Purpose and scope of use

The K-201 “Volga” series is intended for the reception, distribution, switching, and selective protection of three-phase AC networks rated at 20 kV (highest system voltage - 24 kV) at 50 Hz; a 60 Hz variant is available by design. The cubicles are used in indoor substation switchgear, at power plants, and across industrial and infrastructure sites where high availability, internal-arc robustness, and safe operation are required. The modular architecture simplifies scaling of the lineup, while unified assemblies shorten manufacturing, delivery, and commissioning timelines.

“Volga” is equally suited to primary and secondary distribution: power-transformer incomers/outgoers, feeder panels, bus-section panels with AR/ATS, medium-voltage motor feeders (pumping, compressor, and fan drives), connections for capacitor banks and harmonic filters, as well as metering/measurement cubicles with VTs/CPTs. Operation is supported in radial and ring networks, with single- or double-busbar systems and sectionalizing. The design enables convenient operation in constrained electrical rooms - front access, expandable sections, and standard dimensional modules.

• - Industries: power & generation (GRES/CHP/CCGT), oil & gas (BS/PS, field package substations), mining & metals and machinery, chemical and pulp & paper, transport (metro, traction substations), utilities, data centers, renewable plants (20 kV export nodes), logistics terminals and ports.
• - Functions: selective protection & control, telecontrol, integration with DCS/SCADA, remote motorized operation; project options include digital communication backbones with channel/time redundancy.
• - Maintenance: single- or two-sided (per project), top/bottom cable entry, modularly expandable sections, service openings and removable panels to speed up routine work.

Service conditions

• - Environmental classification per EN/IEC 60721-3-3 (indoor, weather-protected); extended temperature/humidity solutions on request (heaters/ventilation, thermostat/hygrostat).
• - Indoor installation in atmospheres of normal corrosivity; on request, solutions for dusty areas and higher dust/dirt categories (enhanced sealing, filters).
• - Standard installation altitude up to 1000 m a.s.l.; above this, insulation and current-carrying parameters are verified in the project.
• - Seismic/vibration and mechanical impacts - per EN/IEC 60068-2 series (project-defined group).

Layout and design features

The cabinet frame is made of structural steel with an aluzinc (AZ) coating; exterior panels are powder-coated (base color RAL 7035). Assemblies are joined with structural blind rivets and threaded fasteners to maintain geometry, rigidity, and corrosion resistance throughout service life. The design provides directed ventilation paths and avoids through-air streams between MV compartments.

• - Busbar compartment - rectangular copper bars on insulators, per-panel sectionalizing with dielectric barriers; higher current densities and enhanced heat removal available by design.
• - Withdrawable unit compartment - truck with vacuum circuit-breaker/contactor/VT; shutter mechanism with interlocks and LOTO padlock provision; truck fixed in “test” and “service” positions.
• - Cable compartment - CTs, ZnO surge arresters, earthing switch, capacitive dividers/voltage presence indicators; cable entry from top or bottom via entry boxes/glands; minimum bend radius and service clearances observed for terminations.
• - Secondary compartment - protection, metering, control, and annunciation devices; rational harness routing and terminal rows, wire marking, and access to terminals without removing large items.
• - MV-compartment doors with heavy-duty hinges, gaskets, and inspection windows (by project); internal service lighting and service outlets - optional.

A common copper earthing bar runs along the cabinet base for inter-panel bonding; connection to the substation earthing grid is mandatory at least at two points. Unified bus/cable kits and assembly templates are provided for inter-section connections.

Safety and interlocking

• - Internal-arc readiness: each MV compartment has an independent pressure-relief duct with non-return check flaps and position limit switches; exhaust can be routed to a common top plenum or a safe room zone.
• - Optical/current arc-flash protection with accelerated tripping of incomer/section breaker (typical action < 0.02 s), with priority logic and channel self-monitoring.
• - Full set of mechanical, electrical, and key interlocks: truck movement only with door closed; MV-compartment doors blocked unless the earthing switch is ON; inter-panel key interlocking as specified.
• - Voltage-presence indicators (VPIS) on the front and test sockets for verification and phasing; provision for sealing operating elements and applying LOTO padlocks.
• - Additional measures: dual-channel position monitoring of the earthing switch, pressure sensors in arc-ducts, optional video monitoring of MV compartments.

