State General Administration of Quality Supervision spot-check the quality of dry type power transformers in Beijing, Tianjin, Hebei, Liaoning, Jilin, Heilongjiang, Shandong, Henan, Hunan, Hubei, Shaanxi, Jiangsu, Zhejiang, Shanghai, Sichuan, Guangdong, Fujian, Gansu, and Chongqing 19 provinces, municipalities. 50 products of 49 enterprises, 39 kinds are qualified and about 78% passing rate.

the results shows that the insulation level of dry type transformer is high. And all the products meet national standard in the pressure standard test and pressure sensors test, and 61.2% products' pressure resistance is better than national standard and the loss is also lower than national standard. SC9 series of low loss dry power transformer is the main products in China, yet as the demand of market, the production of SC10 increase. Among the 50 sampling products there are 3 kinds of SC8 products, 39 kinds of SC9 products, 8 kinds of SC10 products. The SCB9-1000/10 dry-type transformercan save 5000 electricity than that of SC8-100/10 a year. The noise problem has got much attention. the products of 34 enterprises among the 49 enterprises's noise level is lower than the national standard of 5-20db 34 enterprise.

The checks also found a number of product quality issues：
　　1.great difference of partial discharge. PD refers to that the weak insultion place discharge when the products under a certain external pressure. There are about 6 kinds of products has high partial discharge for unstable manufacturing process, and unstable material performance.
　　2.some products do not models registered. At present, some enterprises do not pay much attention to the importance of model registration. There are about 24 products of 24 enterprises are in production without register the models.
　　3.insufficient attention to type testing and special testing.The type testing of dry-type power transfomer includes temperature rise test, lighting impact test. And the sprcial test includes short-circuit tolerance test and sound-level determination. The type testing and the special are the iindispensable test for the new products according to the national standard. Only through these test can sure whether the product design, techonology and mamufacturing meet the standard and can ensure the reliable and safe operation. There are about 22 enterprises' products does not have the type test and the special test. The products is very easily lead to quality problems if the products have not been certified.

The AQSIQ is in charge of local quality technical supervision departments according to the spot-check results. It punish the disqualification enterprises and also will announce a number of qualification enterprises. AQSIQ will continue to spot-check the series products to promote the high quality of dry-type power transformer products.