reserve couplings, as well as metering and measurement bays. The metal-clad architecture with a withdrawable vacuum circuit-breaker, segregated compartments (cable, circuit-breaker, busbar, protection/LV), and a comprehensive interlocking system localizes internal faults within a single compartment and enables safe operations.

KRU VM-1 integrates with modern microprocessor protection and automation IEDs (autoreclosing, automatic transfer, overcurrent/voltage/distance protection, optical arc-flash protection), supports telecontrol and SCADA integration. Design options include single- or double-sided service access, top/bottom cable entry, copper or aluminium busbars, and various bus schemes (single, sectionalized, sectionalized with bypass). As specified, the CB truck and earthing switch can be motorized for remote operations and interlocked procedures.

VM-1 is used by utilities and grid operators; in oil & gas, mining and metallurgy, chemical and pulp & paper industries; in transport (metro, rail hubs), data centers, healthcare, and large logistics complexes. A separate focus area is distributed generation and RES (wind/solar), cogeneration, and microgrids, where VM-1 is applied for generator feeders, reactive-power compensation units, and energy-storage systems. The portfolio supports both greenfield projects and staged retrofits of existing switchgear.

Operating conditions assume indoor installation with controlled environment; anti-condensation measures are provided (heaters in LV/relay sections), directed pressure-relief flaps, arc-resistant front doors, and lockable shutters. For maintainability and uptime, access to serviceable parts follows maintenance procedures, and the routing of power and control cables is arranged in shielded raceways for EMC.

• - Typical functions: incomer/sectionalizer, outgoing feeders, power-transformer feeders, metering/measurement, VT/SA, station service.
• - Industries: generation and networks, oil & gas, mining & metals, chemicals & pulp-paper, transport & utilities, commercial & data-center sites, RES/DG/microgrids.
• - Key advantages: internal arc classification (IAC per spec), robust mechanical/electrical interlocking, modular layouts, readiness for digital protection and dispatching, safe and convenient maintenance.

Design and compartments

A metal-clad design with a withdrawable vacuum circuit-breaker and full compartmental segregation (CB, cable, busbar, protection/LV) confines fault effects to one compartment. Mechanical and electrical interlocks prevent incorrect operations; a lockable shutter mechanism covers the main contacts in the test and maintenance positions of the truck.

Functions and protection/automation

- Typical bays: incomer, bus section/coupler, outgoing feeders, metering/measurement, VT/SA, station service.
- Protection & automation: autoreclosing (AR), automatic transfer (ATS), overcurrent/distance protections, optical arc-flash protection, telecontrol and SCADA integration.
- Compatibility with a wide range of 6-10 kV vacuum circuit-breakers subject to interface compliance.
- Modular architecture: selectable cable-entry direction (top/bottom), single- or double-sided service.

Materials and safety

The enclosure is made of steel with an Aluzinc coating; façade elements are powder-coated (RAL per project) for long-term corrosion resistance. Bay-by-bay metallic and insulating partitions protect adjacent compartments. Directed pressure-relief flaps and arc-resistant doors support the specified IAC class.

Compartment equipment

- Protection/LV compartment: protection IEDs, metering/measurement devices, HMI; cable routes in protective raceways.
- CB compartment: truck with circuit-breaker/contactor/VT and manual or motorized mechanism; shutters lockable in the closed position.
- Busbar compartment: air insulation, copper/aluminium busbars, sectioning via bushing insulators; bus-ducts/cable jumpers between lineups.
- Cable compartment: CTs (including zero-sequence), surge arresters, spring-operated earthing switch; connection of multi-core and single-core cables.

Standards compliance

- IEC 62271-1 - Common specifications for MV switchgear and controlgear (terminology, tests, climatic, temperature rise, dielectric).
- IEC 62271-200 - AC metal-enclosed/metal-clad switchgear 1…52 kV: LSC/PM categories, internal arc classification IAC (class/current/time per spec).
- IEC 62271-100 - AC circuit-breakers (vacuum); IEC 62271-102 - Earthing switches and operating mechanisms.
- IEC 62271-103 - Switches (load-break); IEC 62271-105 - Switch-fuse combinations; IEC 62271-106 - Contactors/starters (if used).
- IEC 61869-2 / IEC 61869-3 - Instrument transformers (CTs/VTs).
- IEC 60071-1 - Insulation coordination (levels and dielectric tests).
- IEC 60865-1 - Short-circuit forces and busbar mechanical design.
- IEC 61000-6-2 / IEC 61000-6-4 - EMC for industrial environments (immunity/emissions).
- IEC 60068-2-1 / -2-2 / -78 - Climatic tests (cold, dry heat, damp heat steady state).
- IEC 60529 - Degrees of protection (IP code).
- EN/IEC 60721-3-3 - Environmental conditions for weather-protected indoor locations (replaces GOST 15150 U3).

Specific LSC/PM classes, IAC parameters (current/time/sides AFL/AFLR), LI/AC levels, IP and EMC are set in the specification and confirmed by type/routine test reports.

Technical data

We offer documentation for manufacturing KRU VM-1:

- Preliminary technical package for tenders to manufacture KRU VM-1: compliance review versus specification and questionnaires.
- Working drawings, 3-D models, and a complete process dossier for in-house production of KRU VM-1. If capacity is limited, we can arrange contract fabrication of subassemblies; you perform final assembly and installation.
- Adjustment of design packages to project requirements and to your manufacturing capabilities.
- Engineering of compatible solutions where other manufacturers’ equipment is present on site (transition bays, bus-duct bridges, cable inserts).

Benefits of working with us:

- No need to maintain a large team of senior engineers: you receive a complete, build-ready documentation set suitable for implementation under mid-level supervision.
- Series launch without prototypes: proven solutions allow immediate transition to serial production.
- Full support: consulting on fabrication, commissioning, and operation of KRU VM-1.

For additional information on KRU VM-1, contact: inbox@proekt-energo.com

...and, as is well known, an error made at the design stage costs 10× in manufacturing and 100× in operation...

PDF - Download KRU VM-1 technical information