Secondary Design Interface Engineer – Electrical Substations

About the role

The Secondary Design Interface Engineer will support the design and implementation of secondary systems in high‑voltage electrical substations. Working within Mott MacDonald’s Energy – Transmission & Distribution division, you will collaborate with primary designers, project managers and clients to deliver reliable, compliant solutions for renewable power, grid connections and other critical infrastructure.

Key responsibilities

• Coordinate secondary system design with primary design engineers and project stakeholders.
• Prepare and review technical specifications, drawings, interface circuit diagrams, wiring diagrams, cable schedules and room layouts.
• Perform calculations for battery sizing, voltage drop and cable sizing.
• Ensure designs meet industry standards and client requirements for protection, control and communication systems.
• Support integration of SCADA and other monitoring systems within HV substations.

Required profile

• Degree in Electrical Engineering or related discipline.
• Experience with secondary design of HV substations (132 kV, 275 kV, 400 kV) in AIS or GIS environments.
• Ability to work collaboratively across multidisciplinary teams.

Required skills

• HV substation secondary design
• Protection and control system design
• SCADA system integration
• Circuit diagram and wiring diagram preparation
• Cable scheduling and sizing
• Voltage drop and battery sizing calculations
• Familiarity with AIS & GIS equipment at 132 kV, 275 kV, 400 kV