الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Offshore Wind Farm (OWF) has been gained a wide acceptance nowadays as it is deemed one of the extremely used renewable energy source owing to its wide utilization all over the world and the major unexploited wind energy as well as better wind circumstances. One of the main parts in this system is the controller itself, so the appropriate selection of effective controllers is considered important and necessary.
The significant problem facing the renewable resources and impedes their spread and widespread use of them to support the unified network is their control structure. This control structure is very complicated and consumes a long time. So, many researaches have been directed towards the new control algorithms and techniques to defind the main controllers parameters. Among the most important and most frequently used controllers in OWF connected to High Voltage Direct Current (HVDC) transmission systems and in almost of practical experiments and in industries applications are Proportional-Integral (PI) and Fuzzy Inference System (FIS) controllers. FIS is commonly utilised in inverter control stations in many applications due to its appropriate for use in a nonlinear system and involves no mathematical modelling. Thus, FIS is chosen to improve the performance of the converter/inverter stations in the studied model.
The main contribution of this thesis is to present an optimal design process for the controller’s parameters utilized in the voltage source converter (VSC) of OWF interconnecting with a HVDC transmission system by using a meta-heuristic algorithms for enhancing the performance of the system under study.
The proposed algorithms are used to design and tune the PI controllers’ parameters to improve the performance of overall system. It shall be mentioned that, these parameters are usually hard to obtain owing to the high level of embedded nonlinearity in such energy systems. The performance of such optimally designed PI controllers is presented during network disturbances dut to the transient conditions.
On the other hand and related to FIS controller, optimization technique can be used to fine tune the FIS controllers’ parameters (such as the scaling gain factors and the membership functions for each FIS input/output), to overcome the design constraints on FIS, to handle the complexity of the studied system, and finally to optimise the FIS behaviour.
The analytical and statistical solutions acquired from the offered algorithms are compared with other meta-heuristics approaches such as genetic algorithms to examine the efficiencies of the design parameters in case of symmetrical or asymmetrical faulty conditions happened at grid side. It is spotted that the offered algorithms have promising features and better-damped performance compared to genetic algorithm especially to fulfill the Fault Ride Through (FRT) capabilities of OWF connected with the grid via HVDC transmission system.
The new algorithms were extensively examined and tested using the MATLAB/Simulink simulation package and were confirmed to be reliable as demonstrated in the simulated results. With the proposed optimization algorithms, FRT capability of Permanent Magnet Synchronous Generator (PMSG) based Variable Speed Wind Turbine (VSWT) and connected with HVDC transmission can be improved.
For the sake of examining the realistic stability of the proposed algorithm, real wind speed pattern has been captured from Egypt wind farm at Zafarrana and is deemed in this study.