Marine System Solutions

ZTT provides comprehensive marine system solutions tailored for power transmission, communication networks, offshore oil & gas platforms, and offshore wind energy. With industry-leading technologies, robust engineering capabilities, and a strong track record in global deployments, we connect continents, energize industries, and enable a more sustainable and connected world beneath the waves.

Industry Overview

Offshore Wind Transmission Solutions

ZTT empowers offshore wind farms with comprehensive transmission systems for both inter-array and export power. We enable the reliable flow of renewable energy from sea to shore.

Industry Challenges

Rapid Technological Evolution

Offshore wind projects are moving toward higher capacities, deeper waters, and longer export distances. Cable systems must support higher voltages, larger conductors, and more complex installation conditions.

EPCI Capability and Schedule Pressure

Developers increasingly prefer suppliers with integrated Engineering, Procurement, Construction, and Installation capabilities. Tight project schedules and weather-dependent offshore operations intensify execution risks.

ESG and Environmental Compliance

Offshore wind projects are closely scrutinized for environmental impact, carbon footprint, and sustainability performance. Compliance with international ESG standards and transparent reporting has become a prerequisite for market access.

Our Solution

ZTT delivers integrated offshore wind solutions tailored to complex marine environments. Its capabilities span system design, a complete range of submarine cables and accessories—including bend restrictors and joint boxes—and offshore construction using its own marine engineering assets, covering cable laying and burial as well as wind-turbine lifting and installation.

66kV/132kV Wet-Design Inter-array Cable

A lead-free, lightweight cable designed to connect wind turbines. It significantly reduces weight and costs while maintaining high electrical performance in “wet” environments.

220kV/500kV HVDC/HVAC Export Cable

High-capacity transmission lines designed to deliver bulk power from offshore substations to the mainland grid, featuring robust armoring for long-distance reliability.

Value Contained

Enhanced ROI

Optimized cable layouts and high-voltage ratings (up to 500kV) reduce electrical losses, increasing the overall return on investment for wind farms.

Future-Ready Scalability

Supports the next generation of 15MW+ mega-turbines with advanced 66kV/132kV inter-array solutions.

Sustainable Infrastructure

Directly enables the large-scale integration of clean energy into the mainland grid, supporting global carbon neutrality goals.

Successful Cases

China - Yangjiang Sanshan Island ±500kV Project

End User: China Southern Power Grid

Contract Period: Apr. 2025 – Ongoing

Cable Type: HVDC ±500 kV

Transmission Capacity: 2.043 GW

Length: 116.5 km

China - Yangjiang Fanshi II 500 kV EPCI Project

End User: CGN

Contract Period: Mar. 2025 – Sep. 2025

Cable Type: HVAC 500 kV, 3*800mm2

Transmission Capacity: 1000 MW

Length: 92 km

China - Honghai Bay VI 500 kV Project

End User: Shenzhen Energy

Contract Period: Jun. 2025 – Ongoing

Cable Type: HVAC 500 kV

Transmission Capacity: 500 MW

Length: 94 km

Poland - Baltica 2 Project

End User: Ørsted A/S and PGE Poland JV

Contract Period: 2023 – 2026

Cable Type: HVAC 275 kV

Wind Farm Capacity: 1.5 GW in total, 375 MW per circuit

Total Cable Length: 158 km

Germany - OST-6-1 EPCI Project

End User: 50Hertz Offshore GmbH

Contract Period: 2023 – 2027

Cable Type: HVAC 220 kV

Transmission Capacity: 900 MW

Cable Length: 80.5 km

Vietnam – Vinh Long 128 MW Wind Farm Project

End User: REE Energy
Contract Period: Apr. 2026 – Sep. 2026
Cable Type: 22kV 3*95/240/500+2*48FO，35kV 3*95/150/240+2*48FO
Cable Length: 48.756 km
Transmission Capacity: 128 MW

Germany – TenneT Hohe See – BorWin Offshore Wind 155 kV Submarine Composite Cable EPCI Project

End User: TenneT
Contract Period: Jan. 2017 – Nov. 2019
EPC Contractor: ZTT
Subcontractor: Van Oord & EDS
Cable Type: 155 kV, 3*630mm2+2*24
Transmission Capacity: 497 MW
Total Cable Length: 27 km

China – Rudong H6 H10 Wind Field ±400 kV HVDC Submarine Cable EPCI Project

End User: Sanxia New Energy Nantong Co., Ltd.
Contract Period: Feb. 2020 – Dec.2020
Cable Type: HVDC 400 kV, 1*1600mm2
Transmission Capacity: 1100 MW
Total Cable Length: 99.1 km*2

