scholarly journals Detection and Location of Earth Fault in MV Feeders Using Screen Earthing Current Measurements

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1293 ◽  
Author(s):  
Krzysztof Lowczowski ◽  
Jozef Lorenc ◽  
Jozef Zawodniak ◽  
Grzegorz Dombek
Keyword(s):  
Fault Location ◽  
Overhead Lines ◽  
Earth Fault ◽  
Ground Fault ◽  
Detection And Identification ◽  
Zero Sequence ◽  
Network Experiment ◽  
System Configurations ◽  
Zero Sequence Voltage ◽  
Core Current

The paper analyzes the utilization of cable screen currents for earth fault identification and location. Attention is paid on cable and mixed feeders—cable and overhead lines. The principle of operation is based on utilization of 3 criterion values: Ratio of cable screen earthing current and zero sequence cable core current—RF110/15, phase shift between cable screen earthing current and zero sequence cable core current—α and cable screen admittance defined as a ratio of cable screen earthing current and zero sequence voltage—Y0cs. Earth fault location is possible thanks to discovered relation between RF110/15 and α, whereas Y0cs allows for reliable detection of earth faults. Detection and identification are very important because it allows to increase the reliability of supply—reduce downtime and number of consumers affected by the fault. The article presents a phase to ground fault current flow for different power system configurations. At the end solution, which improves location capabilities is proposed. The solution is analyzed in PSCAD software and verified by network experiment.

scholarly journals The influence of the network asymmetry on the settings and sensitivity of an earth fault protection using higher harmonics

2019 ◽  
Vol 84 ◽  
pp. 02008
Author(s):  
Lubomir Marciniak ◽  
Mateusz Piątek
Keyword(s):  
Reactive Power ◽  
Higher Harmonics ◽  
Medium Voltage ◽  
Earth Fault ◽  
Power Setting ◽  
Zero Sequence ◽  
The Asymmetry ◽  
Supply Voltages ◽  
Zero Sequence Voltage

Detection of high resistance earth faults in medium voltage networks is an important problem due to ineffectiveness of traditional earth fault protections. Such short circuits can be detected by the criterion of a reactive power of higher harmonics for zero sequence current and voltage. The main problem is determination of the power setting value in the protection, which depends on the asymmetry of phase-to-earth capacitances and higher harmonics in supply voltages, which are generated by non-linear loads. The intensive tests of the asymmetry of the zero sequence currents and voltages for harmonics and their reactive power have been carried out in 15 kV compensated network as a function of all relevant parameters, i.e.: maximum capacitance deviation of the network and protected line, percentage content of harmonics in supply voltages, capacitive current of the network and the line. It has been shown that third harmonics of the zero sequence voltage and current are the best suited for practical use, since the asymmetry reactive power of these components is the smallest among the considered harmonics and the protection sensitivity will be the highest.

The Identification of Single-Line-to-Ground Fault in Neutral Un-Effectively Earthed System

2013 ◽  
Vol 805-806 ◽  
pp. 673-677
Author(s):  
Feng Xiang Dong ◽  
Chao Guo Tang ◽  
Zheng Yuan ◽  
Wen Hai Zhang
Keyword(s):  
Traditional Method ◽  
Single Line ◽  
Fault Line ◽  
Fault Line Selection ◽  
High Impedance ◽  
Ground Fault ◽  
Large Numbers ◽  
Zero Sequence ◽  
Line Selection ◽  
Zero Sequence Voltage

The correct and reliable identification of SLG(single-line-to-ground) fault is the foundation of starting the fault line selection and location device in neutral un-effectively earthed system. The traditional method based on the zero sequence voltage is invalid when the fault happens with high impedance, because the zero sequence voltage in bus is small. So a new algorithm based on the variation of voltage including the zero sequence voltage and phase voltages is proposed. The algorithm is not affected by the unbalance of system, and the sensitivity and the reliability of the algorithm are considered simultaneously. The algorithm is proved effectively by the large numbers of simulations using PSCAD/EMTDC program.

scholarly journals Dynamic stability of the functioning of current earth fault directional protection in networks with isolated neutral

Vestnik IGEU ◽  
2019 ◽  
pp. 30-41
Author(s):  
Yu.D. Kutumov ◽  
V.V. Tyutikov ◽  
T.Yu. Shadrikova ◽  
V.A. Shuin
Keyword(s):  
Dynamic Stability ◽  
Electrical Networks ◽  
Medium Voltage ◽  
Earth Fault ◽  
Fault Protection ◽  
Zero Sequence ◽  
Protection Devices ◽  
High Dynamic ◽  
Isolated Neutral ◽  
Zero Sequence Voltage

