Browsing by Subject "Voltage"
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Item ANALYSIS OF KATHMANDU GRID DIVISION AND INTREGATED NEPAL POWER SYSTEM WITH OPTIMAL PLACEMENT AND SIZING OF CAPACITOR(Pulchowk Campus, 2021-03) THAKURI, MANISHA SHAHIThe lower voltage of transmission system in the Integrated National Power System (INPS) has been a major concern for the Nepal Electricity Authority (NEA). The lower transmission voltage induces the lower voltage in the sub-coordinates (sub-transmission and distribution system) causing reduced voltage and overall higher system loss. The loss in the transmission system has increased from 4.35% to 4.51% in previous year. A total of 97.5km 132kV line and 182km of 220kV line in the FY2076/77 along with 72.5 MVAR of capacitor bank has been augmented in last couple of years. Though such appreciable effort, considering the system enhancement, has been done in the improvement of the transmission system, the problem is still existing. The main reasons for the existing problem can be: the higher increase in demand than the supporting infrastructures. So, this research aims to study the existing system during the system peak and perform an impact analysis in the system with the addition of the optimum sized capacitors in the optimum location for the voltage improvement and overall loss reduction. The study also emphasizes the economic aspect with the addition of the capacitors analyzing the various economic parameters. The sub-objective of the study also includes analysis of the loading status of the transmission lines in the Kathmandu valley. For the acknowledgement of system, the Electrical Transient Analyzer Program (ETAP) has been used as simulation tool. Adaptive Newton-Raphson has been used for the load flow and the Optimum Capacitor Placement (OCP) module inbuilt with Genetic Algorithm (GA) to determine the optimum placement and sizing of the capacitor banks. Moreover, a techno-economic analysis has been performed for the determination of the most suitable voltage level for the capacitor placement. From the analysis it has been found that the system suffers a transmission line loss of 4.16% in the system peak. Also, 6 optimum substations with the total reactive power of 80 MVAR needs to be added in the system for the energy savings of about 16.02 GWh per annum. The economic analysis shows that the implementation of the study has an is economically sustainable with the payback period of 5.97 years and 19.69 % Internal Rate of Return when the capacitors are placed at the most financially suitable voltage level i.e., 11kV determined from the results obtained.Item Optimal Network Reconfiguration and Distributed Generation Integration for Power Loss Minimization and Voltage Profile Enhancement in Radial Distribution System(I.O.E. Pulchowk Campus, 2022-09) Manandhar, NareshNetwork Reconfiguration with Distributed Generation (DG) integration can significantly reduce power loss and improve the system voltage. This thesis explores the approach for reduction in power loss and improvement in system voltage through a combination of network reconfiguration and DG installation in radial distribution systems. Initially, the approach was verified in a typical 33 and 69 Test Bus system in MATLAB using the Backward/Forward Propagation Load Flow approach. Voltage Stability Index (VSI) technique has been applied to determine the most sensitive bus to locate for DG integration. Artificial Bee Colony (ABC) algorithm was used to determine the optimal solution. Six scenarios for different combinations of system reconfiguration and DG installation were analyzed by using NEA 63-Bus real distribution network of the Nepal Electricity Authority (NEA), Kirtipur Distribution Center. The simulated results were compared with the base case scenario and were validated with results from the previous studies for DGs injecting active power only. Among them, Scenario VI (simultaneous network reconfiguration and DG integration) gave the best result for power loss reduction and voltage profile improvement. The results obtained in this study show that, for DGs generating active power only, the percentage reduction in active or real power has been improved by 72.19%, 83.52%, and 57.69% for the IEEE 33, IEEE 69, and NEA 63-Bus system respectively. Similarly, for DGs generating both real and reactive power, the power loss has been reduced by 91.61%, 96.53%, and 90.54% for the IEEE 33,Item Optimal Sizing and Placement of FCL for Restoring Recloser-Fuse Coordination in DG-Integrated Distribution System Using MOPSO Algorithm(Pulchowk Campus, 2021-02) Khadka, PurushottamWith the demand for a more reliable power supply and the decentralization of the power system, there is a high penetration level of distributed generators in the distribution system. Some merits of DG integration are power loss reduction, voltage profile improvement, reliability improvement, backup supply and so on. The high penetration level of DG in the distribution system has led to the large contribution of fault current by the DG units to the fault location. The problem with the fault current provided by the DG unit is that the proper coordination between protective devices such as recloser-fuse coordination is disturbed. To restore the protection coordination between recloser and fuse, the fault current needs to be reduced. The fault current can be reduced by using a fault current limiter. With the optimal planning of Fault Current Limiter (FCL), the protection-coordination between recloser-fuse can not only be maintained but also the cost associated with FCL installation can be reduced. This thesis is focused on minimizing the size and the number of FCL for maintaining recloser fuse coordination. Moreover, the FCL should also reduce the voltage sag in the distribution system