Variants and options

• - Withdrawable unit with circuit-breaker/contactor, VT/CPT on the truck; special panels for sectionalizing, bus-bridges, AR/ATS.
• - Motor operators for the breaker truck and earthing switch for remote control; mimic diagram with status indication on the front and/or HMI panel.
• - Contact-temperature monitoring, vibration monitoring, MV-compartment video, anti-condensation heaters with thermostat/hygrostat, door-opening sensors.
• - DCS/SCADA integration: Modbus RTU/TCP, IEC 60870-5-104; by project - IEC 61850 (MMS/GOOSE), time sync via NTP/IRIG-B, network redundancy (PRP/HSR - as specified).
• - Bus bridges and transition panels to mate with existing switchgear; inter-row connections by busbar or cable; entries via top/rear cable ducts.
• - Extended options for IP rating and IAC category (A/FL/FLR - as specified); coating colors and corrosion-protection variants.

Typical cubicle configurations

• - Power-transformer incomer/outgoer, bus-section/bus-tie breaker, feeder, motor cell with start/ protection functions.
• - Metering/measurement cubicles with VT/CPT and/or current transformers; reactor cells, connections for capacitor banks and filter-compensation units.
• - Interconnection cubicles between rows/sections, transition panels to existing switchgear, cross-level connection nodes (as engineered).

Installation, commissioning, and service

• - Delivery in sections with factory settings applied; on site - busbar coupling, cable terminations, interlock verification, and functional tests.
• - Supervision and training: commissioning procedures, FAT/SAT checklists, typical testing programs for secondary circuits and protection IEDs.
• - Scheduled maintenance: visual inspection, torque checks, insulation condition control, firmware updates of protection IEDs; access to assemblies without taking the whole section out of service.
• - Maintainability: interchangeable trucks and devices, recommended/spare parts kits, unified sizes and connection interfaces.

Compliance with standards

• - IEC 62271-200 - metal-enclosed/metal-clad MV switchgear, LSC/PM categories, internal-arc classification IAC (A/FL/FLR - as specified), project option LSC2B-PM.
• - IEC 62271-100 - AC vacuum circuit-breakers;
• - IEC 62271-102 - earthing switches;
• - IEC 62271-1 - common specifications for high-voltage switchgear and controlgear.
• - IEC 60071-1 - insulation coordination and dielectric tests;
• - IEC 61869 - instrument transformers (as applied for CTs/VTs).
• - EN/IEC 60721-3-3 - environmental classification for stationary indoor use;
• - EN/IEC 60529 - degree of protection (IP) - as specified.
• - IEC 61243-5 - voltage presence indicating systems (VPIS).

Technical data

We offer documentation for manufacturing the 20 kV K-201 “Volga” switchgear:

- Pre-tender package: technical description, diagrams, inquiry sheets, confirmation of manufacturability.
- Working drawings, 3-D models, and a full design dossier for production at your facility, with supply-chain cooperation on assemblies if required.
- Fast adaptation of documents to project requirements and your plant’s capabilities.
- Transition solutions for interfacing with installed third-party equipment and expanding existing MV rooms.

Why work with us:

- No need to maintain a large highly qualified engineering staff - the documentation set is targeted at engineers of average qualification.
- Series launch without pilot prototypes - we rely on proven technical solutions and standardized assemblies.
- Hands-on support for your team on all aspects of manufacturing the K-201 “Volga”.

For additional information on the 20 kV K-201 “Volga” switchgear contact: inbox@proekt-energo.com

...as is well known, an error made at the design stage results in tenfold costs in manufacturing and a hundredfold in operation...

