Electrostatic Simulation of a Medium Voltage Cable; Effects of a Void Defect
CASES SOLVED WITH CHARGE
Electric power cables are utilized for power transmission in cases where the installation of overhead lines is either impractical or undesirable, for example in urban areas.
In addition to underground cables, submarine power cables may be used for interconnections between coastal regions.
Cables are significantly more expensive than overhead lines, due to the additional cost of insulation.
Electric power cables are utilized for power transmission in cases where the installation of overhead lines is either impractical or undesirable, for example in urban areas. In addition to underground cables, submarine power cables may be used for interconnections between coastal regions.
Cables are significantly more expensive than overhead lines, due to the additional cost of insulation.
Innovative designs which incorporate new materials are constantly introduced to improve cable performance. Electrostatic simulation has been regularly used as a tool by cable designing engineers, to provide valuable data about electric potential and electric field strength.
Conclusions
A typical medium voltage cable has been simulated using Charge 3.0 to estimate the electric potential and field values; the effects of a void defect inside the cable have also been investigated.
Accurate estimation of electric potential and field distribution inside both a perfect cable and a flawed one was achieved, using a very dense mesh of more than a million boundary elements. Despite that, simulation time for both cases was shorter than 9 minutes.
In the case of a perfect cable, highest values of the electric field are located at the surface of the semiconductive layer around the conductor, as could be easily visualized using the “filtering” option of Charge 3.0.
In the case of a flawed cable, the electric field strength is considerably enhanced inside the void defect, favoring thus the development of partial discharges that could gradually cause even the permanent damage of the cable.
The variation of the electric field values inside a typical MV cable is in very good agreement with theoretical results obtained based on simplifying assumptions. Such assumptions, however, result in erroneous theoretical predictions in the case of a flawed cable, where simulations are necessary for the precise investigation of the effects of void defects.