S-Transform Based Protection Scheme for Distribution System Integrated with Solar Power Plant
01 Nov 2019-
TL;DR: Stockwell transform based protection scheme has been proposed to detect and classify faults in a distribution network integrated with a solar photo voltaic power plant (SPV) and the immunity of the proposed algorithm to switching transients, energization/de-energization of power components and noisy environment has been established.
Abstract: Integration of distributed generation (DG) sources poses new protection challenges in distribution system. The fault current characteristics change due to bidirectional flow of current and unpredictable nature of DG sources. In this work, Stockwell transform based protection scheme has been proposed to detect and classify faults in a distribution network integrated with a solar photo voltaic power plant (SPV). The post fault current transients measured over a moving window at the substation are decomposed using S- Transform to obtain the peak magnitude of second harmonic content which is defined as fault index. This fault index is compared with a threshold (T F ) to detect and classify faults. The proposed algorithm has been successfully implemented on IEEE 13 bus system with numerous case studies involving variations of fault incidence angles and fault locations in MATLAB environment. The immunity of the proposed algorithm to switching transients, energization/de-energization of power components and noisy environment has also been established.
Citations
More filters
TL;DR: A fast protection algorithm based on Hilbert-Huang transform (HHT) is proposed in this article for islanding and fault detection, classification, and location in a distribution system penetrated by a solar renewable energy source.
9 citations
References
More filters
TL;DR: The S transform is shown to have some desirable characteristics that are absent in the continuous wavelet transform, and provides frequency-dependent resolution while maintaining a direct relationship with the Fourier spectrum.
Abstract: The S transform, which is introduced in the present correspondence, is an extension of the ideas of the continuous wavelet transform (CWT) and is based on a moving and scalable localizing Gaussian window. It is shown to have some desirable characteristics that are absent in the continuous wavelet transform. The S transform is unique in that it provides frequency-dependent resolution while maintaining a direct relationship with the Fourier spectrum. These advantages of the S transform are due to the fact that the modulating sinusoids are fixed with respect to the time axis, whereas the localizing scalable Gaussian window dilates and translates.
2,752 citations
"S-Transform Based Protection Scheme..." refers background in this paper
...The S-transform of a discrete time series s(kT ) is given by (letting f → n NT and τ → jT ) [10]...
[...]
...The S-transform of a function is defined as a CWT with a specific mother wavelet multiplied by the phase factor [10] S(τ, f) = eW (τ, d) (2) where the mother wavelet is defined by the relation...
[...]
Journal Article•
TL;DR: The S transform as discussed by the authors is an extension to the ideas of the Gabor transform and the Wavelet transform, based on a moving and scalable localising Gaussian window and is shown here to have characteristics that are superior to either of the transforms.
Abstract: The S transform, an extension to the ideas of the Gabor transform and the Wavelet transform, is based on a moving and scalable localising Gaussian window and is shown here to have characteristics that are superior to either of the transforms. The S transform is fully convertible both forward and inverse from the time domain to the 2-D frequency translation (time) domain and to the familiar Fourier frequency domain. Parallel to the translation (time) axis, the S transform collapses as the Fourier transform. The amplitude frequency-time spectrum and the phase frequency-time spectrum are both useful in defining local spectral characteristics. The superior properties of the S transform are due to the fact that the modulating sinusoids are fixed with respect to the time axis while the localising scalable Gaussian window dilates and translates. As a result, the phase spectrum is absolute in the sense that it is always referred to the origin of the time axis, the fixed reference point. The real and imaginary spectrum can be localised independently with a resolution in time corresponding to the period of the basis functions in question. Changes in the absolute phase ofa constituent frequency can be followed along the time axis and useful information can be extracted. An analysis of a sum of two oppositely progressing chirp signals provides a spectacular example of the power of the S transform. Other examples of the applications of the Stransform to synthetic as well as real data are provided.
2,323 citations
TL;DR: Test results indicate that the proposed relaying scheme can effectively protect the microgrid against faulty situations, including wide variations in operating conditions.
Abstract: This paper presents an intelligent protection scheme for microgrid using combined wavelet transform and decision tree. The process starts at retrieving current signals at the relaying point and preprocessing through wavelet transform to derive effective features such as change in energy, entropy, and standard deviation using wavelet coefficients. Once the features are extracted against faulted and unfaulted situations for each-phase, the data set is built to train the decision tree (DT), which is validated on the unseen data set for fault detection in the microgrid. Further, the fault classification task is carried out by including the wavelet based features derived from sequence components along with the features derived from the current signals. The new data set is used to build the DT for fault detection and classification. Both the DTs are extensively tested on a large data set of 3860 samples and the test results indicate that the proposed relaying scheme can effectively protect the microgrid against faulty situations, including wide variations in operating conditions.
258 citations
TL;DR: In this paper, a differential scheme for microgrid protection using time-frequency transform such as S-transform was proposed to register the fault patterns in the microgrid at grid-connected and islanded mode.
Abstract: The study presents a differential scheme for microgrid protection using time-frequency transform such as S-transform Initially, the current at the respective buses are retrieved and processed through S-transform to generate time-frequency contours Spectral energy content of the time-frequency contours of the fault current signals are calculated and differential energy is computed to register the fault patterns in the microgrid at grid-connected and islanded mode The proposed scheme is tested for different shunt faults (symmetrical and unsymmetrical) and high-impedance faults in the microgrid with radial and loop structure It is observed that a set threshold on the differential energy can issue the tripping signal for effective protection measure within four cycles from the fault inception The results based on extensive study indicate that the differential energy-based protection scheme can reliably protect the microgrid against different fault situations and thus, is a potential candidate for wide area protection
187 citations
"S-Transform Based Protection Scheme..." refers background in this paper
...A differential energy feature is proposed for microgird integrated with wind energy source in [7]....
[...]
TL;DR: In this article, a Hilbert-Huang Transform (HHT) based non-stationary signal processing algorithm has been implemented for the protection objective and the comparative assessment with that of S-transform, differential current is carried out in order to demonstrate the reliability of the proposed protection scheme with different case studies.
Abstract: Time-frequency-based differential scheme is proposed for microgrid protection using non-stationary signal analysis. The non-stationary signal processing algorithm Hilbert-Huang Transform (HHT) have been implemented for the protection objective and the comparative assessment with that of S-transform, differential current is carried out in order to demonstrate the reliability of the proposed protection scheme with different case studies. The series of simulation results demonstrates the efficacy of HHT, than that of S-transform in some critical cases such as high impedance fault where accurate detection is a challenge. The configuration of the microgrid test model has been developed in PSCAD with different distributed generation such as photovoltaic and wind generation system penetrated at different buses. Thus, it is found that the HHT scheme is quite reliable and efficient for fault detection objective.
131 citations
"S-Transform Based Protection Scheme..." refers methods in this paper
...Hilbert Huang transform is applied for microgrid protection in the presence of wind and solar energy sources in [4]....
[...]