In distribution 6–10 kV networks with an insulated neutral for earth fault protection, zero sequence current directional protection devices are commonly used. According to the operation data, the main disadvantage of such kind of protection is the possibility of their functioning failures in transient conditions with the most dangerous for network intermittent arc earth faults. It is known that most earth faults in 6–10 kV networks, primarily in the initial stage of insulation damage, have an intermittent arc. Operation failures of zero sequence current directional protection in case of arc faults reduce the operational reliability of the protected network and, as a result, the reliability of power supply to consumers. Nowadays, new developments of electrical power systems relay protection devices, including earth fault protection of medium voltage distribution electrical networks, are implemented only on a microprocessor base. Therefore, the selection and justification of the implementation principles of zero sequence current directional protection which can provide high dynamic stability of functioning is a relevant objective. When analyzing the dynamic stability of the functioning of zero sequence directional current protection, regarding the complexity of transients during intermittent arc earth faults in medium voltage electrical networks with an isolated neutral, the simulation in Matlab using SimPowerSystem and Simulink was carried out. This study focuses on transient currents and voltages as the main factor influencing dynamic stability of the functioning of zero sequence current directional protection. The impact of other factors, for example, the inaccuracies of the primary zero sequence current and voltage transducers, the scheme of formation of compared quantities, etc. was not taken into account in simulation models. The study has allowed determining the causes of possible functioning failures of digital current earth fault directional protection in dynamic operation modes. It has been shown that the usage of orthogonal components of fundamental frequency of zero sequence voltage and current in current directional protection devices eliminates the failure of their operation with any kind of arc earth faults. To ensure high dynamic stability of operation under the influence of transients during arc intermittent earth faults, current directional protection for this type of damage should be performed on the basis of monitoring the phase relationships of the fundamental frequency components of 50 Hz of zero sequence voltage and current, but not their full values.

Study on Single-Phase Earth Fault Location Method in Mine Non-Effectively Grounded Network Based on WAMS

2014 ◽  
Vol 602-605 ◽  
pp. 2110-2113
Author(s):  
Dan Lu ◽  
Jun Qiang Liu ◽  
Xiu Gang Yin
Keyword(s):  
Fault Location ◽  
Single Phase ◽  
Load Capacity ◽  
Logical Relationship ◽  
Location Method ◽  
Earth Fault ◽  
Zero Sequence ◽  
Supply Model ◽  
Relationship Of ◽  
New Location

In allusion to the low reliability and sensitivity of existing single-phase earth fault location method, this article proposed a new location method based on WAMS in mine non-effectively grounded network. It analyzed the logical relationship of zero-sequence current of each branch when single-phase earth fault occurred and deduced zero-sequence current formulae of each branch. The detailed description is given to calculating differential variable of zero-sequence current and explicating principle and realization of fault section location. The coal mine power supply model based on WAMS is introduced and the scheme was verified by simulation via MATLAB and calculation via Fast Fourier Transform. The results indicate that it avoids influences by load capacity and the voltage initial phase angle, then effectively enhances fault location reliability and sensitivity.

scholarly journals Evaluation of earth fault location algorithm in medium voltage distribution network with correction technique

2019 ◽  
Vol 9 (3) ◽  
pp. 1987
Author(s):  
N. S. B. Jamili ◽  
M. R. Adzman ◽  
S. R. A. Rahim ◽  
S. M. Zali ◽  
M. Isa ◽  
...  
Keyword(s):  
Fault Location ◽  
Distribution Network ◽  
Distance Estimation ◽  
Voltage Distribution ◽  
Medium Voltage ◽  
Earth Fault ◽  
Ground Fault ◽  
The Earth ◽  
Correction Technique ◽  
Location Algorithm

This paper focused on studying an algorithm of earth fault location in the medium voltage distribution network. In power system network, most of the earth fault occurs is a single line to ground fault. A medium voltage distribution network with resistance earthing at the main substation and an earth fault attached along the distribution network is modeled in ATP Draw. The generated earth fault is simulated, and the voltage and current signal produced is recorded. The earth fault location algorithm is simulated and tested in MATLAB. The accuracy of the earth fault location algorithm is tested at several locations and fault resistances. A possible correction technique is explained to minimize the error. The results show an improvement fault location distance estimation with minimum error.

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