scholarly journals Non-Directional Earth Fault Passage Indication in Isolated Neutral Distribution Networks

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4732
Author(s):  
Amir Farughian ◽  
Lauri Kumpulainen ◽  
Kimmo Kauhaniemi
Keyword(s):  
Single Phase ◽  
Distribution Networks ◽  
Voltage Measurement ◽  
Negative Sequence ◽  
Overhead Lines ◽  
New Methods ◽  
Zero Sequence ◽  
Isolated Neutral ◽  
Negative Sequence Current ◽  
Symmetrical Sequence

In this paper, two new methods for locating single-phase to ground faults in isolated neutral distribution networks are proposed. The methods are based on the analysis of symmetrical sequence currents. They are solely based on currents, not requiring voltage measurement. The first method employs only the zero sequence current and the second one utilizes the negative sequence current in combination with the zero sequence current. It is revealed why using only zero sequence current with a simple threshold is insufficient and may lead to false results. Using the proposed methods, earth faults with high resistances can be located in isolated neutral distribution networks with overhead lines or cables.

scholarly journals Earth Fault Location Using Negative Sequence Currents

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3759 ◽  
Author(s):  
Farughian ◽  
Kumpulainen ◽  
Kauhaniemi
Keyword(s):  
Fault Location ◽  
Single Phase ◽  
Distribution Networks ◽  
Practical Implementation ◽  
Negative Sequence ◽  
Medium Voltage ◽  
Different Types ◽  
Sequence Components ◽  
Zero Sequence ◽  
Negative Sequence Current

In this paper, a new method for locating single-phase earth faults on non-effectively earthed medium voltage distribution networks is proposed. The method requires only current measurements and is based on the analysis of the negative sequence components of the currents measured at secondary substations along medium voltage (MV) distribution feeders. The theory behind the proposed method is discussed in depth. The proposed method is examined by simulations, which are carried out for different types of networks. The results validate the effectiveness of the method in locating single-phase earth faults. In addition, some aspects of practical implementation are discussed. A brief comparative analysis is conducted between the behaviors of negative and zero sequence currents along a faulty feeder. The results reveal a considerably higher stability level of the negative sequence current over that of the zero sequence current.

Research on Electrical Characteristics of a Novel Balance Transformer with Asymmetrical Winding

2014 ◽  
Vol 536-537 ◽  
pp. 1523-1526 ◽  
Author(s):  
Yong Sheng Li ◽  
Yi Fa Sheng ◽  
Kai Yi Zhang ◽  
Bo Fan
Keyword(s):  
Magnetic Force ◽  
Short Circuit ◽  
Neutral Current ◽  
Force Balance ◽  
Analysis Method ◽  
Systematic Analysis ◽  
Negative Sequence ◽  
Transfer Equations ◽  
Zero Sequence ◽  
Negative Sequence Current

For problems of zero sequence current and negative sequence current of traction transformer in Electrified Railway, a novel balance transformer with asymmetrical windings was presented. By a systematic analysis method based on the magnetic force balance equations, winding connection equations, output-port equations and voltage transfer equations, the current relationships of the primary windings and secondary windings, the balance condition and the short circuit impedances (when the neutral current in the primary side is zero) were deduced, and the electric characteristics of the balance transformer was analyzed. Through the experimental model of balance transformer in simulation platform based on Matlab/Simulink, the electric characteristics of balance transformer and change law of zero sequence current and negative sequence current in different mode were researched. Correctness and feasibility of the theoretical analysis are verified through the simulation experiment.

scholarly journals Improving the functioning efficiency of 6-10 kV electrical networks with isolated neutral in conditions of single-phase ground faults

2021 ◽  
Vol 288 ◽  
pp. 01010
Author(s):  
Alexander Nikolaevich Kachanov ◽  
Vadim Alekseevich Chernyshov ◽  
Boris Nikolaevich Meshkov ◽  
Marsel Sharifyanovich Garifullin ◽  
Evgeny Alexandrovich Pechagin
Keyword(s):  
Single Phase ◽  
Climatic Factors ◽  
Experimental Studies ◽  
Electrical Energy ◽  
Distribution Networks ◽  
Electrical Network ◽  
Electrical Safety ◽  
Electrical Networks ◽  
Isolated Neutral ◽  
Remote Identification

The main objectives of this publication are: 1) to attract the attention of energy specialists to the problems of reliability and electrical safety of 6-10 kV overhead electrical networks with isolated neutral, operating in conditions of single-phase insulation damage; 2) substantiation of the feasibility of introducing a fundamentally new way to improve the efficiency of 6-10 kV distribution networks, based on the resonanceless limitation of the single-phase ground fault current arising from the breakdown of the insulator and the use of its own infrastructure of the electrical network for remote identification of the place of its occurrence. The expediency of including a nonlinear surge suppressor between the traverse and the grounding outlet of the reinforced concrete support is confirmed by the positive results of experimental studies carried out on the basis of high-voltage testing laboratories of IDGC of Center PJSC - Orelenergo and EnerGarant LLC. The use of deductive analysis allowed the authors to select a reliable and affordable electrical insulating material installed between the support and the traverse, as well as to formulate the main requirements for it, including taking into account weather and climatic factors. The analysis of various methods of transmitting information about the place of occurrence of the insulator damage made it possible to establish the predominant advantage of a wired communication channel using its own 6-10 kV electric network infrastructure. The authors have developed an original circuitry solution that provides remote identification of the insulator damage location using a thyristor shunting the nonlinear surge suppressor, according to a given switching algorithm, and also provides local identification of the insulator breakdown by means of special signaling devices with volatile power supply. It is expected that the proposed method, with relatively low investment, will significantly reduce the level of accidents and electrical hazards in overhead distribution networks of 6-10 kV, as well as minimize the costs associated with their operation and undersupply of electrical energy.

scholarly journals Research on a Faulty Line Selection Method Based on the Zero-Sequence Disturbance Power of Resonant Grounded Distribution Networks

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 846 ◽  
Author(s):  
Wenquan Shao ◽  
Jie Bai ◽  
Yuan Cheng ◽  
Zhihua Zhang ◽  
Ning Li
Keyword(s):  
Single Phase ◽  
Distribution Networks ◽  
Selection Method ◽  
Test Results ◽  
Simulation Test ◽  
Power Characteristics ◽  
Zero Sequence ◽  
Line Selection ◽  
The Difference ◽  
Dc Component

For fast and accurate faulty line selection (FLS) in single phase-to-ground (SPG) faults for resonant grounded distribution networks (RGDNs), this paper proposes a FLS method based on zero-sequence power characteristics. Through analysis of the zero-sequence current of SPG faults, it is found that the transient zero-sequence current in the faulty line contains abundant attenuated DC components, while that in the sound line is weak, which could be utilized as a technically practical way of judging faulty lines. Thus a FLS scheme using a transient zero-sequence DC component energy integral is put forward, which highlights the difference of the DC components in the faulty line and the sound line. A series of simulation test results indicate that the proposed scheme shows favorable performance under various SPG fault conditions, and should be helpful to improve the success rate of FLS significantly for RGDN in the future.

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