Industries
Power distribution for industrial facilities
Transformers, switchgear and substations for plants and process sites, from the urgent replacement of a failed unit to new capacity for an expansion.
The equipment chain
- 01GridThe supply at the plant boundary. Its fault level sets what every breaker downstream must interrupt, and the connection agreement caps the demand.
- 02MV switchgearThe plant incomer and its feeders. The largest motors are often fed straight from this board at medium voltage, through vacuum contactors or circuit breakers.
- 03TransformerSized as often by the start of the largest motor as by the running load. Its impedance sets how far the voltage dips while that motor starts.
- 04LV boardFeeds the motor control centres and process panels, and must withstand the fault current the transformer's rating and impedance allow.
- 05Process loadMotors, drives, heaters and controls. Drives add harmonic currents that heat the transformer beyond what their kilowatt figure suggests.
A plant's loads shape its supply. Large motors draw several times their rated current while they start, and the voltage dip is what the rest of the plant notices. Variable speed drives change that picture and add harmonic currents of their own.
When a transformer or breaker fails, the nameplate and the existing drawings define what the replacement has to match. You then decide what to accept: a new unit to the same rating and footprint, or a surplus or refurbished one that may shorten the wait. We offer that route when you agree to it, with the unit's condition documented.
What decides the ratings
Motor starting and harmonic loads decide the transformer more often than the steady load does. When a large motor starts direct on line from a small transformer, the voltage dip sets the rating. Soft starters and drives change that calculation.
For a replacement, the existing installation decides. The voltage pair, the vector group, the impedance if units run in parallel, the footprint and the cable connections all have to match, or be changed on purpose.
What to settle early
| Consideration | Why it matters here |
|---|---|
| Motor starting | Sets the rating and the impedance more often than the running load |
| Drives and harmonics | Affect transformer losses, heating and specification |
| Parallel operation | Requires matching vector group, ratio and impedance |
| Replacement urgency | Surplus or refurbished units may shorten the outage, where acceptable |
| Environment | Dust, heat and corrosive atmospheres affect enclosure and cooling |
| Plant expansions | A compact substation can add capacity without new building work |
Equipment for this application
What we need to quote
- For a replacement: nameplate details and photographs of the failed unit
- Rating, voltage pair and vector group
- Largest motor rating and starting method
- Drive and other converter loads
- Whether surplus or refurbished units are acceptable
- How urgently the equipment is needed on site
Building or expanding a facility?
Send the whole equipment schedule as one project, each item with its own requirements.