采用4种不同纵磁触头结构的126 kV单断口真空断路器温升性能对比研究

For improving rated current flow capacity of 126 kV single-break vacuum circuit breaker(VCBs)further, the temperature rise feature of 126 kV vacuum circuit breaker adopting 4 kinds of different AMF contact structures is compared and studied in this paper. The 4 kinds of AMF contacts are 2/3 turn coil-type AMF contact, 3/4 turn coil-type AMF contact, horseshoe-type AMF contact and slotted horseshoe-type AMF contact, respectively. The finite element simulation result shows that, in case of flowing current at 3 150 A, the hot state AC resistances for the 4 kinds of AMF contacts are 30.2, 36.9, 24.0 and 16.3 μΩ, respectively. Temperature distribution of the 4 kinds of VCBs is obtained by employing finite volume method. Temperature-rise simulation models are verified by experimental results at flowing current at 2 500 A. It is shown by the result that the calculation errors of the simulation model within 5 temperature measurement points around interrupter is less than 10%, the maximum calculation error of 36% is on the terminal of circuit breaker since the influence of external wiring is not considered. It is found through simulation of temperature rise feature of 4 kinds of AMF contacts at 3 150 A that the slotted horseshoe-type AMF contact has the best temperature-rise performance among above 4 kinds of contact structures and its temperature rise performance at nominal rated current of 3 150 A complies with China National Standard(GB) requirement, in which the temperature rise at the highest temperature measurement point is 66 K.