PDF - Download K-201 “Volga” Technical Information

Purpose and scope of application

The K-224 “Omega” series of medium-voltage switchgear is intended for receiving, distributing, switching, and selective protection of three-phase AC power at a rated voltage of 20 kV (maximum system 24 kV) and frequency 50 Hz (60 Hz on request). The switchgear is used in indoor substations of package transformer substations, in utility and industrial distribution substations, for auxiliary power systems of power plants, and at municipal and infrastructure facilities.

The metal-clad concept with a withdrawable vacuum circuit-breaker and segregated compartments confines the effects of any internal arc to a single compartment and enables safe maintenance. The modular architecture allows flexible configuration of feeder schemes, top/bottom cable entry, and one-sided/two-sided maintenance to suit the site requirements.

Typical applications include primary and secondary distribution at main and distribution substations, supply of 6-20 kV outgoing cable feeders, bus-sectioning and automatic transfer between bus sections, transformer incomers/outgoers, starting and protecting medium-voltage motors (pump stations, compressor rooms, large fans), connection of power-factor correction banks and harmonic filter banks, as well as auxiliary service transformers/voltage transformers for metering and measurements. “Omega” panels are equally effective in radial and ring networks, with single- or double-bus arrangements, including “incomer - section - incomer” schemes.

Industry users: upstream/downstream oil & gas (field MV substations, gathering/booster stations), mining & metals (concentrators, rolling mills), power & heat (TPP/CHP, CCPP, micro-generation), transport and urban infrastructure (metro, traction substations, airports, medical and business centers), data centers, and RES sites (wind/solar - 20 kV grid-integration nodes). For critical loads (reliability categories I and II), functions such as AR/ATS, remote control, telecontrol, and SCADA/DCS integration are supported.

Layout and construction

The cabinet is made of galvanized steel; elements are joined with high-strength blind steel rivets. The internal volume is divided by solid metallic and insulating partitions into independent compartments, each equipped with an individual pressure-relief duct with limit switches.

• - Withdrawable unit (circuit-breaker) compartment with shutter mechanism and padlocking capability in the test position.
• - Cable compartment: current transformers, surge arresters, earthing switch, capacitive dividers/voltage-presence indicators; top/bottom cable entry.
• - Busbar compartment: bare copper busbars; take-offs may use solid insulation as specified.
• - Relay/low-voltage compartment (secondary circuits) for protection & control IEDs, control, annunciation, and revenue metering.

For convenient service access, the floor of the withdrawable-unit compartment is removable. A common copper earthing bar runs along the cabinet base, bonding all panels in the section; it shall be connected to the substation earthing grid at no fewer than two points.

Safety and interlocks

• - Built-in arc-flash protection with accelerated tripping of incomer/section breakers (typical clearing time ≤ 0.2 s) with current/voltage supervision to avoid mis-operations.
• - Mechanical, electrical, and key interlocks: prohibition on opening MV-compartment doors with the ES open or the truck in the in-service position; truck movement only with the door closed.
• - Spring-operated high-speed earthing switch with visible position indication and status output to the front panel/P&C system.
• - Pressure-relief flaps for each MV compartment to vent arc products in a safe direction.

Configurations and options

• - Panels with auxiliary service transformer (AST) and/or voltage transformers on a withdrawable truck; interlocks preventing truck movement with the AST LV breaker closed.
• - Motorized drives for the truck and earthing switch for remote operation; integration of optical arc protection, contact-temperature monitoring, and mimic indication.
• - Bus-tie bridges and transition panels for coupling to existing switchgear, including inter-row connections.

Standards compliance

• - IEC 62271-200 - metal-enclosed/metal-clad MV switchgear, LSC/PM categories; internal-arc classification IAC (A/FL/FLR - as specified).
• - IEC 62271-100 - AC circuit-breakers (vacuum);
• - IEC 62271-102 - earthing switches and their drives;
• - IEC 60071-1 - insulation coordination and dielectric tests;
• - EN/IEC 60721-3-3 - environmental conditions (indoor, weather-protected);
• - IEC 60529 - degrees of protection (IP);
• - IEC 61000-6-2 / 61000-6-4 - EMC for industrial environment (immunity/emission);
• - IEC 60068-2 - environmental/mechanical tests (vibration, shock, temperature, humidity).

