Electrical Power Engineering

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https://hdl.handle.net/20.500.11888/13968

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    A NEW METHOD FOR OPTIMALLY DESIGNING THE POWER DISTRIBUTION NETWORK OF GRID-CONNECTED PHOTOVOLTAIC POWER PLANT
    (An-Najah National University, 2024-02-11) Assi, Hiba Bashar
    Photovoltaic (PV) systems are attractive renewable energy source for rural electrification and distributed power generation. However, the capital cost of these systems as compared to non-renewable energy sources is still a challenging issue. Thus, many researchers have focused on enhancing the efficiency and the feasibility of photovoltaic systems. This research proposes an optimum methodology for designing the AC power distribution network for grid connected photovoltaic systems considering solar inverter size and location, as well as cable’s size and configuration. The main aim of the proposed method is to offer the shortest cables length and path; achieving a higher efficiency and feasibility in the overall assessment. The suggested approach follows a heuristic method, starting by generating numerous inverter combinations for analysis. For each combination, the total length of cables is calculated considering all feasible inverter locations, aided by Python code to ensure precision. Ultimately, the method identifies the optimal inverter location that results in the shortest cable lengths. A 900 kWp grid connected photovoltaic system is chosen as a case study in this research. Results show that a 23% reduction in total cable length as compared to the conventional approach is achieved by the proposed method. Meanwhile the proposed method offered a better configuration of required solar inverters (size and location). Such a method is very useful for designing photovoltaic system AC and DC distribution networks and exceed and the conventional and intuitive methods.
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    A PROPOSED METHOD FOR MITIGATION THE UNBALANCED CURRENTS IN POWER DISTRIBUTION NETWORK WITH PV SYSTEMS
    (An-Najah National University, 2025-04-23) Raed Aref Kmail, Ahmad
    This study aims to solve the problem of uneven electricity use in homes that share a three-phase power supply. This unevenness happens when too many houses rely heavily on just one or two of the three power lines, leading to wasted power, overloaded lines, voltage drops and even blackouts. The growing use of solar panels on homes makes this problem even worse since the amount of electricity they produce can fluctuate . To fix this, the project created a smart system that uses a microcontroller and WiFi technology to constantly monitor and adjust how electricity is distributed among the three power lines. It keeps track of how much power each house uses and how much solar energy is being produced, then automatically shifts houses between the lines to keep things balanced. Tests of this system show losses reduced from 138 kW to 9 kW—resulting in cost savings of $193.2, or $3.75 per house. The system achieved a simple payback period of less than one month. Furthermore, the lowest network voltage improved from 206 V under unbalanced conditions to 221 V after implementing the balancing solution. This study is important because it shows how to better manage modern power grids that include a lot of solar energy. By using this system, power companies can ensure a more stable and dependable electricity supply to homes while also supporting the use of renewable energy sources like solar power.
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    THE IMPACT OF DEMAND SIDE MANAGEMENT ON THE UTILIYU ACTIONS FOR IMPROVING THE OPERATION OF DISTRIBUTION SYSTEMS CONSISTING PV GENERATOR
    (An-najah national university, 2025-02-04) Hanhan, Malaka
    This thesis investigates the impact of demand-side management (DSM) strategies on utility actions for improving the operation of distribution systems with high photovoltaic (PV) penetration. A case study was conducted using OpenDSS software, applying the IEEE 30-bus test network. A 50 MW PV system was integrated into bus 21, demonstrating its ability to reduce total electrical losses in transmission lines from 9308.34 kW to 7742.83 kW. Meanwhile, the study examined the application of various DSM strategies to further enhance network performance after hosting the PV system. Direct Load Control (DLC) reduced network losses to 5365.5 kW, while the Time-of-Use (TOU) tariff strategy significantly reduced losses to 3736.9 kW. Additionally, the Conservation Voltage Reduction (CVR) strategy improved overall network voltage profiles, particularly decreasing the voltage at bus 21 from 1.0524 p.u. to 1.0442 p.u. and at bus 11 from 1.0819 p.u. to 1.0748 p.u. The hosting capacity analysis revealed that increasing PV penetration initially reduced electrical losses, with significant reductions observed at penetration levels of 15 MW, 30 MW, 50 MW, and 70 MW, corresponding to losses of approximately 9830 kW, 8000 kW, 7000 kW, and 5800 kW, respectively. However, beyond a hosting capacity of 70 MW, further increases in PV penetration led to a rise in losses, reaching 7900 kW at 150 MW and exceeding 12,200 kW at 200 MW. The use of DSM strategies effectively mitigated these losses even at higher penetration levels. For instance, DLC reduced losses to approximately 6000 kW, and TOU reduced them further to 5000 kW at a 200 MW PV hosting capacity. These findings highlight the critical role of DSM strategies in enhancing the operational efficiency and reliability of distribution systems with high PV integration
