Project Scope:
Supply and installation of a 33/11kV step-down substation package designed to serve 10 community distribution networks in Nigeria's Delta region, ensuring reliable power delivery under demanding operational conditions.
Core Solution:
Main Step-Down Transformers
Configuration: 2 units (redundant design)
Rating: Custom capacity (e.g., 2×7.5 MVA) to support total community load with future growth margin.
Voltage: 33 (±2×2.5%) / 11 kV | Vector Group: Dyn11
Cooling: ONAN/ONAF | Impedance: ~8–10%
Features: Sealed tank, corrosion-protected, integrated monitoring sensors.
Switchgear & Distribution
33kV Side: RMU or AIS panels for dual incomer + transformer feeders.
11kV Side: Modular switchgear with 12+ feeder panels (10 for communities + spares). Bus-section tie allows N-1 operation.
Protection: Microprocessor-based relays per feeder (overcurrent, earth fault).
Community Connection Points
Each community fed via a dedicated 11kV feeder.
At each community entrance: 11/0.433kV distribution transformer (e.g., 500kVA) and LV distribution board.
Key Adaptations for Nigeria:
Climate Resilience: IP54+ enclosures, C4/C5 anti-corrosion coating, designed for high humidity, dust, and ambient temperatures up to 45°C.
Grid Stability: On-load tap changer (OLTC) or wide-range off-load taps on main transformers to compensate for 33kV voltage fluctuations.
Lightning & Surge Protection: Heavy-duty surge arresters at 33kV & 11kV, low-resistance grounding (<1Ω).
Expandability: Modular 11kV switchgear allows easy addition of future community feeders.
Smart Features:
Local/remote SCADA interface for load monitoring, fault indication, and remote control.
Transformer monitoring (temperature, oil level, gas detection) with alarm/trip outputs.
Pre-fabricated and pre-tested substation modules to reduce on-site installation time.
Benefits for Client:
Reliability: N-1 redundancy ensures continuous supply to communities.
Future-Proof: Scalable design supports gradual community rollout and load growth.
Low Maintenance: Robust, climate-adapted equipment reduces downtime and servicing needs.
Compliance: Meets IEC standards and Nigerian utility grid codes.
Certification & Standards:
IEC 60076, IEC 62271, Nigerian Electricity Management Services Agency (NEMSA) requirements. Documentation includes test reports and local-language manuals.
