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