A ShO-90 set: two incomer ratings and feeder panels in a single board

The task

A 0.4 kV board is rarely uniform. One site will have connections of very different weight side by side: a heavy incomer, a lighter one, and a dozen outgoing feeders each with its own rating. Making every panel identical "with margin" costs money and floor space; making every panel different costs lead time and complicates operation.

What was needed was a set in which different functions are covered by different panel types while staying within one construction: so that the board lines up as a continuous row, is serviced the same way throughout, and comes with a single body of documentation.

A separate requirement concerned metering: the incomers needed current transformers of an accuracy class fit for commercial settlement, not merely for panel instruments.

The solution

We built a set of eight ShO-90 panels in three type designs — all in a 2000 × 700 × 600 mm frame, each weighing no more than 120 kg.

• 1000 A incomer panels — 3 off (ShO 90-1113). An RE19-41 switch-disconnector rated 1000 A with an offset drive, and a VA-78 circuit breaker rated 1000 A with a breaking capacity of 70 kA. Metering is via three TSh-0.66-1 current transformers with a 1000/5 ratio.
• 2000 A incomer panels — 2 off (ShO 90-1114). The panel is rated for a main-circuit current of 2000 A; switching is by an RE19-43 disconnector and a VA79E-2000 circuit breaker rated 1600 A with an electronic trip unit and a breaking capacity of 80 kA. The T-0.66-2 current transformers with a 2000/5 ratio are built with a copper busbar.
• 1250 A feeder panels — 3 off (ShO 90-1406). Protection of the outgoing feeders is built on fuses: two RPS-2 disconnectors rated 250 A and two RPS-4 rated 400 A, served by six PN22 fuses rated 250 A and six rated 400 A. A solution with no semiconductor electronics: it clears fast, is restored by replacing the fuse link, and needs no settings.

Class 0.5S metering. The current transformers on both incomer types are accuracy class 0.5S — the class used for revenue metering of electricity, not just for panel instrument readings. In other words the board was built from the outset so that its data can be used in settlement for energy consumed.

One frame size across all three types. Despite different ratings and different internals, all eight panels share the same 2000 × 700 × 600 mm dimensions. On site they line up in a continuous, even row, they are serviced from the front in the same way, and spares and documentation do not fragment by type.

Degree of protection. The panels are IP00 from the installation side and IP20 from the front — staff are protected against contact with live parts from the face of the board, and the board itself is intended for installation in an electrical room.

Factory documentation. Each of the eight panels carries its own passport with a serial number and the order code (173889–173896). The warranty period is 3 years and the design service life to write-off is 25 years.

The series product card: ShO-90 panels for currents up to 4000 A. For design engineers: the standard solution "ShO-90 for a package substation". A related case: ShO-90 rated 2000 A with withdrawable breakers.

Figures (from the passports)

Photo report: the ShO-90 set in production

We will build a board to your diagram

Need a 0.4 kV board built to your single-line diagram? Send us the diagram or a completed questionnaire and our engineer will price the panel schedule, the ratings and the lead time. Preliminary quotation within 24 working hours.