scholarly journals OVERVOLTAGE DURING ARC SINGLE-PHASE EARTH FAILURES IN 35 KV ELECTRICAL NETWORKS

2021 ◽  
Vol 2021 (60) ◽  
pp. 38-43
Author(s):  
M.S. Seheda ◽  
◽  
O.M. Ravlyk ◽  
Z.M. Bakhor ◽  
A.Ya. Yatseyko ◽  
...  
Keyword(s):  
Computer Simulations ◽  
Single Phase ◽  
Electrical Network ◽  
Electrical Networks ◽  
Cable Line ◽  
Electric Network ◽  
Earth Fault ◽  
Isolated Neutral

The results of the study of overvoltages during arc single-phase earth faults of intermittent nature in the 35 kV electric network with isolated neutral are presented. Computer simulations of transients in the electrical network have obtained the maximum multiplicities of overvoltages at the point of occurrence of single-phase arc earth faults, which exceed theoretically expected according to known theories of the occurrence and development of overvoltages. The change of the overvoltage level on the 35 kV busbars of the network substations, electrically connected to the place of occurrence of the single-phase earth fault, and the influence of the cable line on the overvoltage multiplicity are shown. Ref. 12, fig. 3, table.

Practical Implementation of the System of Feeder Diagnostics of Single-Phase Earth Faults with Online Distributed Data Collection

2021 ◽  
Vol 64 (2) ◽  
pp. 78-85
Author(s):  
Alexander Fedotov ◽  
◽  
Rafik Basyrov ◽  
Georgii Vagapov ◽  
Ainur Abdullazyanov ◽  
...  
Keyword(s):  
Single Phase ◽  
Practical Implementation ◽  
Distributed Data ◽  
Electrical Networks ◽  
Earth Fault ◽  
Parameters Selection ◽  
Power Substation ◽  
Isolated Neutral ◽  
Ongoing Monitoring

Single-phase earth faults are one of the main problem of the distribution electrical networks with voltage 6 - 35 kV with isolated neutral. Single-phase earth fault is one of the reasons decrease of the power quality and the reliability of power supply. The paper presents the theoretical base of the monitoring parameters selection during the single-phase earth fault process and its practical implementation as an installed system at a power substation with a 110/10 kV level voltage. The hardware part of the feeder monitoring system allows implementing the determination of feeder with fault and the phase of this feeder with fault without the need to switch off of the feeders. The software part of the system allows for ongoing monitoring of feeders with built-in alarm and viewing the event archive on the supervisor computer.

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 of the possibility of application of the superposition method for implementation of algorithms for determining damage locations in networks with isolated neutral

2020 ◽  
Vol 216 ◽  
pp. 01033
Author(s):  
A.L. Kulikov ◽  
V.Ju Osokin ◽  
D.I. Bezdushniy ◽  
A.A. Loskutov
Keyword(s):  
Simulation Modeling ◽  
Fault Location ◽  
Single Phase ◽  
Superposition Method ◽  
Electrical Networks ◽  
Medium Voltage ◽  
Arbitrary Configuration ◽  
Isolated Neutral ◽  
Technical Solutions ◽  
Emergency Mode

It is difficult to develop precise algorithms for determining fault locations for single-phase and double earth faults due to the features of emergency modes in medium voltage networks of 6-35 kV. The arbitrary configuration of electrical networks complicates the development of universal fault locations algorithms and, as a rule, technical solutions are limited by the need to use one-way measurements of emergency mode parameters. The article discusses new topology independent fault location algorithms that involve the use of the superposition method. The application of the proposed algorithms is justified by the results of simulation modeling and will allow implementation of calculating the distance to the fault in networks with isolated neutral with high accuracy.

scholarly journals IMPROVEMENT METHODS AND MEANS OF FLEARER EVALUATION WHEN USING LIGHT SOURCES WITH DIFFERENT SENSITIVITY TO VOLTAGE FLUCTUATIONS IN THE ELECTRICAL NETWORK

2018 ◽  
Vol 20 (5-6) ◽  
pp. 55-66
Author(s):  
K. E. Lisitskiy
Keyword(s):  
Frequency Characteristics ◽  
Electrical Network ◽  
Light Sources ◽  
Electrical Networks ◽  
Voltage Fluctuations ◽  
Standard Methods ◽  
Electric Network ◽  
Normalized Frequency

The article considers the problem of reliable evaluation of flicker in electrical networks. The technique for calculating the normalized frequency characteristics of the instrument for light sources with different sensitivity to voltage fluctuations is presented, which is aimed at improving the standard methods for estimating the flicker. A technique for the normalization of the flicker is described on the basis of the data of the estimated estimation of the voltage fluctuations in the electric network. 

