Comparison of Backflashover performance between a novel composite pylon and metallic towers

Transient Lightning Impulse Performance Analysis of a Fully Composite Pylon with an External-grounding Down-lead

“…Simultaneous flashover highly probably happens and lead to catastrophic consequences, only if the lightning current is really huge. For composite pylon, only the phase conductor in the same circuit with the hit shield wire is faced with higher BF probability, whereas the other circuit has a negligible risk to occur BF [117]. In summary, compared with traditional steel lattice towers, OHLs supported by composite pylons do not suffer from simultaneous BF of double circuits.…”

“…Overvoltage waveforms in the other circuit are shown as black curves. It can be found that the overvoltages of both circuits on steel lattice towers are of closely high amplitudes [117]. However, the overvoltage in circuit 1 on composite pylon is quite high while the overvoltage in circuit 2 is of lower amplitude [117].…”

“…The BF probability of all six cases are computed and summarized in following Table 5.3. For steel lattice towers, although lightning strokes hit only one of shield wires, both circuits are probable to occur BF at the same moment [117]. To be noted, the simultaneous flashover may be overstated in simulation than in reality because flashover simulation mainly focuses on voltage rather than energy.…”

“…The configuration and dimensions of compsoite pylon and two steel lattice towers (not in real relative scale). Source: J2 [117] Looking into the fundamental engineering application for the revolutionary composite pylon, the BF performance is compared to two traditional steel lattice towers that have been erected in Denmark at present, namely Donau tower and Eagle tower. In this research from J2, FDI model is adopted as the tower footing model for all three towers.…”

“…The soil is characterized by resistivity of 100 Ω•m and 1000 Ω•m for upper and lower layer respectively. The relative electric permittivity is set as 10 [117]. Down-leads on composite pylons are simulated by the constant surge impedance model without considering corona effect.…”