Adaptive Zero-Sequence Overcurrent Criterion for Earth Fault Detection for Fault Current Passage Indicators in Resistor Grounded Medium Voltage Networks

Olejnik, Bartosz

doi:10.1109/access.2021.3076022

Cited by 13 publications

(10 citation statements)

References 31 publications

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“…These measures include: shortening the fault current interruption times in selected switchgear bays, or reducing the earthing electrode resistance in selected MV/LV substations to the calculated values. 0.25 5 (1) 0.30 3 (1) 0.1% 0.20 10 (1) 0.25 5 (1) 0.30 3 (1) 02 1.0% (2) 0.35 3 (3) 0.1% 0.20 n/a 0.35 5 (2) 0.35 3 (3) (1) for stations 0101, 0102, 0103, 0104, (2) for stations 0401, 0403, (3) for stations 0401, 0402, 0403.…”

Section: Exemplary Application Of Method-analysis Of a Real 15 Kv Net...mentioning

confidence: 99%

“…Therefore, the choice of the method used for neutral point earthing is a complex issue with multiple aspects. In practice, several options [2,3] are available, and systems can be classified into two basic groups:…”

Section: Introductionmentioning

confidence: 99%

“…Earth fault overvoltages can be limited by applying resistance earthing of the neutral point of the network (Figure 1c). An additional advantage of this solution is the high reliability of protection operation [3] and the short fault current interruption times. The main disadvantage of this solution is the high risk of electric shock in the MV/LV substations, which is a result of the high values of earth fault currents.…”

Section: Introductionmentioning

confidence: 99%

“…liability of protection operation [3] and the short fault current interruption times. The main disadvantage of this solution is the high risk of electric shock in the MV/LV substations, which is a result of the high values of earth fault currents.…”

Section: Introductionmentioning

confidence: 99%

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Statistical Assessment of Electric Shock Hazard in MV Electrical Power Substations Supplied from Networks with Non-Effectively Earthed Neutral Point

et al. 2022

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This paper focuses on the evaluation of the electric shock hazard accompanying earth faults in a non-effectively earthed medium-voltage (MV) electrical power network. This hazard depends on the duration and value of the fault current. While the fault current depends on several factors, the most important is the neutral point earthing method. The value of the fault current affects the earthing-electrode voltage value, being the basis for the assessment of electric shock hazard in MV/LV substations. The earthing-electrode voltage is also influenced by the resistance of the substation earthing, which in practice is random. Therefore, an original statistical evaluation method for assessing the electric shock hazard has been developed and presented in this paper. It is based on a statistical model of the MV/LV substation earthing resistance, worked out on the basis of experiments and measurements in real electrical power networks. This method can be used for the determination of statistical distributions of earthing-conductor voltages in real electrical power networks, and on this basis, the MV/LV substations with rates of electric shock hazard that are too high can be indicated. This also makes it possible to determine the longest permissible fault current interruption times or the highest permissible earthing resistances for specific substations. This method is also applicable when selecting the neutral point earthing method. The developed method was used in all of the above proposed areas by performing calculations on a model of a real 15 kV network with the neutral point earthed by a resistor. This analysis proves the practicability of the method both at the stage of designing power networks, and when a change in the neutral point earthing method in existing networks is being considered. Particularly valuable is also the statistical model of an earthing electrode resistance, developed on the basis of measurements in 2408 MV/LV substations, which may also be applicable in the future studies.