Germany – TenneT Gode Wind 3 155 kV Submarine Power Cable EPCI Project

End User: REE Energy
Contract Period: Apr. 2026 – Sep. 2026
Cable Type: 22kV 3*95/240/500+2*48FO，35kV 3*95/150/240+2*48FO
Cable Length: 48.756 km
Transmission Capacity: 128 MW

Successful Cases

China - Yangjiang Sanshan Island ±500kV Project

End User: China Southern Power Grid

Contract Period: Apr. 2025 – Ongoing

Cable Type: HVDC ±500 kV

Transmission Capacity: 2.043 GW

Length: 116.5 km

China - Yangjiang Fanshi II 500 kV EPCI Project

End User: CGN

Contract Period: Mar. 2025 – Sep. 2025

Cable Type: HVAC 500 kV, 3*800mm2

Transmission Capacity: 1000 MW

Length: 92 km

China - Honghai Bay VI 500 kV Project

End User: Shenzhen Energy

Contract Period: Jun. 2025 – Ongoing

Cable Type: HVAC 500 kV

Transmission Capacity: 500 MW

Length: 94 km

Poland - Baltica 2 Project

End User: Ørsted A/S and PGE Poland JV

Contract Period: 2023 – 2026

Cable Type: HVAC 275 kV

Wind Farm Capacity: 1.5 GW in total, 375 MW per circuit

Total Cable Length: 158 km

Germany - OST-6-1 EPCI Project

End User: 50Hertz Offshore GmbH

Contract Period: 2023 – 2027

Cable Type: HVAC 220 kV

Transmission Capacity: 900 MW

Cable Length: 80.5 km

Vietnam – Vinh Long 128 MW Wind Farm Project

End User: REE Energy
Contract Period: Apr. 2026 - Sep. 2026
Cable Type: 22kV 3*95/240/500+2*48FO，35kV 3*95/150/240+2*48FO
Cable Length: 48.756 km
Transmission Capacity:  128 MW

Germany – TenneT Gode Wind 3 155 kV Submarine Power Cable EPCI Project

End User: TenneT
Contract Period: Sep. 2020 - Jul.2023
Cable Type: 155 kV, 3*1200mm² + 2*24
Transmission Capacity: 242 MW
Total Cable Length:  19.674 km

China – Rudong H6 H10 Wind Field ±400 kV HVDC Submarine Cable EPCI Project

End User: Sanxia New Energy Nantong Co., Ltd.
Contract Period: Feb. 2020 - Dec.2020
Cable Type: HVDC 400 kV, 1*1600mm² 
Transmission Capacity: 1100 MW
Total Cable Length: 99.1 km*2

Germany – TenneT Hohe See – BorWin Offshore Wind 155 kV Submarine Composite Cable EPCI Project

End User: TenneT
Contract Period: Jan. 2017 - Nov. 2019
EPC Contractor: ZTT
Subcontractor: Van Oord & EDS
Cable Type: 155 kV, 3*630mm²+2*24
Transmission Capacity: 497 MW
Total Cable Length: 27 km

Marine System Solutions

Industry Overview

Offshore Wind Transmission Solutions

Industry Challenges

ZHONGTIAN 31

ZHONGTIAN 39

Lan Hai Ling Hang

AC Submarine Power Cables

DC Submarine Power Cables

Offshore Engineering Accessory

Offshore Engineering Accessory

Offshore Engineering Accessory

Our Solution

66kV/132kV Wet-Design Inter-array Cable

220kV/500kV HVDC/HVAC Export Cable

Value Contained

Enhanced ROI

Future-Ready Scalability

Sustainable Infrastructure

Successful Cases

China - Yangjiang Sanshan Island ±500kV Project

China - Yangjiang Fanshi II 500 kV EPCI Project

China - Honghai Bay VI 500 kV Project

Poland - Baltica 2 Project

Germany - OST-6-1 EPCI Project

Vietnam – Vinh Long 128 MW Wind Farm Project

Germany – TenneT Hohe See – BorWin Offshore Wind 155 kV Submarine Composite Cable EPCI Project

China – Rudong H6 H10 Wind Field ±400 kV HVDC Submarine Cable EPCI Project

Germany – TenneT Gode Wind 3 155 kV Submarine Power Cable EPCI Project

Successful Cases

China - Yangjiang Sanshan Island ±500kV Project

China - Yangjiang Fanshi II 500 kV EPCI Project

China - Honghai Bay VI 500 kV Project

Poland - Baltica 2 Project

Germany - OST-6-1 EPCI Project

Vietnam – Vinh Long 128 MW Wind Farm Project

Germany – TenneT Gode Wind 3 155 kV Submarine Power Cable EPCI Project

China – Rudong H6 H10 Wind Field ±400 kV HVDC Submarine Cable EPCI Project

Germany – TenneT Hohe See – BorWin Offshore Wind 155 kV Submarine Composite Cable EPCI Project