Seong-Eun Jin

Time-varying Harmonics Measurement and Evaluation of the High Speed Electric Train Loads

High speed electric trains have nonlinear loads including converters and inverters for the control synchronous motors. Harmonics produced by these devices are large, but also have noticeable time varying characteristics. Since the large loads are supplied from the power system grid, it must be recognized that not only will the system of utility be impacted, but neighboring customer system could be impacted as well. In this paper time-varying harmonics for high speed electric train loads are measured and evaluated by international harmonic standards IEEE Std. 519 and IEC 61000-3-6 using a cumulative probablistic approach.

A Study on the Harmonics Measurement and Assessment of the Electrolyzer Loads

Heavy chemical industries have nonlinear loads including elecrolyzers. AC-DC converters are the most widely used in an elecrolysis in a chemical plant. The electrolysis consists of AC-DC converter groups connected in parallel at the DC side. The converter operations cause harmonic currents and create distortions on the sinusoidal voltage of the AC power system. This paper provides an in depth analysis on harmonics field measurement for the electrolyzer loads and harmonics assessment by the international harmonic standards IEC 61000-3-6 and IEEE 519-1992.

A Study on the Time-varying Harmonics Measurement, Assessment and Simulation of the Electric Arc Furnace Loads

Large steel industries have nonlinear loads such as electric arc furnaces. Harmonic field measurements have shown that the harmonic contents of a waveform varies with time. Direct application of the harmonic assessment to the snapshot measurements would result in ambiguous conclusions depending on which instant is sampled. A cumulative probablistic approach is the most commonly used method to solve time-varying harmonics. Harmonic simulations are performed to evaluate the harmonic voltage and current distortions throughout the system. This paper provides an in depth analysis on harmonics field measurement of the electric arc furnace loads, harmonics assessment by the international harmonic standards IEC 61000-3-6 and IEEE Std. 519 and harmonic simulation for the time-varying harmonics. The EDSA program was used as a simulation tool for the case study.

A Study on the Harmonics Effect of SVC in Electric Arc Furnace Loads

Large steel industries have time-varying nonlinear loads such as electric arc furnaces. These nonlinear loads generate harmonic currents and create distortions on the sinusoidal voltage of the power system. The main objective of the static var compensator is to maintain the rms voltage at the point of common coupling within the limit. In this research, harmonic mitigation studies were conducted with and without the SVC, and time-varying harmonics were evaluated according to the international harmonic standards (IEC 61000-3-6 and IEEE Std. 519) using a cumulative probabilistic approach.

Time-varying Harmonics Measurement and Assessment of the Electric Arc Furnace Loads

Large steel industries have nonlinear loads including electric arc furnaces and harmonic field measurements have shown that harmonic content of a waveform varies with time. Since the large loads are supplied from the power system grid, it must be recognized that not only will the system of utility be impacted, but neighboring customer system could be impacted as well. In this paper time-varying harmonics are evaluated by international harmonic standards IEEE Std. 519 and IEC 61000-3-6 using a cumulative probablistic approach.

A Study on the Harmonics Measurement, Assessment and Resonant Filter Application of the Electrolyzer Loads

Heavy chemical industries have nonlinear loads including electrolyzers. The electrolysis consists of AC-BC converters which generate harmonic currents and create distortions on the sinusoidal voltage of the power system. This paper provides in depth an analysis on harmonics field measurement for the electrolyzer loads, adding a single-tuned filter at the customer bus for reducing harmonic distortion and harmonic assessment by the international harmonic standards IEC 61000-3-6 and IEEE Std. 519. The EDSA program was used as a simulation tool for the case study.

A Study on the Fliker Effect of SVC in Electric Arc Furnace Loads

An electric arc furnace being used in the steel industry is a time-varying non-linear load causing voltage fluctuations to the power system. Flicker can be defined as the effect produced on the human visual perception by a changing emission of light lamps subjected to magnitude fluctuations of their supply voltage. The level of flicker depends on the amplitude, frequency and duration of the voltage fluctuations. In this paper, the voltage fluctuation problem in an 154[kV] system due to the electric arc furnace loads is investigated and the analysis results of the static var compensator application for the voltage flicker mitigation are presented and evaluated by the IEC 61000-3-7.

A study on the Transformer Capability Containing Hormonic Load Currents

The increasing use of nonlinear loads has resulted in an increase in the harmonic content of the load current for power transformers. Transformers subject to harmonic currents have higher losses and need to be derated. This paper presents a simple method for determining the capability of transformers to supply harmonic load currents and shows that the application of capacitor banks with a series connected reactor and harmonic filters will greatly increase the capability of transformers.. The EDSA program was used as a simulation tool for the case study.

Ground Impedance Characteristics Analysis of a Rod Type Grounding Electrode used for Distribution Systems

Grounding insures a reference potential point for electric devices and also provides a low resistance path for fault currents in the earth. The ground impedance as a function of frequency is necessary for determining its performance since fault currents could contain a wide range of frequencies. In this paper, the ground impedance of Magic rods which are commercially available has been measured in frequency ranging from 0[Hz] up to 100[kHz] and an equivalent circuit model, transfer function model of the ground impedance are identified from the measured values.

Ground Impedance Characteristics Analysis of a Copper Rod-type Grounding Electrode used for Electric Distribution Systems

Grounding insures a reference potential point for electric devices and also provides a low resistance path for fault currents in the earth. The ground impedance as a function of frequency is necessary for determining its performance since fault currents could contain a wide range of frequencies. A cower rod electrode is the most commonly used grounding electrode in electric distribution systems. In this paper, the ground impedance of cower rods has been measured in frequency ranging from 60[Hz] up to 100[kHz] and an equivalent circuit model, transfer function model of the ground impedance are identified from the measured values.