Design of northern electrical transmission network in west bank

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Rabei Hendyeh
Mohammed Burghal
Hamza Hinnawi
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Introduction: There is no generation in West Bank; electricity sector depends on the electrical power generated by IEC, which refuses most Palestinian requests to increase the supplied capacity. As a result West Bank cannot guarantee electrical energy supply forever, so Israel has another way to practice pressure on Palestinians.The cities of west bank is fed by several small connection points from IEC side distributed around main cities at 33 kV or fed directly from Israel at 161 kV likeTulkarm and Qalqilya or fed form near settlements for more than 125 SPS feeding 130 MVA especially for villages.Tulkarm and Qalqilya regions have 22KV systems, and the Northern electrical systems are operated at 33KV. The present grid suffers from fragmentation, high losses, low reliability, high energy prices, low maintenance, and disability to handle the future demand.In order to achieve electricity independency from IEC side the first step is build a unified transmission structure, then give chance for investments in generation sector.The importance of the project comes from:Reduce energy cost ($/kwh) which Facilitate investment and industrial and urban development.Reduce maintenance cost .Increase the expansion possibility.Reduce the installed capacity of the network due to diversity factor between cites.Encourage investments in generation sectors.Use other sources to satisfy the increasing demand. There is existing planes to create an unified Palestinian network in West Bank .One of them is put by PENRA (Palestinian energy and national recourses authority). The aim of this plan is to create a transmission sector its job is to buy electrical energy from different sources (like IEC, international connection or from generating sector which can be private sector ) and supply it to distribution companies to deliver it to consumers .By these plans there will be 4 connection points to this transmission company, 2 in the north and one in the middle and the last is in the south of West Bank.Another plan is put from NEDCO (northern electrical distribution company) .its aim is to connect the northern of West Bank at 33 KV level by developing the existing network and change all connection points from the IEC side to 2 BSP one is Sara near Nablus and the other is Al-Jalama near Jenin. Each has a capacity of 135 MW (3*45 MW)( 161/33 KV )  transformers .For future expansion a 4th 45 MW transformer will installed at Sara substation to increase its capacity to 180 MW. Moreover a 3rd substation will be established between Tulkarm and Qalqilya, as shown in the map next page. There is also tendency to establish a generation plant (Thermal one) at Jenin near Al-Jalama by a capacity of 200 MW by the year 2020. It will replaced instead of the IEC BSP of Al-Jalama, which in turn support the independency of electrical sector in Palestine. Our work:Our project was with cooperation with NEDCO (Northern Electrical Distribution Company). In it, we followed technical and economic issues to create a transmission network of Northern West Bank to achieve min. losses, reliability and efficiency of delivered power. Our project is a transmission network in the northern west bank, so we will use high voltage as unusually in our cities, such as 161 KV which are taken directly from IEC so that we can skip some of huge transformers in the network which are very costly.In our project we have two main connection points, the first one is Sara connection point and the second one is al Jalama and it is considered as swing bus. Both with maximum capacity of 135 MW.We started by collecting data from loads to distances between cities. These data was taken directly from NEDCO. By which we have 6 cities Nablus, Salfit, Tubas, Jenin, Tulkarm and finally Qalqilya. Nablus is at the center of the loads with maximum load of about 82 MW. That why we chose Sara as connection point near Nablus. Then we chose Al-Jalama near Jenin because it hase the second maximum load after Nablus.After that, we continued by estimating of power needed (real and reactive powers), calculating of voltage needed and power flow in the network and power factor correction because the PF shouldnt be less than 0.92 to avoid penalties from IEC side. After that we made several configurations from redial to ring ones. Then we selected elements like transmission lines, transformers and switch gears.As a next step, we made economic calculations depending on net annual present value to decide the cheapest design. Then we simulated it at several conditions (minimum load, maximum load, faults and expansion for future) at modified power analyzer program (ETAP) to show the realistic of our design. A load flow studies is important to determine the situation of the network in operation.The load study must be done in three conditions:Max. load stateMin. load state                        After fault stateIf the voltage of the busses were less the desired value it is necessary to follow the steps:                        Increasing the tap changing up to 12%.Adding capacitors at the busses.The losses percentage is determined by equation  . in transmission the losses should not be more than(2-3)%, and in our network the losses didn't exceed 1% The loads are supposed to be increased in future so a load forecasting study is necessary.The best scenario to achieve the future demand with minimum losses and minimum voltage drop is to create a new connection point between Tulkarm and Qalqilya. And it should be established before 2016.The age of our network must be at least 5 years, and to cover the gap of needed energy we made several scenarios to achieve best technical issues.This well integrated network will allow future connection to the rest of West Bank to create unified Palestinian transmission network and in turn allowing installing generation plants with it.A copy from these prohect will be delivered to NEDCO as cooperationn between them and our university. Futrure work: For future work it is recommended to design a protection system for optimum network, study and analyze either the new generation plant at Al-Jalama or the new connection point between Tulkarm and Qalqilya.