| Summary: | 碩士 === 國立臺灣科技大學 === 電機工程系 === 98 === Development of central protection unit for smart-grid protection system needs fast and accurate protection coordination. This thesis presents programmatic coordinating protection devices using optimization technique both for radial type and ring type of distribution systems. Traditionally, the relay engineer used to spend much time on calculation and trial-error the time-current graphics in order to coordinate the overcurrent relays. Many information and lots of calculations had to be done, during the process lots of setting had to be changed; changes in the settings of one relay could change others relays setting. Nowadays, the relays should respond to the changing system conditions such as new distributed generation (DG) connection to the main grid. Traditional protection relay coordination is hard to respond to this condition particularly for large network power distribution systems. Optimization technique can help to solve this coordination issue.
To reach an optimal coordination, linear programming (LP) technique and a metaheuristic algorithm called particle swarm optimizer (PSO) algorithms are introduced and implemented. Linear programming with simplex method is applied to initialize the setting parameter of overcurrent relay. PSO is applied to minimize the operating times of the relay. The objective function is to find the minimum total of operating time primary relays. The additional effect of different types of distributed generation such as synchronous DG and induction DG on fault current is also discussed; various schemes of operation mode are also covered. To test the proposed method, program based on Borland C++ 2007 and MATLAB on simple distribution network is introduced. Ultimately, the parameter settings of protection devices are generated and satisfy the constraint to reach the optimal coordination.
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