GIC observations and studies in the Hydro-Quebec power system

Presents a method to use linear analysis to capture the frequency coupling of nonlinear and time-varying components. System stability is analyzed by connecting the harmonic transfer functions of the different component models. This facilitates an object-oriented approach to modeling, which supports reuse of models. An analysis of the complete railway system is, of course, difficult. Several locomotives can be moving along the power distribution line at the same time, and depending on the distance between them, the interaction changes. The power consumption also changes, depending on operating modes. During normal operation, energy is consumed from the network, but as modern locomotives use electrical braking, the power flow changes direction during deceleration, and energy is delivered back to the grid. The inverter trains are not passive systems. The converters are controlled with only limited system knowledge (local measurements of currents and voltages), making analysis and control design an even bigger challenge.

Out of control because of harmonics-an analysis of the harmonic response of an inverter locomotive

This paper presents three harmonic simulation test systems. The purpose is to demonstrate guidelines for the preparation and analysis of harmonic problems through case studies and simulation examples. The systems can also be used as benchmark systems for the development of new harmonic simulation methods and for the evaluation of existing harmonic analysis software.

Test systems for harmonics modeling and simulation

This paper proposes a new method to model the harmonic generating characteristics of AC/DC converters. The model transforms the time domain nonlinear characteristic of the converter into a frequency domain linear admittance matrix. The matrix represents the coupling among the converter AC side harmonic voltages and currents accurately and it does not vary with the harmonic conditions of the system. The proposed model opens up a new way to conduct harmonic power flow studies. This paper presents the theoretical foundation and analytical derivation of the admittance model for both single-phase and three-phase bridge rectifiers. Potential applications of the model are discussed.

http://www.ece.ualberta.ca/~apic/papers/Power_Quality/PQ-2007-%20Harmonic%20Matrix%20Model%20for%20Converter.pdf

A Harmonically Coupled Admittance Matrix Model for AC/DC Converters

This paper is a review of the different single and three-phase harmonic load flow formulations of the bibliography. It presents the data, unknowns, and equations of these formulations in balanced network consideration. The influence of the main harmonic load flow hypothesis (harmonic interaction and fundamental power consumption consideration) in the final load flow results is studied in an example.

Review of harmonic load flow formulations

Circulation of direct current in transformer windings can cause significant transformer saturation and harmonic generation. This problem may be experienced by static VAr compensators with an anti-parallel thyristor arrangement. This paper presents a technique to analyze the harmonic distortions caused by transformer saturation with direct current offset. The technique is used to investigate the harmonic generation from the transformer of a static VAr compensator to be installed in the BC Hydro system. >

J.H. Sawada

Papers

Harmonics from SVC transformer saturation with direct current offset