On-site testing of high voltage cable systems after laying; voltage tests

1995 ◽  
Author(s):  
N. van Schaik
Keyword(s):  
High Voltage ◽  
Site Testing ◽  
Cable Systems

scholarly journals Amplitude Distribution of Partial Discharge Signals on Tunnel-Installed High-Voltage Cables

2019 ◽  
Vol 9 (21) ◽  
pp. 4595 ◽  
Author(s):  
Yong Qian ◽  
Xiaoxin Chen ◽  
Yiming Zang ◽  
Hui Wang ◽  
Gehao Sheng ◽  
...  
Keyword(s):  
High Voltage ◽  
Partial Discharge ◽  
Current Method ◽  
Signal Amplitude ◽  
Amplitude Distribution ◽  
Xlpe Cable ◽  
Bonding Wires ◽  
Cable Laying ◽  
Cable Systems ◽  
The Cross

For 110 kV and above tunnel-installed high-voltage (HV) cross-linked poly-ethylene (XLPE) cable systems, it is a normal procedure to adopt a cross-bonding scheme. The high-frequency current method is frequently used in the cross-bonded cable systems for on-site or online partial discharge (PD) detection by monitoring the signals on the cross-bonding wires. To further study the amplitude distribution characteristics of the PD signals, a parametric characteristic admittance model of a three-phase cable system in a tunnel is established based on Tylavsky’s formulas. The model is used to calculate the amplitude distribution formula of the PD pulse current on the cross-bonding wires. In addition, the influence of cable laying and tunnel environment on the amplitude distribution is also studied. Finally, the correctness of the model and the conclusion are verified by simulation experiments and on-site tests. The results show that the signal amplitude distribution is determined by the ratio of the characteristic admittances. As the distance between the cables and the distance from the inner wall of the tunnel increase, the amplitude difference gradually decreases.

A New Approach for Partial Discharge Modeling in High Voltage Cables Considering Nonlinear Permittivity Using Finite Element Method

2020 ◽  
Vol 12 (4) ◽  
pp. 457-463
Author(s):  
Asaad Shemshadi ◽  
Pourya Khorampour
Keyword(s):  
Finite Element ◽  
High Voltage ◽  
Partial Discharge ◽  
Nonlinear Function ◽  
New Approach ◽  
Novel Technique ◽  
Remote Assessment ◽  
Cable Systems ◽  
Discharge Modeling ◽  
Simple Modeling

Herein, we report a novel technique to develop remote assessment and observation for partial discharge events under high voltage cable systems output. Finite element modeling of the cavities bided in the insulators which are the source of Partial Discharge signals occurred in a 3-d section of a typical 230 KV high voltage XLPE 3-phase cable. All electromagnetic related equations are solved using FEM software. The idea is to consider the permittivity constant in cavities as a nonlinear function during the solving process. This function is related to electric field value inside each cavity. This modeling leads to a new approach in simple modeling of PD phenomena in the H. V. apparatus with the big amount of destructive PD cavities. In continue, the obtained waveform is illustrated respecting to the main power line waveform.

Modeling the electric field at interfaces and surfaces in high-voltage cable systems

2020 ◽  
Vol 39 (5) ◽  
pp. 1099-1111 ◽  
Author(s):  
Christoph Jörgens ◽  
Markus Clemens
Keyword(s):  
Electric Field ◽  
Electric Conductivity ◽  
High Voltage ◽  
Analytic Description ◽  
Time Varying ◽  
Content Type ◽  
Field Stress ◽  
Space Charges ◽  
Stationary Electric Field ◽  
Cable Systems

Purpose In high-voltage direct current (HVDC) cable systems, space charges accumulate because of the constant applied voltage and the nonlinear electric conductivity of the insulating material. The change in the charge distribution results in a slowly time-varying electric field. Space charges accumulate within the insulation bulk and at interfaces. With an operation time of several years of HVDC systems, typically the stationary electric field is of interest. The purpose of this study is to investigate the influence of interfaces on the stationary electric field stress and space charge density. Design/methodology/approach An analytic description of the stationary electric field inside cable insulation is developed and numerical simulations of a cable joint geometry are applied, considering spatial variations of the conductivity in the vicinity of the electrodes and interfaces. Findings With increasing conductivity values toward the electrodes, the resulting field stress decreases, whereas a decreasing conductivity results in an increasing electric field. The increased electric field may cause partial discharge, resulting in accelerated aging of the insulation material. Thus, interfaces and surfaces are characterized as critical areas for the reliability of HVDC cable systems. Research limitations/implications This study is restricted to stationary electric field and temperature distributions. The electric field variations during a polarity reversal or a time-varying temperature may result in an increased electric conductivity and electric field at interfaces and surfaces. Originality/value An analytical description of the electric field, considering surface effects, is developed. The used conductivity model is applicable for cable and cable-joint insulations, where homo- and hetero-charge effects are simulated. These simulations compare well against measurements.

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