Multi-Objective Control Algorithm for Small Hydro and SPV Generation-Based Dual Mode Reconfigurable System

Abstract

This paper proposes a small hydro (ac) and solar photo-voltaic (SPV) generation (dc)-based dual mode multi-functional reconfigurable system. The small hydro system is connected to the point of common coupling (PCC) directly. The SPV system is connected to ac side (PCC) through a boost converter and a voltage source converter (VSC). A storage system is integrated across dc link of VSC through a bidirectional converter to balance the generation and the loads in an islanded mode. The distinguished feature of proposed system is that it operates either in grid connected mode or an islanded mode depending on grid availability. It supplies uninterruptable power to emergency loads. An important aspect of control strategy is that it automatically synchronizes the system to the grid when the grid is available in an islanded mode. It also disconnects the system from the grid when a fault occurs on the grid feeder in grid connected mode. In an islanded mode, it regulates voltage and frequency of hydro generator across PCC. In grid connected mode, it regulates the current fed by VSC. It also improves the power quality of the hydro generator and the grid by elimination of current harmonics, load balancing, and compensation of reactive power under nonlinear loads. The performance of proposed system is found satisfactory in transient modes and in dynamic conditions. The interruption time in the load end voltage and resynchronization time are well within an IEEE 1547 standard. The total harmonic distortion of grid current, hydro generator current and load voltage is also well under IEEE 519 standard even at nonlinear loads.