Projects / Utilities

Transmission substation, DC auxiliary system

In a substation the DC system is what allows protection to operate when the AC side is already in trouble. It is specified around the worst-case duty cycle, not around average load.

Short answer

DC auxiliary supply for protection and control, specified to the substation's tripping and closing duty profile.

At a glance

Location: Kosova.

Sector: TransmissionDuty: Protection and control DCStandards: IEEE 485 sizing methodScope: Design, supply, commissioning

The brief

Provide a DC auxiliary system for protection relays, control, and switchgear operation, sized to the substation duty cycle including tripping and closing currents.

What we delivered

A duty-cycle calculation first, then equipment selected against it. Nothing was ordered before the load profile was agreed in writing.

—Duty-cycle sizing per the IEEE 485 method with margin for ageing and temperature
—Chargers with monitoring and alarm contacts wired to SCADA
—Battery racking, DC distribution, and labelling to plant standard
—Full commissioning records handed over as part of the asset file

Outcome

A DC system with a traceable design basis, so future load additions can be checked against the original calculation instead of guessed.

Have a similar site?

Send us the load profile and the constraint. We will tell you what the work involves before anyone quotes hardware.