HMF-MAK Training – Secondary Interlocking design (review)

Objectives
• Understand the purpose of interlocking in substation safety.
• Learn to review interlocking schemes for correctness and safety.
• Identify different types of interlocking (mechanical, electrical, software-based).

Key Topics
• Safety principles: Prevention of inadvertent disconnection or earthing of live circuits.
• Common interlocking schemes: Busbar earth switch, feeder earth switch, transformer HV/LV.
• Hard-wired interlocking vs. logic within Bay Controllers (IEC 61850 GOOSE).
• Role of key interlocks and trapped-key systems.
• Reviewing interlocking logic diagrams and matrices.

course video

Practical Focus
• Case study review: Analyzing an incorrect interlock condition that could lead to a safety hazard.
• Exercise: Creating an interlock matrix for a double-busbar arrangement.

Suggested Diagrams
• Interlocking logic diagram for a transformer bay (HV side isolator/earth switch).
• A table showing the “permissive” conditions for operating a critical switch

Key Takeaways
• Competence in reviewing and validating substation interlocking schemes.
• Appreciation for the role of interlocks in personnel and equipment safety.

Standards & References
• IEC 61936-1 – Power Installations Exceeding 1 kV AC.
• National Grid / Transmission Company specific interlocking philosophies

Certification & Delivery
• Certificate of Completion awarded.
• Delivery Mode: Online (On-demand).
• Corporate and customized training available on request.