Home About Services RelaNex Academy Why Us Contact Get in Touch →
ENRU

ATS Circuit Design

Automatic Transfer Switch schemes decide what happens to your critical loads in the seconds after a supply is lost. We design them three ways — as hardwired logic, configured inside numerical relays, or on dedicated PLC control — and recommend the one that matches your availability requirement and maintenance capability, not the one that suits a particular supplier.

What this covers

  • Transfer scheme selection — open, closed and fast transfer, with the trade-offs made explicit for your load types.
  • Implementation route — hardwired relay logic, logic internal to numerical relays, or PLC-based control.
  • Supply supervision — undervoltage, phase loss, phase sequence and synchronism check criteria.
  • Motor load considerations — residual voltage decay and re-acceleration behaviour on transfer.
  • Interlocking — preventing parallel operation of sources that must not be paralleled.
  • Architecture — conventional hardwired signalling or IEC 61850 GOOSE, including transfer timing implications.

What you receive

  • ATS scheme description and sequence of operation
  • Control and interlocking schematics
  • Relay or PLC configuration and logic documentation
  • Timing analysis for the selected transfer method
  • Functional test procedure for commissioning

Standards and references

Design references IEC 61850 where a station bus is used, IEC 60255 for relay functions, and the IEEE C37 series for transfer scheme practice.

Related services

Relay Logic Design

Custom protection and control logic for numerical relays, across hardwired and IEC 61850 schemes.

Relay Setting Calculations

Setting and coordination calculations that keep fault clearance selective, fast and reliable.

Protection Philosophy Development

The document that sets protection principles, coordination strategy and design criteria for the whole project.

All RelaNex Group services →

Need ats circuit design scoped?

Work directly with the engineers doing the analysis — clear scoping from the first conversation.

Get in Touch