Higher harmonics of zero sequence current and voltage as a source of information for single-phase earth fault protection.

Single-phase earth faults in networks with ungrounded neutral are common and belong to a wider class of high-impedance damage. The problem of protection against such damage is quite complex and has been actively studied around the world in recent decades. In this article, it is proposed to use the information contained in the high-frequency components of the current and voltage of the zero-sequence during the transient process of insulation damage for targeted protection. The method of selection of high-frequency components is considered. The possibility of using a Petersen coil in the network is considered, as well as the probable deviation from the resonant tuning of the Petersen coil. The peculiarities of the transient process depending on the instantaneous voltage at the moment of a short circuit are investigated. Simulation of single-phase short circuits with different active resistance in the short circuit place is carried out. The spectral composition of zero-sequence currents and voltages during the transient process is analyzed. The dependence of the power of high-frequency components on the quality of Petersen coil tuning, instantaneous voltage at the time of short circuit, and active resistance at the time of short circuit is investigated. The principle of protection is based on determining the direction of the total reactive power of the higher harmonics of currents and voltages of zero sequence and the numerically found derivatives. The results of mathematical modeling showed that at the moment when the phase is closed to the ground, due to the recharging of the capacitance of the phase conductors in currents and voltages of zero sequence, higher harmonics occur. The power of the harmonics from the second to the tenth can be compared with the power of the first harmonic and they should be used for protection. Positive results of work of the offered way of protection at mathematical modeling and at tests on a laboratory stand are received.

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Probabilistic Short Circuit Analysis on Zero-sequence Current in Single-phase Grounding Faults

2019 IEEE 3rd International Electrical and Energy Conference (CIEEC) ◽

10.1109/cieec47146.2019.cieec-2019456 ◽

2019 ◽

Author(s):

Shilei Guan ◽

Changkai Shi ◽

Jie Chen ◽

Jinwei Fu ◽

Haotian Gao ◽

...

Keyword(s):

Single Phase ◽

Short Circuit ◽

Circuit Analysis ◽

Zero Sequence ◽

Short Circuit Analysis

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Analysis of a Dry-type Reactor Fault Based on COMSOL Thermal Field Simulation and High Frequency Pulse Oscillations

MATEC Web of Conferences ◽

10.1051/matecconf/201817302027 ◽

2018 ◽

Vol 173 ◽

pp. 02027

Author(s):

LUO Xin ◽

WANG Shuai-yi ◽

WANG Yao ◽

GU Yu

Keyword(s):

High Frequency ◽

Single Phase ◽

Thermal Field ◽

Short Circuit ◽

High Frequency Oscillation ◽

Reactor Operation ◽

Type Reactor ◽

Field Simulation ◽

Turn Insulation ◽

Frequency Pulse

For a single-phase earth fault of 35 kV dry-type reactor, the 5th package area is found with serious turn-to-turn short circuit after it conducts the DC resistance test, turn-to-turn insulation test of high frequency oscillation pulse and rework disassembly. The turn-to-turn short circuit of resistance will lead to wire fusing, which makes the conventional pre-test projects have limitations. With COMSOL finite element thermal field simulation of the fault 35kV dry-type reactor, the temperature distribution result of the reactor indicates that the hottest point is at the 6th package during the reactor operation and the temperature rises 73.75K. In addition, the temperature rises of the 5th, 7th, 14th, 15th package is also higher than other packages, which easily causes device failure due to insulation deterioration. Through the analysis and thermal field simulation of the test for failed reactor, it can provide the reference basis for equipment design, manufacture, daily repair and maintenance.

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Automatic Tuning Arc Suppression Coil Current in a Small Grounding System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.620.398 ◽

2014 ◽

Vol 620 ◽

pp. 398-401 ◽

Cited By ~ 1

Author(s):

Hui Lin Zhang ◽

Yu Bo Zhao ◽

Feng Zhen Liu

Keyword(s):

Common Good ◽

Single Phase ◽

Short Circuit ◽

Neutral Point ◽

Automatic Tuning ◽

Normal Operation ◽

Ground Fault ◽

Arc Suppression Coil ◽

Current Flows ◽

Petersen Coil

Equipped Petersen coil systems can compensate for the capacitance of the line current, the single-phase ground fault current flows through the capacitor grounding point for the minimum point of the arc of a reliable ground fault arc , to avoid reigniting , prevent arcing ground fault point phase faults caused by short circuit . But will also prevent the neutral point displacement due to different switching operation of single-phase disconnection caused by other factors , to avoid the neutral point voltage is too high, the threat of insulation safety equipment . In addition Petersen coil in the normal operation of the power grid , and can effectively prevent resonance over-voltage , prevent equipment damage caused thereby , better protection of system security , stability, and high-quality operation. Automatic tuning arc suppression coil can meet the common good basis to eliminate the role of the Petersen coil grid resonance occurs , install and use the effect is significant.