Technical data

We offer documentation for manufacturing the 20 kV KRU K-224 “Omega”:

• - Base tender package: technical description, principal single-line diagrams, and data sheets confirming manufacturing readiness.
  - Full production dossier: drawings, 3D models, and all design documentation required to start manufacturing at your site; if needed, we will arrange subcontracting for assemblies and parts.
  - Rapid document adaptation to the specific project requirements and your plant’s process capabilities.
  - Transition solutions for integrating installed third-party equipment, ensuring proper interfacing and extension of the switchgear line-up.

Why work with us:

• - No need to maintain a large senior engineering staff: the documentation set is tailored to a mid-level engineer.
  - No prototype stage: we launch series using proven technical solutions.
  - Advisory support for your specialists on all aspects of manufacturing KRU K-224 “Omega”.

For additional information on the 20 kV KRU K-224 “Omega”, contact: inbox@proekt-energo.com

…and, as is well known, an error made at the design stage results in a tenfold cost at manufacturing and a hundredfold during operation…

PDF - Download technical information for the 20 kV KRU K-224 “Omega”

Purpose and application

The K-203 switchgear bays are intended for receiving, distributing, switching, and selectively protecting three-phase AC power at a rated voltage of 20 kV (highest system voltage 24 kV) and frequency 50 Hz (60 Hz optional per project). Applications include indoor substations (MV switchrooms), factory-built package substations, station-service boards of power plants, industrial distribution points, and utility/infrastructure sites.

K-203 belongs to air-insulated switchgear (AIS) per IEC 62271-200 with sectionalized architecture, and is intended for operation in 6-24 kV networks with various neutral regimes (isolated, grounded via arc-suppression reactor or active resistor). The design achieves the required service continuity categories LSC and partition classes PM/PI (as specified), allowing safe work in one compartment while adjacent compartments remain energized in line with the user-oriented classification of the standard.

• - Networks with an isolated neutral or a neutral grounded via arc-suppression reactor / active resistor.
• - Typical schemes: transformer incomers/outgoers, bus section/coupler, outgoing cable feeders, capacitor/reactive-power compensation feeders, metering/measurement, reserve incomers.
• - Sectors: power & utilities, oil & gas, mining & metals, machinery, transport & logistics, water and district-heating utilities, large commercial & data-center sites, urban infrastructure.
• - Short-circuit and internal-arc levels are project-defined; configurations comparable with best-in-class AIS 24 kV are available (IAC AFLR up to 25-31.5 kA 1 s; LSC2B; PM partitions).

Layout and construction

The enclosure is made of steel with an Aluzinc coating; external panels are powder-coated (project RAL) for long-term corrosion resistance. The internal volume is divided into independent compartments by solid metallic and insulating partitions; each compartment has its own pressure-relief duct to localize internal-arc effects (upward venting through flaps/ducts). The design allows front servicing, "back-to-wall" installation, and section coupling without rear access, simplifying retrofit projects.

• - Truck (withdrawable unit) compartment for CB/contactor/VT, with shutter mechanism, mechanical interlocks, and guides for precise positioning; "test/check/service" operations are performed with the door closed.
• - Cable compartment: CTs, surge arresters, earthing switch with making capacity (class E per IEC 62271-102), top/bottom power-cable entries (per project), provision for voltage-presence indicators and test sockets.
• - Busbar compartment - copper/aluminium busbars, bay-by-bay sectioning by insulating partitions, optional bus-duct bridges/taps for inter-row connections.
• - Secondary (LV/controls) compartment - protection & automation IEDs and SCADA, telecontrol terminals, meters, terminal strips, marshalling panels; support for IEC 61850 / IEC 60870-5-104 (as specified); space for contact-temperature and partial-discharge monitoring modules.
• - Directed pressure-relief flaps and reinforced hinges/locks on HV-compartment doors for safe arc-energy exhaust.

