电缆橡胶绝缘层热延伸试验的测量不确定度评定

Uncertainty Evaluation on Measurement of Hot Set Test of Rubber Insulation of Cables

依据GB/T 2951.21-2008对电缆橡胶绝缘层进行了热延伸试验,并对其试验结果的不确定度进行了评定。结果表明:影响橡胶绝缘层热延伸试验结果的主要因素为橡胶绝缘层伸长量的测量,试验拉应力、烘箱温度以及试验室环境温度等对试验结果也有一定的影响。试验橡胶绝缘层的热延伸试验结果为:高温负载下伸长率y=15%,其扩展不确定度U=4.2%(包含因子k=2);卸载冷却后永久伸长率y'=5%,其扩展不确定度U=4.4%(k=2)。

According to GB/T 2951.21-2008,hot set test of a cable rubber insulation was carried out,and the uncertainty of the test results was evaluated. The results show that the main factor affecting the hot set test results is the measurement of the elongation of the rubber insulation. The tensile stress,oven temperature and laboratory ambient temperature also have certain influence on the test results. The hot set test results of the test rubber insulation are as follows： the percentage elongation under high temperature and loading condition y = 15% with the expanded uncertainty U =4.2% when the including factor k = 2; the permanent percentage elongation after unloading and cooling y＇ = 5% with the expanded uncertainty U = 4.4% when k = 2.