Investigation on the Thermal Performance of a 363 kV Vacuum Circuit Breaker Using a 3D Coupled Model

Abstract

Multi-break vacuum circuit breakers (VCBs) are the most potential approach for applying VCBs to high voltage power system. However, it has higher thermal stability requirements than normal single break VCBs due to its complex structure and high rated current. In this paper, a novel 363 kV/5000 A/63 kA SF 6 gas insulate (GI) VCB with series and parallel structure is proposed. To analyze its temperature rise, a 3D coupled electromagnetic-thermal-fluid model is established based on actual size and calculated by finite element method under rated condition, which enables prediction of the temperature distribution of the contacts of VCB and bus bar. In the numerical model, the vacuum chamber is modelled as solid material with temperature dependent effective thermal conductivity while skin effect, nonlinear property of conductor resistivity and turbulence model are taken into consideration. The simulation results show that the hot spot is the contacts of VCB with a temperature of 102.2 K, while the temperature of busbars reach at 92.3 K. In addition, the influences of contact resistance, short circuit current on the temperature rise are discussed. Finally, the simulation results are validated by temperature rise experiment on prototype. Using the proposed model, the temperature rise and hot spot area can be predicted in advance, which could finally facilitate the design and performance evaluation of the 363 kV GI-VCB.INDEX TERMS Vacuum circuit breaker, temperature rise, coupled model, turbulence model, contact resistance.

Numerical Study on Electromagnetic Coupled Heat Transfer and Ultrasonic Propagation in GIS Busbar Chamber

“…where v ⇀ is the velocity vector of SF6 gas, m/s; ρ (T) is the SF6 gas density, kg/m 3 ; c p (T) is the heat capacity of SF6 gas, J/(kg•K); p is the pressure, Pa; μ (T) is the dynamic viscosity of SF6 gas, kg/(m•s); μt is the turbulent viscosity of SF6 gas, kg/(m•s); β is the volumetric expansion coefficient of SF6 gas; g is the gravitational acceleration, m/ s 2 ; λ (T) is the thermal conductivity of SF6 gas, W/(m•K); σ T is the Prandtl number of SF6 gas in the heat transfer equation; k is the turbulent kinetic energy, m 2 /s 2 ; ε is the turbulent dissipation rate, m 2 /s 3 ; P k is the turbulent shear generation term, kg/(m•s 3 ); σ k and σ ε are the Prandtl numbers in the k and ε equations, respectively; and c ε1 and c ε2 are the model constants in the k and ε equations, respectively. e heat transfer on the outer surface of busbar conductor is formulated as follows [25]:…”

Effect of Magnetic Field on Different Opening Processes of Multi-Break Vacuum Gaps

“…More and more attention has been paid to multi-break vacuum circuit breaker in the aspect of breaking capacity and replacement of SF 6 switch. Due to stray capacitance, the voltage distributions of breaks in series are unbalanced [3][4][5].…”