Safety and interlocking

• - Internal-arc classification per IAC (access class A for operators; protection directions F/L/R - front/side/rear) with upward exhaust; typical configurations - AFLR for 1 s (fault current per spec). IAC definitions per IEC 62271-200.
• - Comprehensive mechanical/electrical interlocks: truck movement only with door closed; earthing switch cannot close with truck in the service position; HV-compartment access blocked unless earthing is applied; truck positively latched in "test/check/service" positions.
• - Optical/current-based arc-flash protection with accelerated tripping of incomer/section CBs; optional dedicated arc-protection modules in cable and busbar compartments to minimize arc energy.
• - Voltage-presence indicators on the front; sockets for phasing/tests; key interlocks and/or key-transfer systems for process-safe sequences.
• - Degrees of protection per IEC 60529 (typical front IP3X/4X; secondary compartments up to IP4X/54 per project).
• - "Closed-door operation" and "logical interlocking" principles follow best practices for AIS 24 kV.

Variants and options

• - Bays: incomers/section couplers, outgoing feeders, measurement/metering, VT/SST on a truck, feeders for capacitor banks/reactive-power units (including detuned), AR/ATS.
• - Switching devices: vacuum circuit-breakers (ratings per project), vacuum contactors for frequent operations, load-break switches per IEC 62271-103 (as specified).
• - Motor operators for the truck and earthing switch for remote control; front-panel mimic with position indication and alarms; SCADA/PCS integration readiness.
• - Systems: joint-temperature monitoring (busbar and cable lugs), partial-discharge monitoring, HV-compartment CCTV, anti-condensation heaters, smart micro-climate sensors.
• - Transition bays, bus-duct bridges, and cable jumpers for interfacing with existing switchgear; transportable sections for faster site installation.
• - Environmental classes per EN/IEC 60721-3-3 (replaces GOST 15150 U3; cold-climate options per project), seismic capability per spec, high-altitude execution; corporate color schemes.
• - Regulatory note: when designing AIS 24 kV in the EU, consider restrictions on new MV equipment using SF₆ as of 01-01-2026 (Regulation (EU) 2024/573); K-203 uses vacuum CBs and air insulation.

Standards compliance

• - IEC 62271-200 - metal-enclosed/metal-clad switchgear, LSC categories and partition classes PM/PI, internal-arc classification IAC (A/FL/FLR - per spec).
• - IEC 62271-100 - AC circuit-breakers (vacuum); IEC 62271-106 - contactors;
• - IEC 62271-103 - load-break switches.
• - IEC 62271-102 - earthing switches (classes M1/M2, E1/E2 - per spec).
• - IEC 60071-1 - insulation coordination and dielectric tests.
• - EN/IEC 60721-3-3 - environmental conditions for weather-protected indoor locations (replaces GOST 15150);
• - IEC 60529 - degrees of protection (IP code).
• - ISO 12100 / IEC 60204-1 (as applicable) - machinery safety / electrical equipment of machines.
• - Target safety/performance levels benchmarked against leading AIS 24 kV solutions (typ. IAC AFLR, LSC2B, PM) used in primary distribution.

Technical data

We offer documentation for manufacturing 20 kV K-203 switchgear:

- Preliminary tender package: technical description, diagrams, questionnaires, manufacturability confirmation.
- Working drawings, 3-D models, and a complete design dossier for production at your facility; we can arrange supplier cooperation for assemblies if needed.
- Prompt adaptation of documentation to the project requirements and your manufacturing capabilities.
- Transition solutions for interfacing with installed third-party equipment and expanding existing switchgear.

Benefits of working with us:

- No need to maintain a large team of senior engineers - the documentation set is tailored for a mid-level engineer.
- Series launch without prototypes - we use proven technical solutions.
- Full support for your team across all aspects of manufacturing K-203 switchgear.

For additional information on 20 kV K-203, 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 20 kV K-203 technical information