during the fault condition. Because of the flow of large fault current, there is a large voltage drop along the distribution line which results in low bus voltage. Since FCL reduces the fault current, the optimal sizing and placement of FCL should also minimize the voltage sag. Thus, in this thesis, the four objective functions:- the reduction of the fault current through the protective device to restore recloser fuse coordination, the reduction of the size of FCL, the reduction of the number of FCL, and the reduction of voltage sag during fault conditions are considered. The optimization problem is solved by using the Multiple Objective Particle Swarm Optimization Method (MOPSO) which uses non dominated solutions found in the external repository to guide the flight of the particle in the search space. Unlike PSO which gives a single solution to the optimization problem, MOPSO provides a set of non-dominated solutions which are called Pareto optimal solutions. Out of many non-dominated solutions, the best solution for the optimization problem is the solution with the minimum number of FCL along with a minimum size that can restore the recloser fuse coordination as well as maintain the voltage sag during the fault condition. The optimal calculation of size, number and placement of FCL are considered for two test systems: Canadian Bench Mark Test System, and IEEE 69 bus test system. The iv optimization problem using MOPSO has been solved in MATLAB and the results are simulated and verified in ETAP software. For the Canadian Bench Mark Test System, only two FCLs with a total size of 3.093 pu was found necessary. The current minimization and voltage minimization indexes were 8.867 pu and 0.530 pu respectively. Similarly, for IEEE 69 bus system, 12 FCLs with a total size of 1.978 pu was found necessary. The current minimization and voltage minimization indexes were 28.276 pu and 0.492 pu respectively.Item Potential determination, performance and voltage profile analysis of grid connected roof-top solar PV at Bishnumati Distribution Feeder(Pulchowk Campus, 2022-03) Poudel, Padam RajThis thesis presents the solar roof-top photo-voltaic generation capacity at Bishnumati feeder of Balaju Distribution Control System (DCS) with its performance and voltage profile analysis during grid connection by considering eleven potential commercial and non-commercial buildings. The Building Foot-Print Area (BFA) obtained is 8915.13 m2 and the actual photo-voltaic area (PVA) is 4190.11 m2, which is used to install the solar module in the roof of the selected buildings. PVsyst is used for performance analysis, the energy generated by solar array (E_array) and energy supplied to the grid (E_grid) is 1018.319 MWh and 982.039 MWh per year respectively. The performance ratio over the year is 0.74. The average capacity factor of overall installation is obtained as 17 %. ETAP is used for feeder modeling and load flow analysis. Form load flow analysis the minimum grid voltage before solar PV injection is 10.32 kV at a nominal bus voltage of 11 kV. After injection of solar PV into the grid, the minimum bus voltage is improved to 10.53 kV.Item Techno-Financial Analysis of Optimal Capacitor Placement and Design, Selection and Injection of Distributed Energy Resources (DERs) in Jomsom Distribution Feeder(Pulchowk Campus, 2021-09) Niraula, DayasagarOne of the challenging tasks of the concerned distribution authorities is to transmit the quality of power with proper reliability to the consumers. The aim of the authorities is to transmit maximum power with minimum losses and maintain a good voltage profile so that the power factor is improved and hence power transfer capability increases. Although it is almost impossible to reduce the losses to zero, power losses can be minimized. One of the ways to minimize the losses and improve the voltage profile and voltage stability is by supplying reactive power into the system, which is possibly by means of various compensating techniques such as injection of capacitor banks or Distributed Energy Resources (DERs) into the system. Usually, the voltage sags along the Radial Distribution System and is maximum at the sending end of the Distribution System and minimum at the ends of the feeder. This voltage can be improved through the injection of compensating devices or Distributed Energy Resources (DERs) taking into account both the technical and financial aspects into consideration. This research employs the Standard IEEE 10 bus system as the test bus for validation, which is carried out by comparing the results with the published research works. Then, the same methodology is applied for Jomsom Distribution Feeder for performance improvement of the distribution system through Optimal Capacitor Placement and grid impact analysis of injection of Grid Connected Solar and Wind Power Plant in the system. The bus voltages at each node, power losses, voltage regulation, voltage profile, and total annual costs are compared for both the cases, i.e. before and after compensation through capacitor banks and injection of DERs. The total savings in annual cost is computed in both these cases. Power losses is reduced by 18.5 % and 14.5 % for Standard IEEE 10 bus system and Jomsom Distribution Feeder respectively due to Optimal Placement of Capacitor banks in the feeder. Voltage Regulation is improved from 16.25 % to 11.63 % for Standard IEEE 10 bus system and from 18.24 % to 5.54 % for Jomsom Distribution Feeder after Optimal Capacitor Placement. There is saving in $ 23,955.084 annually for Standard IEEE 10 bus system and $3,806 annually for Jomsom Distribution System, Kobang due to Optimal Capacitor Placement in Distribution System. Further injection of DERs in the distribution system feeder improves the voltage profile and helps in power loss reduction.