Integrated 161/11kV Substation Works for Power Plants

ZHM is pleased to announce the successful completion of the detailed engineering, fabrication, supply, installation, and commissioning services for three critical 161kV/11kV substations in Ghana, West Africa.This project encompasses the Chirano, Wassa, and Edikan substations, serving as the vital grid interconnection points for major gas-fired power generation facilities.

This project marks a significant milestone in ZHM's international expansion, demonstrating our capability to deliver complex Electrical Power Infrastructure under stringent international standards.

Project Scope and Technical Overview

The project involved the complete Erection and Commissioning of 161kV Air Insulated Switchgear (AIS) substations. ZHM's scope covered the entire value chain, ensuring seamless integration from factory to site.

1. High Voltage (161kV) Primary Equipment Installation

The heart of each substation is the 161kV AIS (Air Insulated Switchgear) yard. ZHM managed the intricate installation of the following key components:

▶Circuit Breakers: Installation of Live Tank SF6 Circuit Breakers (Model LW36-161) rated at 170kV, 3150A, and 40kA short-circuit withstand. Our team meticulously handled the Hydraulic-Spring Operating Mechanism calibration and SF6 Gas Handling to ensure arc quenching efficiency.

▶Switchgear Assembly: Precise erection of Double-Column Horizontal Disconnectors (GW16-161DW) and Earth Switches (JW-161), ensuring proper phasing and mechanical interlocking.

▶Instrument Transformers: Installation of Capacitive Voltage Transformers (CVT) (TYD161/√3) and High-Voltage Current Transformers (CT) with multi-core configurations (0.2S, 5P20) for accurate metering and protection.

▶Overvoltage Protection: Integration of Metal Oxide Surge Arresters (Y10W1-144) on both line and transformer sides to protect equipment from lightning and switching surges.

2. Medium Voltage (11kV) and Transformer Interface

To step down the generator output (11.5kV) to the grid voltage, ZHM executed the following works:

▶Main Transformer Interface: Although the 66/80MVA Power Transformers were Owner-Furnished (TBEA), ZHM was responsible for the critical Transformer Installation, including positioning, oil filling supervision, and bushing connections. We ensured the Vector Group (YNd11) alignment and OLTC mechanism integration.

▶MV Switchgear: Installation of 11kV Indoor Switchgear and associated circuit breakers, forming the generator bus connection.

▶Conductor Systems: Fabrication and erection of Aluminum Tubular Busbars (Φ130mm) and AAAC Conductors (630mm²) for overhead connections, ensuring optimal current carrying capacity and corona control.

3. Secondary System Integration and Control

A modern substation relies heavily on its nervous system. ZHM delivered a comprehensive Digital Substation solution:

▶Protection & Control: Implementation of a full Substation Automation System (SAS) featuring IEC 61850 communication protocols. We installed CSC-series Protection Relays (CSC-103, CSC-101, CSC-150, CSC-326) for line, transformer, and busbar protection.

▶SCADA and Telecontrol: Deployment of PCS-9700 workstations and servers, enabling remote monitoring and control. The integration included PLC (Power Line Carrier) systems using ABB ETL 600 transceivers for reliable communication with the national grid (GRIDCo).
▶Auxiliary Systems: Complete installation of DC Power Systems (125V VRLA Batteries with chargers) and 415V LV Distribution Boards to ensure uninterrupted power for critical controls.

4. Civil, Structural, and Safety Infrastructure

Beyond electrical equipment, ZHM engineered the physical backbone of the substations:

▶Steel Structures: Detailed design, Hot-Dip Galvanizing (HDG) treatment, and erection of Gantry Frames, equipment support structures, and Lightning Arrestor Masts. All steelwork complied with GB 50017 and ISO 1461 standards for corrosion protection.

