6 kV КРУ-Е switchgear in the КМ-1Ф frame size: 16 cubicles replacing an obsolete series

The task

The site ran a 6 kV switching station built on КМ-1Ф series cubicles. The series is out of production: oil switching, electromechanical protection, and effectively no spare parts on the market.

Replacing the station with a different frame size would have dragged the building with it: different cubicle dimensions mean a different cable-entry grid, a different busbar layout, civil works.

The client needed to keep the frame size so that new cubicles would drop into the footprint of the old ones — while getting fully modern internals.

The solution

We built КРУ-Е in the КМ-1Ф frame size — a design compatible with the mounting footprint of the old series, with entirely contemporary contents.

• Frame size. The cubicles reproduce the КМ-1Ф installation dimensions: they fit the existing room grid without rebuilding the cable infrastructure.
• Switching. Vacuum circuit breakers on a withdrawable truck — rolled out on a carriage and serviced outside the cubicle. That is the key difference from the old series: maintenance without dismantling the cubicle.
• Protection. Microprocessor protection relays on every cubicle front, one operator interface across the row.
• Metering. Current transformers with two secondary windings: class 0.5S for metering and 10P for protection.
• Main circuits. 1600 A busbars — headroom above the 630 A bay rating, so the row can carry future load growth.
• Documentation. Each of the 16 cubicles has its own factory passport with a serial number and a bill of components.

The series product card: КМ-Е cabinets (КМ-1Ф series) — 6/10 kV switchgear. For designers: the typical solution "6(10) kV switching station on КРУ-Е cells (КМ-1Ф frame size)".

Figures (from the passports)

КРУ-Е-6/630 switchgear in the КМ-1Ф frame size, 2025

Set composition by variant: 03 — 10 pcs · 201 — 2 pcs · 601 — 2 pcs · 22 — 1 pc · 105 — 1 pc. Total 16.

Switchgear (from the passport's bill of supply): BB/VL-12-25/2000-У2 vacuum circuit breaker on a withdrawable truck; TCS2-12 current transformers, classes 0.5S FS4 / 0.5 FS4 / 10P10.

Why not everyone can do this

The КМ-1Ф frame size is a legacy of a series most manufacturers no longer build: it is easier to offer your own design and hand the client a building rebuild. We keep this frame size in production, so replacing an old switching station comes down to replacing cubicles rather than to civil works.

Photo report: from withdrawable trucks to the finished row

We'll build switchgear in your frame size

Send us the single-line diagram and the type of your existing cubicles — we'll size a set that drops into the old row. Withdrawable trucks, protection relays, busbars rated to your current.