Protection of modern power grids with multiple renewable sources and power converters

Abstract

The most important concern of all power grids is their protection systems. Traditionally, they have been met by mechanical relays and circuit breakers. However, in modern grids, where multiple renewable sources and power electronic converters are widely used, new means of implementing grid protection has become possible.

This report describes the design of a DC-DC converter for the terminal users of the microgrid which can convert the initial voltage into any voltage level automatically and the design of a protection system of the grid.

In this project, a Cuk DC-DC converter was chosen and a simple Buck-Boost converter was also used as a comparative test. By comparing the performance of the two different converters, some advantages and disadvantages of each type have come up. And this report provides some recommendation in this research field based on the results.

Besides, different control techniques have been used for these two different converters. Voltage-mode control was used for the Buck-Boost converter and it has shown good performance. The Cuk converter took on a double-loop control technique which also delivered quite satisfying results. And a comparison between different control techniques has been made to form a constructive conclusion and recommendation.