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Analisis Pengaruh Kompensasi Impedansi Urutan Nol (Kzn) terhadap Kehandalan Sistem Proteksi Rele Jarak (Distance Relay) pada Penghantar Harapan Indah di Gardu Induk Plumpang

RESISTOR (elektRonika kEndali telekomunikaSI tenaga liSTrik kOmputeR) ◽

10.24853/resistor.4.1.1-6 ◽

2021 ◽

Vol 4 (1) ◽

pp. 1

Author(s):

Deni Almanda ◽

Juniyanto Juniyanto

Keyword(s):

Single Phase ◽

Short Circuit ◽

Relay Protection ◽

Protection System ◽

Distance Relay ◽

Two Phase ◽

Test Tool ◽

Three Phase ◽

Zero Sequence ◽

Short Circuit Fault

Pada saat terjadi gangguan hubung singkat di saluran transmisi Gardu Induk Plumpang, rele jarak berfungsi sebagai proteksi utama. Penelitian ini bertujuan untuk mengetahui pengaruh kompensasi impedansi urutan nol (kzn) terhadap kehandalan sistem proteksi rele jarak (distance relay) pada penghantar harapan indah di Gardu Induk Plumpang. Setting rele jarak yang didapatkan dari PT PLN (Persero) UPT Pulogadung disimulasikan menggunakan alat uji Omicron. Hasil simulasi gangguan hubung singkat satu fasa, gangguan hubung singkat dua fasa, dan gangguan hubung singkat tiga fasa menggunakan setting lama Z1 = 2.58 Ω, Z2 = 3.87 Ω, dan Z3 = 7.30 Ω, kZn = 0.93 Ω < -0.4° rele jarak tidak bekerja selektif, maka dilakukan resetting. Hasil resetting rele jarak yaitu Z1 = 2.58 Ω, Z2 = 3.87 Ω, dan Z3 = 7.30 Ω, kZn = 0.68 Ω < -0.6°. Setelah dilakukan resetting dan disimulasikan gangguan hubung singkat satu fasa, gangguan hubung singkat dua fasa, dan gangguan hubung singkat tiga fasa, rele jarak bekerja secara handal. Kesimpulannya kZn dapat mempengaruhi kehandalan sistem proteksi rele jarak pada penghantar harapan indah di Gardu Induk Plumpang.In the event of a short circuit in the transmission line of the Plumpang Substation, the distance relay serves as the main protection. This study aims to determine the effect of zero sequence impedance compensation (kzn) on the reliability of the distance relay protection system at the Harapan Indah conductor at the Plumpang Substation. The distance relay setting obtained from PT PLN (Persero) UPT Pulogadung was simulated using the Omicron test tool. Simulation results of single phase short circuit, two phase short circuit, and three phase short circuit using the old setting Z1 = 2.58 Ω, Z2 = 3.87 Ω, and Z3 = 7.30 Ω, kZn = 0.93 < -0.4° relay distance does not works selectively, then resetting is done. The results of resetting the distance relay are Z1 = 2.58 Ω, Z2 = 3.87 Ω, and Z3 = 7.30 Ω, kZn = 0.68 < -0.6°. After resetting and simulating single-phase short circuit, two phase short circuit, and three phase short circuit fault, the distance relay works reliably. In conclusion, kZn can affect the reliability of the distance relay protection system on the beautiful hope conductor at the Plumpang Substation.

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Research on Detection Method of Transformer Interturn Short Circuit Based on Wavelet Analysis

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.521.358 ◽

2014 ◽

Vol 521 ◽

pp. 358-361

Author(s):

Yu Sheng Quan ◽

Zong Cheng Zhang ◽

Guang Chen ◽

Dai Juan Wang

Keyword(s):

High Frequency ◽

Short Circuit ◽

Frequency Component ◽

Diagnostic Methods ◽

High Frequency Component ◽

Transformer Winding ◽

Ground Current ◽

Frequency Components ◽

Circuit Fault Diagnosis ◽

Experimental Data Analysis

Distribution transformer is an important device in the power supply system, once its failure can cause power outages. According to statistics, 70% -80% of the transformer accident was caused by a short circuit between the transformer turns. Based on the large number of experimental data analysis and processing, a new inter-turn short circuit transformer diagnostic methods is proposed. In this paper, the ground current of transformer core as the signal source, Using wavelet multi-resolution technology the signal wavelet multiscale decomposition, the decomposition of different signals of the same scale, get the high frequency components of the signal, achieve short-circuit fault diagnosis between transformer winding turns by comparing the number of the high-frequency component contained in different signals in the decomposition of the same scale. To illustrate the effectiveness of the method, the paper through a series of experiments and data processing, verify the effectiveness and feasibility of the method.