▶Grounding and Lightning Protection: Construction of a low-resistance Grounding Grid using exothermic welding (Cadweld), targeting a resistance of ≤ 0.5 Ω. This was supplemented by a comprehensive Lightning Protection System covering all critical assets.
▶Safety and Security: Installation of CCTV Surveillance Systems (Hikvision), Fire Detection and Suppression Systems (including FM-200 cabinets), and HVAC systems to maintain optimal operating temperatures in the control rooms.

Execution Methodology and Quality Assurance

The project was executed under a rigorous Quality Management Plan (QMS) compliant with ISO 9001:2015. Key aspects of our methodology included:

▶Factory Acceptance Testing (FAT): Comprehensive testing of all panels, relays, and switchgear at the manufacturer's premises before shipment.

▶Logistics Management: Coordination of sea freight to Tema Port, Ghana, and inland transportation of heavy equipment (including transformers weighing up to 120 tons) to the remote sites in the Western Region.
▶Site Commissioning: Execution of Site Acceptance Tests (SAT), including Primary/Secondary Injection Testing, Insulation Resistance (IR) Testing, Contact Resistance Measurement, and Polarity Checks.
▶Energization: Successful First Energization and completion of the 72-Hour Continuous Operation Test, marking the final handover to the client.

Conclusion

The successful delivery of the Chirano, Wassa, and Edikan substations underscores ZHM Metal Engineering's expertise in Turnkey Substation Solutions. By adhering to IEC, IEEE, and Chinese National Standards (GB), ZHM has proven its capability to execute complex power transmission projects in challenging international environments.

These substations are now operational, facilitating the stable export of power from independent power producers (IPPs) into the Ghanaian national grid.

1 3D BIM Model Wassa 161kV Substations

2 Chirano Substation Gantry Frame Inlet Outlet Conduct

3 Wassa Substation Gantry Truss PT Lighting Arrester

4 Chirano Power Plant Substation Bird View

5 Edican Sub Station Interconnection Existing 161kV

7 Bus bar Bay Gantry Frameworks

8 Pipe type Bus Bar Factory Production Inspection

9 Tube Bus Bar Container Loadings Delivery

10 Wassa Substation Layout Plan Drawing

11 Prefabricated Busbar Junction Box Air Box

12 Transformer 3P Oil Immersed Outdoor Step Up Onan Onaf

13 LV Tubular Bus Bar From Power Plant Substation

14 HV Tubular Bus Bar Supporting Insulators

15 Prefabricated High Voltage 161kV Air Insulated Swithgear AIS

16 Telecommunication Equipment PLC System

17 Illumination Lighting System Distribution Board

18 Substation BIM Modeling Wassa LV Power Cable Edican Busbar

19 Substation Prefabricated Steel Structures Container Loading

20 Wassa Chirano Substation Foundation Preparation

21 Gantry Frame Insulator Hardwares Erection

22 Busbar Support Structures Gantry Frames

23 Disconnector Earth Swith SGS Inspection

24 Lighting Surging Arrester Installation

25 Substation Grounding System Cad welding Material Preparation

26 Lighting Prection Tower Polyn Pole System SPD

27 Communication Equipment ABB FOX615 CPU Power STM GE Electric Panels

28 5000A Prefabricated Containerized Breakers

29 Secondary System UPS DC Panel DCS Cabinets

30 Conduct Cable Delivery

31 Insulators Clamps Hardwares Delivery Container Loading

32 Substation Steel Structures Container Loadings

Why ZHM Huawu Metal 161kV Substation Constructions ?

Reliable and Customized Designs	Cutting Edge Designing Process	Free Online Price System	Easy Bolt-by-number Assembly
Over Two Decades of Experience	Value For Money	Unmatched in Quality and Craftmanship	Excellent Customer Service

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HOW CAN WE HELP YOU?

ZHM’s world-class team — together with our raw material suppliers and subcontractors — works to solve your most challenging design, engineering, farbrication or construction issues.

Contact ZHM by telephone at +86 135-8815-1981 (wechat and whatsapp) or send us your questions via email to info@zhmsteelworks.com