Small Current Neutral Grounding System Research Articles

A new approach to fault-line selection of small current neutral grounding system

ABSTRACTIn this paper, a new approach combining BP neural network with fuzzy Petri net (FPN) is developed to deal with the issue of fault-line selection of the small current neutral grounding system. First, the preliminaries of the FPN are briefly introduced. Then, the model of the fault-line selection is detailedly described to explain the new feature representation that fuses multiple fault features of the lines, including the wavelet energy, the active component and the fifth harmonic component. Finally, the simulation model of the fault-line selection is constructed, and the simulation experiments are carried out to verify the effectiveness of the new approach, which could be superior to the traditional fault-line selection approaches.

The Design Based on Integrated Criterion to Faulty Line Selection for Small Current Neutral Grounding System

Small current neutral grounding system is widely used in 3~66 kV power distribution system in China. In this power system, the single-phase to-earth fault occurs frequently in distribution, thus how to detect the fault line with great accuracy and high efficiency is an important subject in protective relaying of power system. According to a variety of existing theories of fault line selection for small-current neutral grounding system, this paper presents a new design based on integrated criterion, which has been applied in actual production.

A Survey on Single-Phase Faulty Line Selection Techniques for Small Current Grounding System in Medium-Voltage Grid

Single-phase ground fault line selection problem has never been satisfactorily resolved in small current neutral grounding system in china. According to such a situation and combining theoretical analysis and simulation research with reports published in literature, existing faulty line selection technologies are generalized, and working principles, application conditions and existing defects of these technologies are analyzed, meanwhile the feasible improvement of these technologies and the up-to-date research achievements, and deficiencies of applications in this field are summarized. Finally, the development trend of faulty line selection technology for small-current neutral grounding system is pointed out.

Research on Ferroresonance Detection in Small Current Neutral Grounding System

A novel method to detect ferroresonance was proposed based on the drastic characteristics of the electromagnetic voltage transformer (PT) current rate. This scheme takes current rate which is greater than a threshold value as starting signal and judges the occurrence of resonance by detecting duty ratio of the peaks and interval angles. Then, it identifies the periods and patterns established on the interval time of spikes. Through simulation testing of MATLAB, it can distinguish the occurrence and types of ferroresonance accurately, which verifies the validity of the detection method.

A Fault Line Detection Method Based on Wavelet Packet Analysis in Distribution Network

With the rapid development of power network automation, the detection of the default single-phase grounding fault line in small current neutral grounding system has became a hot spot in research of power network system. Generally, power network neutral point is not grounded or grounded through arc-suppression coil grounding. When single phase grounding fault occurs, the power network system is named as small current grounding system since the grounding short-circuit is small due to a low-impedance short circuit.