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    THE IMPACTS AND MITIGATION STRATEGIES OF REVERSE POWER FLOW IN DISTRIBUTION ELECTRICAL NETWORK WITH HIGH PENETRATION OF RENEWABLE ENERGY SYSTEMS
    (An-Najah National University, 2024-10-15) Khalefeh, Mai
    The increasing penetration of renewable energy systems (RES), particularly distributed generation (DG) such as solar photovoltaic (PV), has transformed modern power distribution networks. While this technology offers environmental and economic benefits, it also introduces significant technical challenges. One of the most critical issues is reverse power flow (RPF), which occurs when the generation from distributed sources exceeds local demand, causing power to flow back toward the electrical distribution network. This thesis addresses the impacts of reverse power flow due to high penetration in the electrical distribution network; A detailed analysis is conducted to assess how RPF affects voltage profiles and transformer losses. Through ETAP simulated an electrical distribution with 33 buses , 14 step-down transformers with 10KV /0.38KV rating and 19 loads connected to the buses. The network simulation was done by adding a solar PV energy system and addressing the benefits, then increasing the number of solar PV arrays connected to buses to reach PV penetration at various levels of 20%,40%,60%, in PV penetration no existing to reverse power flow, the buses’ voltages rising to an acceptable levels and this effect improves the electrical network and reduces the transformers losses ,but if any solar PV arrays connected to a bus and generated power exceeds the demand load that connected to that bus a reverse power flows towards the distribution transformer causing losses and rising in voltage. The network was simulated by reducing the load demand to reach PV penetration levels of 109% , and190% ,the reverse power flow amounts was increased with the increase in PV penetration to high levels .and this case occurred when the solar PV system generated power in peak times while the load demand is light .high level of PV penetration produced many impacts as voltage rising issue and transformers losses issue .various mitigation strategies were proposed as BESS (battery energy storage system ), load shifting ,and zero export devices and smart inverters. Assessment was done for each mitigation strategy and choosing between these solutions depends on the specific grid conditions, regulatory framework, and available financial resources.
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    ELECTRICAL NETWORK RECONFIGURATION FOR IMPROVING THE RELIABILITY OF DISTRIBUTION SYSTEM CONSISTING OF RENEWABLE ENERGY SOURCES
    (An-Najah National University, 2024-10-10) Thiab, Tahreer
    This thesis evaluates the impact of network reconfiguration on improving the reliability of an electrical network with high PV penetration. The reliability of the electrical network depends on the failure rates of the components installed within it. However, for loads in the network, the failure rate and outage duration can be affected by voltage conditions. In some cases, improving the voltage can reduce the failure rate of loads, but an increase in PV penetration can lead to voltage rise, which may result in a higher failure rate. This thesis discusses how variations in PV penetration impact the reliability indices of the network and explores how reconfiguration of the network can improve its reliability. The case study uses the modified IEEE 33-bus network with a PV penetration level of 70% of the installed electrical loads. Without a PV system, the network experiences voltage drops in loads far from the connection point, leading to a high failure rate due to low voltage. However, with high PV penetration, voltage rise also affects reliability. Reconfiguring the network by connecting additional buses improves voltage conditions in both scenarios, leading to enhanced reliability indices. Without PV, the network's reliability indices are as follows: Average Interruption Rate is 83.847 failures per year, and Average Outage Duration is 1.81 hours. The indices are SAIDI: 151.694, SAIFI: 83.847, EENS: 730.407, and CAIDI: 1.809 hours. With 100% PV penetration but without reconfiguration, the Average Interruption Rate is 54.81 failures per year, and the Average Outage Duration is 1.67 hours. The indices are SAIDI: 91.6206, SAIFI: 54.8103, EENS: 441.153, CAIDI: 1.672 hours. When reconfiguration is added, the network's reliability indices improve: the Average Interruption Rate is 56.7532 failures per year, and the Average Outage Duration is 1.65 hours. The indices are SAIDI: 95.6504, SAIFI: 56.7532, EENS: 460.557, and CAIDI: 1.685 hours. The results, obtained using ETAP software, show that while adding PV reduces losses, it may decrease the reliability of the network if reconfiguration is not implemented. However, with reconfiguration, network reliability is enhanced.