State estimation based determination of harmonic current contributions of iron and steel plants supplied from PCC

2015-10-22
Sezgin, Erhan
Göl, Murat
Salor, Özgül
In this paper, a state estimation based method is proposed to determine harmonic current contributions of iron and steel (I&S) plants supplied from a Point of Common Coupling (PCC). Due to highly nonlinear nature of the iron and steel plant operation, accurate estimation of the harmonic contributions of the individual plants is essential. In the proposed method, the nonlinear characteristics of the plants and the utility are modeled as harmonic current sources and the harmonic current contributions of loads are decoupled from the upstream effects on the basis of the sample-by-sample time-synchronized field measurements of load currents and voltage signals. Being a field-measurement-based method, it is necessary to mitigate the measurement errors of conventional voltage transformers at harmonic frequencies. Gross error of voltage transformers is reduced through calibration, while weighted least squares state estimation is used to reduce the Gaussian error of the current transformer and calibrated voltage transformer measurements. Using the estimated harmonic voltages and currents, harmonic contributions of all plants are determined by employing the Norton equivalent circuits of the plants together with the superposition theorem. The results have shown that the proposed method can be used as a successful estimation tool to determine the harmonic current contributions of all I&S plants supplied from the PCC. The proposed method eliminates the need for the usage of resistive-capacitive voltage transformers for accurate harmonic voltage measurements, which are expensive and cumbersome, while reducing the Gaussian measurement error of conventional voltage and current transformers at the same time, hence it provides accurate harmonic contributions of the EAF plants.

Suggestions

Determination of Harmonic Current Contributions of Plants Supplied from PCC Based on State Estimation
Sezgin, Erhart; Göl, Murat; Salor, Ozgul (2015-05-19)
In this paper, a state estimation based method is proposed to determine harmonic current contributions of plants supplied from a Point of Common Coupling (PCC). By using Weighted Least Squares (WLS) state estimation, it is aimed to improve harmonic voltage measurements acquired from conventional voltage transformers, which are employed commonly in the power systems. Using measured harmonic currents and estimated harmonic voltages, harmonic contributions of all plants have been determined by employing the No...
Determination of harmonic current contributions based on robust state estimation
Sezgin, Erhan; Göl, Murat; Salor, Ozgul (2018-01-01)
In this paper, a state estimation based method is proposed to determine harmonic current contributions of plants supplied from a point of common coupling (PCC). This work mainly aims to reduce gross error of capacitive voltage transformer (CVT) measurements at harmonic frequencies using robust weighted least absolute value (WLAV) state estimation method, which provides the optimum state estimates for harmonic voltages in the presence of a redundant enough measurement set. Estimated harmonic voltages are the...
State-Estimation-Based Determination of Harmonic Current Contributions of Iron and Steel Plants Supplied from PCC
Sezgin, Erhan; Göl, Murat; Salor, Ozgul (Institute of Electrical and Electronics Engineers (IEEE), 2016-05-01)
In this paper, a state-estimation-based method is proposed to determine harmonic current contributions of iron and steel (I&S) plants supplied from a point of common coupling (PCC). Due to highly nonlinear nature of the I&S plant operation, accurate estimation of harmonic contributions of the individual plants is essential. In the proposed method, the nonlinear characteristics of the plants and the utility are modeled as harmonic current sources and the harmonic current contributions of loads are decoupled ...
Angle of graph energy - A spectral measure of resemblance of isomeric molecules
Gutman, I; Türker, Burhan Lemi (2003-11-01)
A method, elaborated earlier by one of the present authors, for measuring the structural resemblance of isomeric alternant conjugated hydrocarbons, based on a graph-spectral quantity theta, called the angle of total pi-electron energy approach has been extended now to arbitrary molecules. Some general properties of theta have been established.
Identification of Harmonic Current Contributions of Iron and Steel Plants Based on Time-Synchronized Field Measurements-Part I: At PCC
Unsar, Ozgur; Salor, Ozgul; ÇADIRCI, IŞIK; Ermiş, Muammer (2014-11-01)
This is the first of a two-paper series, in which a field-data-based analytical method is proposed to determine the harmonic current contributions of each iron and steel (I&S) plant supplied from the point of common coupling (PCC) and the upstream loads at the utility side. The nonlinear characteristics of the plants and the utility are modeled as harmonic current sources, whereas the linear parts of the proposed model consist of passive circuit elements. In the proposed method, the harmonic current contrib...
Citation Formats
E. Sezgin, M. Göl, and Ö. Salor, “State estimation based determination of harmonic current contributions of iron and steel plants supplied from PCC,” 2015, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/42727.