The single-front metal-enclosed switchgear series KSO-298 (6–10 kV) is intended for the reception, distribution, and switching of three-phase 50 Hz AC in systems with isolated, effectively earthed, or solidly earthed neutrals. The cubicles are used in indoor MV switchrooms of package transformer substations (PTS), at industrial and power-plant substations, on municipal infrastructure and commercial sites. The design suits both permanent switchrooms and factory-built modular blocks, enabling short supervision/commissioning time on site.

Purpose and application

KSO-298 forms incomer, bus-section, and feeder bays in medium-voltage lineups. Typical tasks: connection of 6–10 kV power transformers; switching of cable/overhead lines; busbar sectionalizing with automatic transfer (ATS); auxiliary services supply; revenue/technical metering; telemetry to SCADA/DCS. Transition panels and unified interfaces simplify retrofit into existing rooms without long outages.

Service conditions

Baseline environmental classification - EN/IEC 60721-3-3 for stationary use at weather-protected locations (indoor). The enclosure degree of protection is IP20 per IEC 60529, protecting personnel from access to hazardous live parts and the equipment from large solids; local IP upgrades for selected zones are available subject to thermal checks. Where required, variants for other climatic regions can be engineered, with altitude corrections to clearances and test levels per general MV switchgear rules.

Layout and design solutions

Two enclosure concepts are available: (a) a welded structural-steel frame with powder-polymer coating for high mechanical rigidity; (b) a bolted sheet-steel construction with Aluzinc/galvanized panels on non-welded fasteners for rapid assembly and easy service. The cubicle is divided into functional compartments: the apparatus compartment (circuit-breaker, disconnector/earthing switch), busbar compartment (main busbars), cable compartment (entries, terminations, CTs), and a low-voltage compartment (protection/automation IEDs, metering, terminal boards). Viewing windows on the front allow checking device positions; a service light and a socket for a portable lamp are provided.

For measuring circuits we recommend instrument transformers to the IEC 61869 series (Parts 2 and 3 for CTs and VTs), ensuring correct accuracy classes, overload/short-time capability, and compatibility with modern protection IEDs.

Safety and interlocking

KSO-298 implements coordinated mechanical interlocks that prevent hazardous operations: blocking operation of the disconnector with the breaker closed; blocking closing of the earthing switch with the disconnector closed; blocking closing of the disconnector onto an earthed circuit; blocking door opening unless the feeder is earthed. All breaker operations are performed with the HV door closed, reducing operator risk. Sequences, endurance of operating mechanisms, insulation distances and type-test sets follow the general requirements of IEC 62271-1 together with product parts IEC 62271-100 (AC circuit-breakers) and IEC 62271-102 (disconnectors and earthing switches). For higher safety requirements, internal-arc-classified designs (IAC) to IEC 62271-200 with accessibility/direction codes (e.g., IAC AFLR 20 kA 1 s) are available, with pressure-relief paths to discharge hot gases into safe areas.

Variants and options

The KSO-298 range covers incomers, bus-sections (with breaker or disconnector), outgoing feeders, VT/CT, metering, auxiliary-services, and bus-coupler bays. Options include:
- vacuum circuit-breakers meeting IEC 62271-100 switching-duty requirements;
- manual and motor operators, fixed or withdrawable arrangements;
- modern microprocessor protection IEDs (differential, directional, autoreclose/ATS) and disturbance recorders;
- digital integration per IEC 61850 (MMS/GOOSE/SMV), incl. routable profiles (R-GOOSE/R-SV) for distributed architectures;
- enhanced anti-corrosion systems, thermal insulation/heaters, arc-flash sensors, partial-discharge monitoring, temperature sensing on cable lugs and busbars;
- seismic design, extended spare-parts kits, and standardized bus links.

Typical configurations

For 6–10 kV lineups, typical KSO-298 schemes include:
1) Incomer - transformer or HV line connection with metering and ATS;
2) Bus-section - bus splitting for maintenance and fault-ride-through;
3) Feeder - outgoing cable/overhead feeders with full protection and current/voltage diagnostics;
4) VT/CT panel - supply of measuring circuits, energy metering and condition monitoring;
5) Auxiliary services - control-power and switchroom life-support systems;
6) Bus coupler - inter-section links for flexible network topology.

Standards and compliance (6–8 key references)

• IEC 62271-200 - metal-enclosed switchgear 1–52 kV: construction, type/routine tests, internal-arc classification (IAC) and accessibility types.
• IEC 62271-1 - general requirements (service conditions, insulation levels, type tests).
• IEC 62271-100 - AC circuit-breakers: duties, making/breaking capability and verification tests.
• IEC 62271-102 - AC disconnectors and earthing switches: drives, interlocking, endurance.
• IEC 60529 - degrees of protection by enclosures (IP code), with IP20 commonly applied for access zones.
• EN/IEC 60721-3-3 - environmental classification for stationary use at weather-protected locations (indoor).
• IEC 1516.3 equivalents replaced here by insulation coordination and dielectric test references within IEC 62271-1/-200; for instrument transformers use IEC 61869-2/-3.
• IEC 61869-2/-3 - instrument transformers (CTs/VTs) for protection and metering.

Integration into digital substations and automation systems

On request, KSO-298 is supplied with IEC 61850-enabled IEDs: logical-node data models, MMS for station-bus services, and GOOSE/SMV for high-speed protection and measurement messaging on the process bus. This reduces copper wiring, raises observability, and simplifies modernization.

Operation and maintenance

The “operate-with-door-closed” principle minimizes operator risk and speeds routine switching. Modular, unified assemblies simplify spares logistics and expedite restoration after faults. Where required, arc-flash protection, temperature sensors on cable lugs and busbars, and maintenance plans based on breaker duty statistics and digital disturbance records are applied.

Technical data

We offer documentation for manufacturing KSO-298:

- Pre-tender technical package (questionnaires, specifications, one-line/functional diagrams) to accelerate compliance checks and quotation preparation.
- Working drawings, 3-D models and a complete design set to launch KSO-298 production at your facility. If you lack in-house capacity for enclosures/busbars, we will place fabrication with certified partners; assembly, routine tests and installation are performed at your works.
- Project adaptation of drawings to corporate standards and local procedures, plus guidance on IEC/GOST protocols (e.g., dielectric tests per IEC 62271-1/-200 and factory functional tests).

Why work with us:

- No need to maintain a large team of senior engineers: the document set is structured for confident use by a mid-level engineer.
- Serial launch without a pilot build: proven modules and test programs allow immediate series production.
- Expert support for digital integration: assistance with IED setup and IEC 61850 (MMS/GOOSE/SMV), SCADA/HMI interfacing and station/process-bus architectures.

For additional information on KSO-298 please contact: inbox@proekt-energo.com

Design-stage errors multiply fabrication and lifecycle costs. Correct specification to IEC 62271, proper CT/VT selection to IEC 61869 and adherence to IP/environmental classes (IEC 60529, EN/IEC 60721-3-3) significantly reduce project risk.

PDF - Download KSO-298 technical information