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Faulted Section Identification Method Based on the Transient Current Distribution for the NUGS

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1070-1072.855 ◽

2014 ◽

Vol 1070-1072 ◽

pp. 855-860

Author(s):

Ben Ren Pan ◽

Kan Sheng Yu ◽

Guo Qiang Xie ◽

Zai De Xu ◽

Jin Zou ◽

...

Keyword(s):

Theoretical Analysis ◽

Current Distribution ◽

Simulation Study ◽

Single Phase ◽

Transient Current ◽

Fault Identification ◽

Identification Method ◽

Zero Sequence ◽

The Impact ◽

Petersen Coil

The faulted feeder selection and fault identification under the condition of single-phase earth fault in the neutral un-effectual grounded system (NUGS) has long been a problem. As a matter of fact, existing methods that have been proposed may face some difficulty in the case of some scenarios, as the impact of the Petersen coil must be taken into consideration, or when the accurate location of the faulted point is required and the zero-sequence current cannot be measured. To against this, a novel faulted section identification method based on the transient current distribution is put forward by means of theoretical analysis and simulation study. It is shown by the results that this methods can give accurate location of the fault by comparing the transient RMS value of the upstream and the downstream of the fault point, even though the Petersen coil is switched in.

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The influence of changing resistance on the determination accuracy of short circuits in power lines

E3S Web of Conferences ◽

10.1051/e3sconf/202128801091 ◽

2021 ◽

Vol 288 ◽

pp. 01091

Author(s):

Serdar Nazarov ◽

Gurbangulych Kelov ◽

Berdimyrat Gochyev

Keyword(s):

Single Phase ◽

Short Circuit ◽

Stable State ◽

Short Circuit Current ◽

Scientific Work ◽

Electric Power System ◽

Electrical Networks ◽

Zero Sequence ◽

Short Circuits ◽

Maintenance Personnel

In high-voltage electrical networks, the occurrence of short circuits leads to forced interruptions in the power supply of large consumers and disruptions in intersystem communications. More than 65% of all types of occurring short circuits are single-phase short circuits [1]. In a single-phase short circuits (SPSC), a change in the zero sequence resistance (ZSR) especially significantly affects the inaccuracy in detection of damage sites (DDS). When choosing DDS methods, preference is given to remote methods according to the parameters of the emergency conditions (PEC), which are recorded by special instruments or determined from the oscillograms of emergency conditions. The use of modern microprocessor-based relay protection and automation devices (RPA) [26] or emergency event recorders allow viewing the oscillograms of emergency events. In a branched 110 kV network with a complex configuration, the DDS accuracy is influenced by a change in the ZSR. Averaging of specific parameters often leads to erroneous results. The choice of one value from the oscillograms puts the maintenance personnel in difficulty. In the scientific work, the influence of changes in the ZSR on the accuracy of the DDS is considered. The changes in the ZSR are influenced by the position of the on-load voltage regulator (OLTC) switches of transformers with a grounded neutral. In the work, for a more accurate record of the specific parameters of the network, a calculation program has been compiled, which allows making changes in the calculated specific parameters of the network. To determine the short-circuit current from the oscillograms, it is proposed to determine the stable state of accidents in which the current value will be approximately the same. The analysis of the oscillograms of SPSC in 110-220 kV networks in the southern part of the electric power system of Turkmenistan has been carried out.

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The New Methodology of Diagnosis for Transformer Inter-Turn Short Circuit Based on Wavelet Analysis

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.672-674.1155 ◽

2014 ◽

Vol 672-674 ◽

pp. 1155-1158

Author(s):

Yu Sheng Quan ◽

Ning Chen ◽

Zi Jian Wang ◽

Pu Xin Shi

Keyword(s):

High Frequency ◽

Short Circuit ◽

Frequency Component ◽

Diagnostic Methods ◽

High Frequency Component ◽

Transformer Winding ◽

Frequency Components ◽

Circuit Fault Diagnosis ◽

Experimental Data Analysis ◽

Transformer Core

Based on the large number of experimental data analysis and processing, a new inter-turn short circuit transformer diagnostic methods is proposed. In this paper, take the grounding current of transformer core as the signal source. Using wavelet multi-resolution technology the signal wavelet multiscale decomposition, we can get high frequency components of the signal. Achieve short-circuit fault diagnosis between transformer winding turns by comparing the number of the high-frequency component contained in different signals in the decomposition of the same scale.

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Simulations of high-resolution images of amorphous silicon films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010014419x ◽

1986 ◽

Vol 44 ◽

pp. 544-545

Author(s):

G. Y. Fan ◽

J. M. Cowley

Keyword(s):

Electron Microscope ◽

High Frequency ◽

Fourier Transformation ◽

Amorphous Materials ◽

Low Frequency ◽

Chromatic Aberration ◽

Structure Information ◽

Frequency Components ◽

High Resolution Images ◽

Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

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