KYN-28A Medium-Voltage Switchgear 6(10) kV

KYN-28A is an upgraded line of metal-clad switchgear cubicles for power distribution, sectionalizing, and protection of 6-10 kV medium-voltage networks (50 Hz). The switchgear collects and distributes power at primary substations, plant substations, and infrastructure supply centers; it also serves as a platform for station-service (auxiliary) panels and revenue-metering cubicles. Schemes are suitable for systems with both an isolated and a compensated (resonant-grounded) neutral.

The "A" revision features reinforced arc-gas exhaust, optimized busbars, and a dedicated mounting area for digital IEDs per IEC 61850 Ed.2. The VCB truck (vacuum circuit-breaker) can be racked to the test/service position within 60 s by a single operator without de-energizing adjacent sections. The front door uses twin-seal gaskets that prevent hot-gas ejection during an internal arc fault.

The enclosure is made of galvanized steel with an Aluzinc coating; external panels are powder-coated to RAL 7035. Structural blind rivets maintain geometry and provide high shear strength, which is critical under internal short-circuit stress.

Standards and compliance

IEC 62271-200 - type-tested, internal arc classification IAC AFL up to 31.5 kA;
IEC 62271-100 - vacuum circuit-breakers up to 12 kV;
IEC 62271-102 - earthing switches with spring operating mechanism;
IEC 60071-1 - insulation coordination (levels and test withstands);
EN/IEC 60721-3-3 - environmental conditions (replaces GOST 15150 U3/T3); IEC 60529 - IP 31/41 (higher on request).

Where KYN-28A is used

6-10 kV MV switchgear at 110/35 kV substations and industrial main substations;
Diesel/gas-engine plants, CHP & mini-CHP, and renewable power evacuation nodes;
Water-treatment plants, metro systems, airports, data centers, logistics hubs;
Replacement/upgrade of legacy KSO/GIS lineups with adapted buswork and cable entries;
Revenue metering and precision measurement points in medium-voltage networks.

Service conditions

Indoor heated rooms at -25 ... +40 °C; below -25 °C, switchroom heating is mandatory;
Altitude ≤ 1000 m; above this, apply insulation/cooling recalculation (derating);
No explosive atmospheres and no conductive dust (per EN/IEC 60721-3-3 conditions);
Mechanical stress per EN/IEC 60721-3-3; vibration resistance 0.5 g in the 1-30 Hz range;
Standard IP 31; IP 41 or IP 54 available on request.

Design features

Four-compartment layout: busbars · circuit-breaker · cable · protection/auxiliaries;
Arc-gas exhaust ducts with isolated channels and pressure-relief flaps;
Composite shutters with key interlocking;
Spring-operated earthing switch with closing force < 150 N for safe manual operation;
Option: motor operators for the CB and earthing switch for remote SCADA control.

Variants and options

VCB 630...3150 A, up to 31.5 kA; CTs 5P20 / 10P, cast-resin VTs and ZnO surge arresters;
Bays: incomer, bus coupler, feeder/line, VT cubicle, busbar bypass;
Top or bottom cable entry; bus-duct bridges up to 4000 A;
IEDs with MMS/GOOSE (IEC 61850) and DLMS for revenue metering;
Arc-flash sensors, temperature tags, video monitoring system.

Reliability and lifetime

Internal-fault containment ≤ 100 ms; overpressure limited to < 5 kPa;
CB mechanical endurance - 30 000 operations; enclosure service life - ≥ 25 years without repainting;
Coating corrosion resistance - 720 h salt-spray (ISO 9227);
100% outgoing QC of current-carrying joints (γ-defect ≤ 1 ppm).

Technical data

Rated voltage, kV	6; 10
Highest system voltage, kV	7.2; 12
Rated current of main circuits, A	630-3150
Rated busbar current, A	1250-3150
Short-time withstand current (3 s), kA	20-31.5
Peak withstand current, kA	51-81
Service access	single- or double-sided
Insulation level (IEC 60071-1)	normal
Environmental classification (EN/IEC 60721-3-3)	EN/IEC 60721-3-3
Degree of protection (IEC 60529)	IP 31 (up to IP-54 on request)
Dimensions, mm - width - depth - height	800 / 1000 1500 / 1700 2300

Documentation and production support for KYN-28A

Tender package. We promptly deliver single-line diagrams, data sheets, and explanatory notes for tenders and technical acceptance by the client.

Working drawings & digital models. We supply 3-D STEP / DWG, bills of materials (BOM), secondary wiring diagrams, cable schedules, and quality certificates for series production at your facility.

Contract manufacturing of assemblies. When needed, we place metalwork, doors, and operating mechanisms with certified partners, leaving final assembly and factory tests with you.

Adaptation to existing equipment. We design equivalent cubicles to "match" third-party busbars and cable entries while preserving the overall substation architecture.