Design reliable DC power systems for substations, power plants, and industrial facilities — including battery bank sizing, cable sizing, voltage drop calculations, and comprehensive load listing.
DC systems are the backbone of protection, control, and emergency power in substations, power plants, and industrial facilities. When the AC grid fails, your DC system must still operate protection relays, trip circuit breakers, power control systems, and emergency lighting. Our DC calculation service ensures your battery-backed DC system can handle every load — steady-state and transient — for the full duration of an outage.
DC system design involves a comprehensive analysis of all DC loads, battery capacity, charger ratings, and cable sizing to ensure reliable operation under all conditions:
Identify and categorise all DC consumers: protection relays, trip coils, control circuits, communication equipment, emergency lighting, and instrumentation.
Calculate the minimum Ah capacity to supply all loads for the required autonomy period (typically 1–4 hours for substations, longer for power plants).
Verify that voltage at the furthest load point remains within acceptable limits (typically 90–110% of nominal) under both charging and battery discharge modes.
Size battery chargers to supply normal DC loads while simultaneously recharging the battery within specified timeframes.
DC system failures during AC outages are a leading cause of protection system unavailability:
Our DC calculation methodology follows a rigorous, step-by-step engineering process:
Compile a comprehensive load register for every DC consumer, classified by operation mode (continuous, emergency, transient) and duty cycle.
Apply IEEE 485 or IEC 62484 methodology to calculate minimum battery capacity, accounting for end-of-life capacity, temperature derating, and voltage profiles.
Size DC cables based on current-carrying capacity and voltage drop constraints (max 3% from battery to furthest load per standards).
Evaluate battery performance under transient inrush loads (breaker tripping, motor loading) to ensure voltage dips remain within acceptable limits.
Our comprehensive DC system design includes:
We've designed DC systems for substations from 33 kV to 400 kV, power plants, and industrial facilities across the Middle East, Africa, and Asia. Our team understands the critical nature of DC systems and delivers calculations that ensure your protection and control systems will operate flawlessly when the AC grid fails.
Our team of power systems engineers is ready to provide expert guidance, detailed studies, and robust solutions tailored to your specific requirements.