Harmonic Distortion Analysis of a Micro Gas Turbine Interconnected to the Electricity Grid.

Abstract

Micro gas turbines have opened new opportunities for integrated energy systems using thermally activated technologies for waste heat recovery, improved overall efficiency and reduced emissions in commercial buildings and other small-scale polygeneration applications. However some issues are still unclear, such as the legal and technical issues regarding the electric grid interconnection. In this paper both issues will be addressed from the point of view of the electric system protections and the power quality supply with respect to harmonic distortion. The objective is to provide data and analyse the harmonic distortion of a low-pressure natural gas micro gas turbine of 28 kWe interconnected to the grid. Additionally the main interconnection requirements and protection systems will be described. The studied micro gas turbine cogeneration system is located in the Technological Innovation Centre CREVER at the University Rovira i Virgili in Tarragona (Spain). The results obtained show that the harmonic distortion is clearly below the limits recommended by the existing international standards. Also the already built-in microturbine interconnection protections are enough to assure the correct operation and safety of the micro turbine system and the external grid. However increased communications and automation will be required to manage large amounts of distributed micro gas turbines generation systems connected to the grid.