Jon Berge

Determination of maximum PV solar system connectivity in a utility distribution feeder

This paper presents a study for determining the maximum amount of PV solar generation that can be connected in a 27.6 kV feeder of a distribution utility - London Hydro. Various factors such as steady state voltage rise, Temporary Over Voltage (TOV), short circuit current and harmonic contributions, that could potentially constrain DG connectivity are investigated. Load flow studies with PSS/E and electromagnetic transient simulation studies with EMTDC/PSCAD software are utilized for performing the above investigations. It is shown that harmonic amplification due to network resonance could potentially be the limiting factor for PV solar connectivity in this distribution feeder. This paper also makes a case that the conventional Connection Impact Assessment (CIA) studies for DG connections need to be made broader to include such harmonic aspects.

Laboratory validation of the relationship between Geomagnetically Induced Current (GIC) and transformer absorbed reactive power

This paper presents the theory and simulation work to establish a relationship between Geomagnetically Induced Current (GIC) flowing through a transformers windings and the reactive power absorbed by that transformers core. This relationship is determined in laboratory for various levels of GICs injected under different loading conditions of a transformer. This obtained relationship validates the results obtained through electromagnetic transients simulation using PSCAD/EMTDC and also correlates well with actual field data. This study is one of the first laboratory simulation studies of the effect of GIC, reported in literature.

A software simulator for Geomagnetically Induced Currents in electrical power systems

This paper describes the development and testing of a software simulator to calculate the flow of Geomagnetically Induced Currents (GIC) in an electrical power transmission grid. In this paper, a new technique for mapping the location of transmission equipment for the purposes of GIC simulation is proposed. The DC modeling of autotransformers for the purpose GIC studies is discussed. The simulator models the electrical power system as an admittance matrix. GIC results for two study systems as obtained from the developed simulator are compared with those obtained from the Electromagnetic Transients Program (EMTP). Finally, the simulator is applied to the entire Hydro One 500/230 kV transmission system to predict GICs. This simulation will help Hydro One plan its mitigation strategies to protect against geomagnetic storms.

Modeling and mitigation of Geomagnetically Induced Currents on a realistic power system network

This paper utilizes a novel technique developed to correlate the magnitude of Geomagnetically Induced Current (GIC) with the reactive power absorbed by the transformers magnetizing reactance to model the impacts of GIC in load flow studies. A portion of an actual 500 kV power system segment is modeled and the impacts of a GIC event are considered on the voltage profile of the segment. Different what-if scenarios are considered and a potential operational mitigation strategy is proposed. It is shown that an improved visibility of GIC within the network can help the system operator take more informed and effective measures to protect the system during GIC events.

Determination of the spectrum of frequencies generated by a saturated transformer

This paper develops a technique to model the frequency response of a saturated transformer. This technique is used to determine the range of frequencies that will be generated when a transformer experiences saturation due to an injection of typically low frequency currents. This paper examines the case when a power transformer is saturated due to geomagnetically induced currents (GIC) caused by solar storms. The proposed technique is validated for a study system utilizing EMTDC/PSCAD simulations. The results from this technique are also correlated with those from a Hydro Quebec study. This technique will be useful in understanding the impact of transformer saturation on neighbouring equipment and as well as on FACTS controllers, and help design appropriate mitigation strategies.

Bibliography of FACTS 2011: Part II IEEE Working Group report

This paper presents the second part of the Bibliography of FACTS technology for 2011. It provides a listing of various journal and conference papers in this area. This Bibliography includes papers published until November 2011. If this paper is granted revise and resubmit status, the Working Group will update this bibliography to include all papers published till the end of year 2011 and make it more complete.

Bibliography of FACTS 2009 — Part 1 IEEE working group report

This paper presents a Bibliography of FACTS technology for 2009. It provides a listing of various journal and conference papers in this area.