Investigation of dependences of selectivity of devices of protection against the value of short circuit currents in electrical networks up to 1000 V

2021 ◽  
pp. 98-100
Author(s):  
I. Radko ◽  
◽  
V. Nalivayko ◽  
O. Okushko ◽  
I. Bolbot ◽  
...  
Keyword(s):  
Single Phase ◽  
Modular Design ◽  
Short Circuit ◽  
Electrical Network ◽  
Electrical Networks ◽  
Circuit Breakers ◽  
New Energy ◽  
Short Circuits ◽  
Pole Scheme ◽  
Short Circuit Currents

According to PUE-2017, each group line must be protected against short circuits. Instant disconnection (cut-off) of the line in the event of short circuits provides an electromagnetic release of the circuit breaker. Reliable tripping is possible if the current of a single-phase short circuit is greater than the instantaneous tripping current. Today on the market are widely available circuit breakers with characteristics "B", "C" and "D", which are characterized by different multiplicities of the cut-off current of the electromagnetic release. Some European companies produce circuit breakers with other characteristics, which greatly expands the possibilities protection of electrical equipment. The difficulty in organizing the selectivity of protection is that the circuit breakers of modular design when switching off short circuits are characterized by the same switching time (not more than 0.05 s). The purpose of the research is to find ways to organize the selectivity of protection in electrical networks with voltage up to 1000 V using reliable values of short-circuit currents. In networks with a voltage of up to 1000 V, the current of a single-phase short circuit can be calculated fairly accurately if the exact values of all sections of the electrical network are known. In practice, it is not always possible to obtain reliable data on the numerical characteristics of the 0.4 kV network to which a new energy facility is connected. Therefore, it is proposed to consider part of the network as an active quadrupole, the characteristics of which are obtained by measurements at the point of connection. For further calculations it is necessary to know the voltage at the clamps of the four-pole scheme and the internal impedance. Based on the theory of four-pole scheme, you can get the original data for calculations without calculating the internal parameters of four-poles scheme. Thus, it is proposed to use a hybrid method for estimating the magnitude of probable short-circuit currents in electrical networks up to 1000 V when designing new energy facilities. Credible values of short-circuit currents will allow to organize selective protection of electric networks.

scholarly journals Analysis of the Influence of the Insulation Parameters of Medium Voltage Electrical Networks and of the Petersen Coil on the Single-Phase-to-Ground Fault Current

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1330
Author(s):  
Dumitru Toader ◽  
Marian Greconici ◽  
Daniela Vesa ◽  
Maria Vintan ◽  
Claudiu Solea
Keyword(s):  
Fault Location ◽  
Single Phase ◽  
Analytical Calculation ◽  
Electrical Network ◽  
Fault Current ◽  
Electrical Networks ◽  
Medium Voltage ◽  
Ground Fault ◽  
Fault Currents ◽  
Petersen Coil

Settings of protection are essential to ensure the sensitivity and selectivity needed to detect defects. Making the correct settings requires the calculation of the fault currents with as little error as possible. Fault currents are influenced by the parameters of the electrical networks, including the state of the insulation and the Petersen coil, which changes during their operation electrical networks. This paper analyzes how the insulation parameters of medium voltage power lines, the parameters of the Petersen coil used to treat the neutral of the medium voltage electrical network and the value of the resistance at the fault location influence the fault current in the case of a single-phase fault. The large number of single-phase faults that occur in medium voltage electrical networks justifies this analysis. The symmetrical components method was used to calculate the fault current. The results obtained by calculation were verified experimentally by causing a single-phase-to-ground fault in a real medium voltage network. The paper presents the situations in which the analytical calculation of the single-phase-to-ground fault current can lead to inadmissibly large errors, even over 50%, but also the situations in which the errors fall below 3%.

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.

scholarly journals Method of accounting the dynamics of technological connections when forming a list of objects for the reconstruction and construction of electrical networks

2020 ◽  
Vol 178 ◽  
pp. 01030
Author(s):  
A.V. Vinogradov ◽  
V.E. Bolshev ◽  
A.V. Vinogradova ◽  
A.A. Lansberg ◽  
M.O. Ward ◽  
...  
Keyword(s):  
Electrical Network ◽  
Monitoring Systems ◽  
Electrical Networks ◽  
Electric Network ◽  
Operating Modes

The paper gives a method of accounting the dynamics of technological connections when forming a list of objects for the reconstruction and construction of electrical networks. The specified method allows maintaining a database of technological connections taking into account the information received from the monitoring systems for electric network operating modes. It makes it possible to assess the dynamics of technological connections by settlements and regions. Based on this, it allows determining the availability of a power reserve for new technological connections and pre-compile a list of objects for reconstruction and construction of electrical network taking into account the dynamics of technological connections.

scholarly journals PROTECTION OF A TWO-CABLE LINE FROM SINGLE PHASE-TO-EARTH FAULT WITH ABSOLUTE SELECTIVITY

2018 ◽  
Vol 431 (5) ◽  
pp. 128-132
Author(s):  
Zh. Issabekov ◽  
A. N. Novozhilov ◽  
T. A. Novozhilov ◽  
B. B. Issabekova
Keyword(s):  
Single Phase ◽  
Cable Line ◽  
Earth Fault
Sign in / Sign up

Export Citation Format

Share Document