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Section: Exemplary Application Of Method-analysis Of a Real 15 Kv Net...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Statistical Assessment of Electric Shock Hazard in MV Electrical Power Substations Supplied from Networks with Non-Effectively Earthed Neutral Point

et al. 2022

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“…Earth faults are one of the most common fault types in the distribution system networks. It is estimated that earth faults stand for 70-80% of faults [1][2][3][4][5]. The occurrence of earth faults is connected with many negative phenomena-the risk of electrocution, transient overvoltages or thermal damages due to current flow [6].…”

Section: Introductionmentioning

confidence: 99%

Monitoring, Detection and Locating of Transient Earth Fault Using Zero-Sequence Current and Cable Screen Earthing Current in Medium Voltage Cable and Mixed Feeders

Łowczowski

Olejnik

2022

Energies

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This paper presents the final development of an expert system utilizing a measurement of cable screen earthing transient current. The developed system allows for identification and location of earth fault in underground cable and mixed lines (underground cable and overhead line) and monitoring of an earthing system and cable screen connections. The unique feature of the developed earth fault locating system is the possibility of identification of line type and branch of the MV underground cable or mixed feeder under earth fault conditions. As a result, the time to remove failure can be greatly reduced and the number of earth fault indicators installed in the distribution network can also be reduced. Unfortunately, in order to operate properly, the previously developed system requires a fundamental—50 Hz component of the measured zero-sequence cable core current and cable screen earthing current; therefore, short transient earth faults without steady-state earth fault currents cannot be localized and categorized even though the transient earth faults have a negative impact on the power system. According to measurements performed by the authors, transient earth faults are relatively frequent, which causes stress to insulation. The number of transient earth faults may be reduced by ensuring proper maintenance of the distribution system. Unfortunately, because of the very large area of the distribution feeder, often in the range of tens of kilometers or even around a hundred kilometers, and many potential causes of earth faults, it is very difficult to localize the transient earth fault and determine the cause of the earth fault. Herein, we present the possible causes of transient earth faults and methods developed for the analysis of transient earth faults. Moreover, the novel algorithm for transient earth fault detection and location is proposed. The proposed algorithm has a self-learning capability and can identify branches of the distribution feeder under transient earth fault conditions. The effectiveness of the proposed algorithm is confirmed thanks to the performed network experiment.

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Identification of Single-Phase Line Break Fault Direction Based on Local Voltage Information in Small Current Grounding System Considering the Impact of DG

Yang,

Li,

et al. 2023

IEEE Access

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Line break faults commonly occur in distribution networks and pose the risk of electric shocks to nearby individuals and animals. This study aims to address the challenge of identifying the direction of a line break fault. Specifically, we develop a model for a single-phase line break fault in a small current grounding system and focus on analyzing the steady-state voltage changes on both sides of the fault point. The voltage characteristics of the ungrounded system and the resonant grounding system are compared and summarized. Based on these characteristics, a more reliable method is proposed to identify the single-phase line break fault direction by utilizing two types of local voltage information: the magnitude of the line-to-line voltage and the sequence of phase-to-earth voltage. Additionally, we analyze the effects of V/V wired potential transformer (PT) and distributed generation (DG). The proposed method can accommodate the high utilization rate of V/V wired PT in distribution networks and its practicality is unaffected by the connection of DG to the distribution network. The above analysis is verified through simulations. The findings of this study demonstrate that the direction of a single-phase line break fault can be reliably detected using local voltage information and can be further localized with the assistance of communication, thereby improving the level of relay protection in distribution networks.

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Adaptive Zero-Sequence Overcurrent Criterion for Earth Fault Detection for Fault Current Passage Indicators in Resistor Grounded Medium Voltage Networks

Cited by 13 publications

References 31 publications

Statistical Assessment of Electric Shock Hazard in MV Electrical Power Substations Supplied from Networks with Non-Effectively Earthed Neutral Point

Statistical Assessment of Electric Shock Hazard in MV Electrical Power Substations Supplied from Networks with Non-Effectively Earthed Neutral Point

Monitoring, Detection and Locating of Transient Earth Fault Using Zero-Sequence Current and Cable Screen Earthing Current in Medium Voltage Cable and Mixed Feeders

Identification of Single-Phase Line Break Fault Direction Based on Local Voltage Information in Small Current Grounding System Considering the Impact of DG

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