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A robust sequential primal-dual linear programming formulation for reactive power optimization is developed and discussed in this paper. The algorithm has the characteristic that no approximations or complicate control logic are required in the basic Sequential Linear Programming (SLP) formulation as used by other SLP algorithms reported in the literature. Transmission loss minimization is used as the primary objective. A secondary feasibility improvement objective is used which results in better feasible solution in comparison with the loss minimization objective especially when the initial base case has over voltages. Modification in the proposed method to obtain the limited amount and limited movement of controller solution for real time application is also presented. The algorithm has been tested on Ward and Hale 6-Bus system.

Vertical axis wind turbine (VAWT) can be operated in any direction of wind speed, but it has low rotation. To improve the performance of VAWT in which low rotation, this paper presents a simple control strategy of VAWT using a DC-DC boost converter to tap constant voltage in a standalone application. The main objective of this research is to maintain a constant output voltage of converter despite variation input voltage affected by variable wind speed. A simple proportional-integral (PI) controller has been used for a DC-DC boost converter and tested in MATLAB-Simulink environment, with the closed-loop system of the converter maintain constant output voltage although the wind speed is kept changing. The PI controller obtains the feedback from the output voltage of the boost converter to produce the correct pulse width modulation (PWM) duty cycle and trigger the metal oxide semiconductor field effect transistor (MOSFET) following the reference voltage of the turbine. This system has suppressed the value of overshoot and increased the efficiency of wind turbines as 34 %.

Pico hydro or a small scale hydroelectric power plant is used as the rotating energy of the generator. Pico hydro is a hydroelectric power plant that has a power of less than 5 kW. Technically, Pico hydro has three main components namely water, turbine and generator. Turbine type propeller reaction has a special profile that causes a decrease in water pressure during the blades. This pressure difference exerts force on the blade so that the runner (rotating part of the turbine) can rotate. Permanent magnets are used to produce magnetic flux. Permanent magnets used are rare-eatrhrod magnet material, neodymium-iron-boron NdFeB with N35 type. The planned generator released is 36.85 V, 500 rpm, 50 hz. This designed water turbine has four blades which cannot change its angle. As for the measurement results produce a voltage of 35.1 V with a manufacturing efficiency of 95 %. Charging the battery voltage must be more than 12 V, therefore the generator must be turned at least 200 rpm with a voltage of 14 V to be used for charging batteries.