The Seven Countries Interconnection Project (SCIP), which will interconnect the grids of Libya, Egypt, Jordan, Syria, Iraq, Turkey and Lebanon, was launched at the beginning of the last decade. The interconnection will allow for cost reduction, increased reliability, secure operation of networks and economies of scale, with cost savings from the construction of larger generating units with higher efficiency. The future plan will include enlarging the seven countries power grid to link it with Europe via Turkey in the north and Morocco in the west.
The Seven Countries Interconnection Project will connect in stages the grid systems of Libya, Egypt, Jordan, Syria, Jordan, Iraq, Turkey and Lebanon.
SCIP is a major project and it has involved, and will involve,many steps on the long road to completion. The first stage was the interconnection of Libya and Egypt. Both grids were connected in 1998 through a 225 kV double circuit overhead line, which links the Tobruk substation in Libya with the Saloum substation in Egypt. The tie line was designed to carry around 600 MW, but due to technical constraints, the maximum power exchange between both parties is limited to 180 MW.
The interconnection of the electrical networks of Egypt and Jordan marks the first stage of the interconnection between Egypt, Jordan, Syria, Iraq and Turkey. This interconnection was implemented in 1998 through a 400 kV submarine cable. It is 13.5 km in length and crosses the Aqaba Gulf at a depth of 850 metres, connecting the Taba substation 500/400 kV in Egypt with the Aqaba substation 400/132 kV in Jordan. The designed AC operational capacity of the cable was 550 MW, however, it is designed for future DC operation, which should increase the capacity to 1200 MW.
The interconnection between Jordan and Syria was implemented in January, 2001 through a 400 kV single circuit overhead line, and links the Der-Ali 400/230 kV substation in Syria with the Amman North 400/132 kV substation in Jordan. This tie line which is 147 km long was designed to carry 700 MW.
Syria and Lebanon were already interconnected at the 230 kV level, and are due to be linked by a 400 kV double circuit overhead line. This new line, 44 km in length, will be commissioned in two phases. The first phase allows a transfer of 300 MW, while the second is expected to be commissioned in 2010, which will lead to a 600 MW increase in capacity.
The interconnection between Syria and Iraq was planned to be in operation in 2002 through a single AC circuit 400 kV overhead line. with a total length 165 km. It is to connect the Der-Azzour substation in Syria with the Al-Qaem substation in Iraq. However, due to the current situation in Iraq the completion time of the project is uncertain.
The Turkish power system will be interconnected with the Syrian through a single AC circuit 400kV overhead line. The construction work was completed in 2003, butwhen it will come online is unclear.
Committees leading the way
SCIP’s management comprises three joint committees – the steering committee (SC), the planning committee (PC) and thegeneral and bilateral operational committee (GBOC).
The members of the SC include high-level managers from companies and utilities, and it is their task to set the policies, strategies and general rules to improve and develop the interconnection. The PC exchanges planning policies, skills and experiences, and will eventually work to reduce investments in the introduction of new generation capacities. They plan to get the most economical dispatch from all generation units. The GBOC’s main task is to set the operational instructions and procedures, as well as continuously coordinate and update the operational data of the interconnection.
The tie line projects between the members of the seven countries of SCIP and the development of a market through the exchange of energy across the tie lines has required three special agreements. These include a general trading agreement, a bilateral construction agreement, and an interconnection agreement. These ensure that expenses, benefits and commercial transactions are the same for all related parties.
Table 1 illustrates the total energy exchange through the Libya-Egypt, Egypt-Jordan and Jordan-Syria tie lines up until June last year. While, the energy tariff between Jordan and Egypt and between Jordan and Syria with regard to the bilateral power purchase agreements is based on three tariff periods, during the working days of the week and Fridays during the summer and winter periods (Table 2), as well as published international fuel prices.
Security of the systems
The operation and control of the interconnected power systems is quite complex because this large system has to operate in synchronizm despite different organizations in each control system being responsible for different portions of the grid.
Real-time control of the interconnected system is required to respond to the actual demand of electricity and to any unforeseen circumstances. As electrical utilities in each interconnected system involves a complex network of generators, transmission lines, distribution feeders, and loads, the control center is considered the operation’s headquarters for each utility. Since the generation and the delivery of electrical energy are controlled from this center, it is referred to as the “energy control center” or “energy management system”.
The primary control reserve must also be sized correctly to avoid the activation of the first step of the under-frequency, load-shedding scheme in case of an outage of the largest generation block.
Conditions of interconnection
Each partner of the interconnected system must satisfy certain conditions in its own supply zone. Firstly, each company must help to compensate for a disturbance in the grid in proportion to its share of the total power output of the interconnected network at the time of the disturbance. Secondly, the generation/consumption balance must be permanently ensured by each partner by putting into operation its own power stations, as well as import contracts and if necessary by activating load-shedding.
In the Libya-Egypt-Jordan-Syria interconnection system, each control area must contribute to the correction of the disturbance during the first 30 seconds in accordance with its respective contribution coefficient to primary control. The interconnection tie lines of this system are equipped with coordinated protective relays to achieve the security of the interconnected system during stress conditions, which permits the opening of the tie line between both grids to avoid large frequency deviations or voltage collapse.
Egypt-Jordan and Syria-Jordan tie lines are equipped with over current relays and under frequency relays set on 49 Hz, and with a special protection scheme (SPS), which disconnects large substations(300-400 MW) in the Jordanian system when the power flow through the Egypt-Jordan tie line reaches 550 MVA.
After the black out of the Jordanian system in August 2004 because of the Aqaba Power station tripping (650 MW), it was followed by the tripping of the Egypt-Jordan tie line. In turn this led to a decline in frequency to a value less than 49 Hz, causing the tripping of the Syria-Jordan tie line. However, the Syria-Jordan tie line enabled a quick restoration of the Jordanian system, and all consumers were restored within a two hour period.
Technical co-operation between Libya, Egypt, Jordan, Syria and Lebanon is expected to continue to support the internal networks of the interconnected countries, in order to increase the capacity of exchanged electricity between these countries up to the capacity of the Egypt-Jordan interconnection cable, which is approximately to 550 MW.
Co-operation between Egypt, Libya, Tunisia, Algeria, and Morocco will also continue to look at the possibility of increasing the interconnection voltage between these countries to 400-500 kV. The aim is to increase the capacity transferred to those countries, which is currently limited to the existing interconnection voltage of 220 kV.
Technical co-operation among the interconnected countries in the east and west Arab region is also expected to continue, particularly in the area of the measurement and testing of the Libya-Tunisia interconnection, as a step towards complete interconnection between the countries extending from Syria in the east to Morocco in the west. Furthermore, a co-ordinating monitoring centre is expected to be established similar to that of the European grid system.
It is hoped that SCIP will yield great technical and economical benefits for all interconnected parties by minimizing the spinning reserve and increasing the reliability of supply and stability margin of the interconnected grid.