Modeling and validation of the Flex Power Grid Laboratory

Modeling and validation of the Flex Power Grid Laboratory

Tourgoutian, B.

Popov, M. (mentor)
De Jong, E. (mentor)
Vaessen, P. (mentor)

Electrical Engineering, Mathematics and Computer Science

Electrical Power Engineering

Sustainable Energy Technology

2013-12-19

The increasing penetration of dispersed generation changes the way in which distribution grids are comprised. The impact of the introduction of grid-connected distributed energy resources is expected to receive growing attention in the near future. Power electronic equipment is now indispensable part of the electricity generation and distribution; however apart from its benefits, it may affect the grid adversely as well. Power quality and reliability are the challenges that grid operators face, because of fluctuating loads and penetration of decentralized electricity generation. The use of power electronics has the potential to enhance the energy management and enables grid operators to make smarter use of their grid. The Flex Power Grid Lab (FPGL) in Arnhem provides an ideal testing and research environment for advanced power electronics. Businesses and universities can make use of this excellent facility to study how locally generated energy, such as wind turbines, solar cells, CHP plants, can be safely integrated into the grid. The lab facility is capable of generating both static and dynamic voltage phenomena and creating test conditions, such as harmonic distortion, voltage dips, frequency and voltage fluctuations. As a result, equipment involved in decentralized power generation can be tested under “bad grid” conditions, prior to its actual connection to it. The intent of this Master Thesis is to model the FPGL using certain software in order to ultimately be able to predict the performance of the lab. MATLAB/Simulink environment is used for the purposes of the project. The modeling starts from the 50kV substation in Kattenberg. A transformer steps down the voltage to 10.5kV. FPGL along with other labs of DNV KEMA is connected to the 10.5kV bus-bar, which is located in the Business Park, Arnhem. Two three-phase and three single-phase temperature dependent transformer models have been developed. Special attention is paid to the modeling of the grid-connected 4Q, 1MVA, AC/DC – DC/AC converter, which consists of two three-level neutral-point clamped PWM converters. Different control scheme is applied to each of these converters. The grid-side converter is controlled in the rotational reference frame, using proportional-integral (PI) controllers with ultimate goal to keep the DC-link voltage stable. Park transformation (dq0) is necessary to transfer the system to the rotational frame. In contrast, the load-side converter is controlled in the stationary reference frame using proportional-resonant controllers (PR). This innovative control strategy stabilizes the plant by state-feedback, while ten available resonant controllers ensure zero steady-state error for up to nine harmonics. Both control schemes are developed in the z-domain to take into account the effect of the Digital Signal Processor. Ultimately, the model is validated through several lab tests.

power quality
three-level converter
resonant controller
vector control
dq transformation
simulink
validation

http://resolver.tudelft.nl/uuid:4cbffe27-272c-4b4b-8527-5285515b13bd

Student theses

master thesis

(c) 2013 Tourgoutian, B.