scholarly journals Utilization of Cable Screen Earthing Current for Detection and Location of Earth Faults in Medium Voltage Networks

2021 ◽  
Vol 7 (1) ◽  
pp. 17-25
Author(s):  
Krzysztof Łowczowski ◽  
◽  
Józef Lorenc ◽  
Magdalena Czerniak ◽  
Józef Zawodniak ◽  
...  
Keyword(s):  
Simulation Research ◽  
Overhead Lines ◽  
Medium Voltage ◽  
Detection And Localization

The paper presents issues related with detection and location of earth faults in medium voltage (MV) networks. Attention is paid on cable and cable-overhead lines. The criterion value – cable screen earthing current is presented. Afterwards, the method of utilization of the cable screen earthing current for detection and location of earth faults is described. The next part of the paper presents the results of simulation research for different variants of earth faults in cable and cable-overhead lines. The presented relations are the basis of the developed algorithm of detection and localization of earth faults. The presented considerations were confirmed by an experiment performed in the MV network.

New solutions in EDP Distribuicao medium voltage overhead lines

2009 ◽  
Author(s):  
A. Cardoso ◽  
J. Cardoso ◽  
J. Figueiredo ◽  
N. Mendes
Keyword(s):  
Overhead Lines ◽  
Medium Voltage

scholarly journals Photovoltaic Maximum Penetration Limits on Medium Voltage Overhead and Underground Cable Distribution Feeders: A Comparative Study

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3843
Author(s):  
Sultan Sh. Alanzi ◽  
Rashad M. Kamel
Keyword(s):  
Power System ◽  
Power Factor ◽  
Distribution System ◽  
Power Flow ◽  
Underground Cables ◽  
Overhead Lines ◽  
Medium Voltage ◽  
Load Power ◽  
Bus Voltage ◽  
Pv Penetration

This paper investigates the maximum photovoltaic (PV) penetration limits on both overhead lines and underground cables medium voltage radial distribution system. The maximum PV penetration limit is estimated considering both bus voltage limit (1.05 p.u.) and feeder current ampacity (1 p.u.). All factors affect the max PV penetration limit are investigated in detail. Substation voltage, load percentage, load power factor, and power system frequency (50 Hz or 60 Hz) are analyzed. The maximum PV penetration limit associated with overhead lines is usually higher than the value associated with the underground cables for high substation voltage (substation voltage = 1.05 and 1.04 p.u.). The maximum PV penetration limit decreases dramatically with low load percentage for both feeder types but still the overhead lines accept PV plant higher than the underground cables. Conversely, the maximum PV penetration increases with load power factor decreasing and the overhead lines capability for hosting PV plant remains higher than the capability of the underground cables. This paper proved that the capability of the 60-Hz power system for hosting the PV plant is higher than the capability of 50 Hz power system. MATLAB software has been employed to obtain all results in this paper. The Newton-Raphson iterative method was the used method to solve the power flow of the investigated systems.

scholarly journals An Effective Method to Calculate Frequency Response of Distribution Networks for PLC Applications

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 649 ◽  
Author(s):  
Hongshan Zhao ◽  
Weitao Zhang ◽  
Yan Wang
Keyword(s):  
Frequency Response ◽  
Distribution Networks ◽  
Dynamic Changes ◽  
Binary Function ◽  
Underground Cables ◽  
Overhead Lines ◽  
Medium Voltage ◽  
Response Characteristics ◽  
Network Topologies ◽  
Propagation Matrix

Modelling and estimating power-line communication (PLC) channels are complicated issues due to the complex network topologies, various junctions, and changeable loads. This paper focuses on the frequency response characteristics (FRCs) of medium-voltage (MV) PLC networks with special consideration of two scenarios that are often neglected but generally exist. In the first scenario, the MV distribution network is of the ring topology. In the second scenario, the MV overhead lines and underground cables join at junctions, and the shields of underground cables are grounded with nonzero grounding impedances at the junctions. These conditions lead to the failure of currently popular methods to different degrees. For this reason, we developed an effective method to calculate the FRCs of distribution networks for PLC applications. With this method, the frequency responses of nodes are simply expressed as the binary function of the overall tube propagation matrix and overall node scattering matrix, which is convenient for calculations and analyses. The proposed method was validated by the agreement between the calculated and measured FRCs. The results of two test examples showed that the proposed method performed better in comparison with the traditional approximate method when nonideal grounding conditions were taken into account. The proposed method is also independent of the network topology, so it can adapt to the dynamic changes of the network structure.

Ageing of medium voltage overhead lines

2009 ◽  
Author(s):  
A. Minaud ◽  
J. Pezard ◽  
J.-P. Priam
Keyword(s):  
Overhead Lines ◽  
Medium Voltage

scholarly journals Verification of a Novel Method of Detecting Faults in Medium-Voltage Systems with Covered Conductors

2017 ◽  
Vol 24 (2) ◽  
pp. 277-288 ◽  
Author(s):  
Stanislav Mišák ◽  
Štefan Hamacek ◽  
Mikołaj Bartłomiejczyk
Keyword(s):  
Relay Protection ◽  
Overhead Lines ◽  
Medium Voltage ◽  
New Methods ◽  
Protection Systems ◽  
Novel Method ◽  
Covered Conductors ◽  
Tree Branch ◽  
New System ◽  
Three Phases

AbstractThis paper describes the use of new methods of detecting faults in medium-voltage overhead lines built of covered conductors. The methods mainly address such faults as falling of a conductor, contacting a conductor with a tree branch, or falling a tree branch across three phases of a medium-voltage conductor. These faults cannot be detected by current digital relay protection systems. Therefore, a new system that can detect the above mentioned faults was developed. After having tested its operation, the system has already been implemented to protect mediumvoltage overhead lines built of covered conductors.

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