Impacts of Water-Tree Fault on Ferroresonance in Underground Cables

Abstract

Nowadays, more and more electrical power is being distributed to customers by underground cables rather than overhead transmission lines due to their advantage of providing better protection in inclement weather. They also have significantly reduced electromagnetic field emission because of their copper shielding. But underground cables have larger capacitance than transmission lines per unit. Thus, ferroresonance is more likely to occur in distribution systems using underground cables. Moreover, soil humidity at a depth of one meter remains 100 percent for most of the year, a factor that risks the occurrence of water tree (WT) in cables. Consequently, both ferroresonance and WT are prone to occur in underground cable systems. The objective of this paper is to determine the relationship between ferroresonance and water tree. A test system was designed to simulate and analyze ferroresonance in a cable system caused by single-phase switch and water tree. Eight scenarios of water tree were compared in the simulation. There sponses of ferroresonance are presented in this paper and two common patterns are observed from the simulation results.

Effective parameters of dielectric absorption of polymeric insulation with semiconductor coatings of power high voltage cables

“…With the introduction of modern high-voltage cable systems, there is, first, the possibility of widespread use of an extensive distributed cable network for data transmission of large volumes [4,5]. Secondly, the diagnosis of insulation to identify signs of its degradation, which are most pronounced in the high frequency range [6][7][8][9][10][11][12].…”

Magnetic Force Simulation of Cables in Microgrid during Faults

“…Several published papers have studied underground cables [1]- [6], but they are focused on the steady-state analysis. Few papers are focused on the magnetic field simulation [7] [8] [9]. But no paper is simulating the magnetic forces during capacitor switching and different types of faults.…”