In November 2005, the GCC Interconnection Authority awarded a contract to connect the Saudi Arabian grid to the grids of Bahrain, Qatar and Kuwait. The interconnection is a key part of the GCC interconnection project and is notably the first HVDC link in the Middle East.
In November 2005, the Gulf Cooperation Council Interconnection Authority(GCCIA) awarded Areva T&D two contracts to enable the connection and management of the grids of Saudi Arabia, Bahrain, Qatar and Kuwait. The two contracts are part of the first phase of a larger project to connect the grids of the Gulf States of Saudi Arabia, Bahrain, Kuwait, Qatar, UAE and Oman.
The Chandrapur back-to-back HVDC converter station for the interconnection of the western and southern electrical regions of the Indian grid system. Areva will supply similar converters for the GCC project
Notably, under the first agreement Areva T&D will supply what will be the first HVDC station in the Middle East. The 1800 MW HVDC station will allow the exchange of power between Saudi Arabia’s grid, which operates at 380 kV and 60 Hz, and the power network connecting Bahrain, Kuwait and Qatar, which operates at 400 kV and 50 Hz. The second contract will see Areva T&D design and build the entire automation system for the GCC network.
The GCC interconnection project began in 1990 with a study which recommended an AC connection of the 50 Hz systems of Kuwait, Bahrain, Qatar, the UAE and Oman with a back-to-back HVDC connection to the 60 Hz Saudi Arabian system.
Electricity demand in GCC countries is expected to grow from 32 747 MW to 94 000 MW over the next 25 years (see Table 1). The study showed that interconnection of the grids would have a number of benefits. It would:
à¢€¢ Reduce the amount of capacity needed in each system since it would allow the sharing of reserves
à¢€¢ Allow the sharing of spinning reserve so that each system could carry less spinning reserve
à¢€¢Allow the exchange of energy between systems resulting in lower operating costs
à¢€¢ Increase overall system reliability since systems could supply emergency power to each other.
Approximate route and layout of the GCC Grid Interconnection
The study recommended that the project be carried out in three phases. Phase 1 would see the interconnection of the northern systems (Kuwait, Saudi Arabia, Bahrain and Qatar) in 2008. In Phase 2 the southern systems (UAE and Oman) would be interconnected to form the UAE national grid and the Oman northern grid. Under Phase 3, the northern and southern grids would be connected in 2010.
Areva T&D’s contract is part of Phase 1 of the project. The main elements of Phase 1 are:
à¢€¢ A double circuit 400 kV, 50 Hz line from Al Zour (Kuwait) to Ghunan (Saudi Arabia) with an intermediate connection to Al Fadhili (Saudi Arabia) and associated substations.
à¢€¢ A back-to-back HVDC interconnection to the Saudi Arabian 380 kV, 60 Hz system at Al Fadhili.
à¢€¢ A 400 kV double circuit comprising overhead lines and submarine link from Ghunan to Al Jasra in Bahrain and associated substations.
The converter valve consists of a large number of thyristors connected in series
à¢€¢ A 400 kV double circuit line from Ghunan to Salwa (Saudi Arabia) and associated substations.
à¢€¢ A double circuit 400 kV line from Salwa to Doha South (Qatar) and associated substations.
à¢€¢ A control centre located at Ghunan.
The cost of Phase 1 of the project, based on tenders received in 2005, is $1.1 billion. It was agreed that the costs would be shared between the countries in proportion to the reserve capacity savings.
Phase 1 of the project began in early 2004 with a feasibility study to assess the technical and economic viability of the interconnection. Financing between the various governments was agreed in May 2004 and tender documents were issued to pre-qualified contractors for the different work packages. In November 2005, the GCCIA awarded 13 EPC contracts to local and international companies and one project management contract to Canadian company SNC Lavalin for the supervision of the project.
Areva T&D’s contracts for the HVDC station and automation system are valued at a total of g194 million. Commenting on the contract award, Marco Graziano, Areva T&D’s executive vice president of sales said: “The main factor that contributed to our winning the contract was our flexibility in being able to adapt our offer to meet the customer’s requirements. We have the right technical solutions.”
Under the contract, Areva T&D will deliver three converter stations (3×600 MW), thyristor valves, 375 MVA converter transformers, harmonic filters, and 400 kV circuit breakers.
With the Saudi grid operating at 60 Hz and the Bahrain, Kuwait and Qatar network operating at 50 Hz grid, HVDC was the best solution for connecting the two systems. It is ideal for connecting separate networks since it obviates the need for network synchronization. HVDC also has a number of advantages over HVAC. The technology is particularly suited to transmitting power over long distances because losses are low. It is also useful when trying to avoid faults from propagating through interconnected networks by providing isolation.
At the heart of the HVDC station is the converter valve, consisting of a large number of thyristors connected in series. The valve is normally suspended from the roof of the valve hall for protection against seismic events, and the ‘switching’ occurs in a controlled manner in order to transmit the required current and power. The controlling of the valves will be carried out by the Series V control system – Areva’s latest digital duplicated HVDC controls.
The ‘switching’ of the valves leads to harmonics being generated, which are in turn prevented from entering the respective AC networks by the harmonic filters. In addition, these filters play a part in the overall strategy of reactive power control for the station.
The power flowing across the HVDC link and the entire system will be controlled by the grid automation system. Areva T&D will deliver the telecommunications infrastructure, protection relays, substation automation, and the network management for the control centre for the entire network. The telecommunications infrastructure comprises a high-speed fibre backbone spread across 800 km, which will transmit key information to the control centre.
The control centre will guarantee the efficiency and the safety of the power grid while enabling the recording and billing of energy transactions between the different countries.
Areva T&D was awarded the HVDC contract on November 24, 2005, with a completion time of 37 months. Equipment will be sourced from Areva units located around the world. The core engineering competence will be based in Stafford, UK, and St. Priest in France.
Harmonic filters play a part in reactive power control for the station
Areva T&D’s part of the project is still in the early design phase. Shipping main equipment will be during the third quarter of the project. Mobilization at site will take place in the first quarter of the project with civil works, scheduled to commence after the preliminary site work has been completed.
Installation and commissioning will begin at the end of the third quarter of the project. The system will then be completed and energized by January 2009.
Commenting on the overall award of the contract, Graziano commented: “Overall it has been a very positive experience. There has been support at the GCC level with little interference from the utilities. The project has been discussed for a long time but once they agreed, they really walked their talk on the schedules.”