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substation · indoor distribution · low voltage

Indoor 11 kV to 400 V distribution substation single line diagram

This substation single line diagram shows an indoor 11 kV to 400Y/230 V distribution substation for a building. An 11 kV utility cable enters an SF6 ring main unit load-break switch, then passes through a transformer fuse to a 630 kVA cast-resin transformer. A 1000 A low-voltage air circuit breaker supplies the main distribution bus.

Tipo Schema unifilareStandard IEEE Std 315 + ANSI device numberingMotore schematex-sldAggiornato 22/09/2026
Indoor 11 kV/400 V substation
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La richiesta

“Draw an indoor 11 kV to 400 V distribution substation single line diagram with an SF6 RMU load-break switch, 63 A transformer fuse, 630 kVA cast-resin transformer, 1000 A LV air circuit breaker, and lighting, power, and HVAC feeders.”

Prova alloraAdd a second 630 kVA transformer and bus tie.Change the HVAC feeder to 500 A.
Cosa contiene questo disegno

Leggi le decisioni che ne stanno alla base.

01Indoor MV isolation

An SF6 RMU load-break switch receives the 11 kV cable supply.

02Transformer branch

A 63 A fuse protects the 630 kVA transformer primary.

03Dry transformer

Cast-resin construction suits an indoor equipment room.

04LV main protection

A 1000 A ACB feeds the 400Y/230 V distribution bus.

05Building feeders

Lighting, power, and HVAC loads are independently protected.

Use this for a building-scale indoor substation concept. Room ventilation, fire strategy, protection settings, and local MV standards must be verified.

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FAQ

Domande frequenti

Why use a cast-resin transformer indoors?

It avoids liquid dielectric fluid and is commonly selected for indoor applications.

What is the RMU switch used for?

It provides compact medium-voltage switching and isolation at the cable incomer.

Does a transformer fuse replace all protection?

No. Final protection design must coordinate MV fuses, LV breakers, and upstream utility devices.