Recently, the National Quality Inspection Department supervised the sampling and inspection of power transformers, and the sampling pass rate was only 69.0%.
It is reported that a total of 34 enterprises in the production fields of 16 provinces (municipalities) have been spot-checked, except that 4 enterprises have no finished products, and 1 is still under review and rectification due to unsatisfactory spot checks last year, and a total of 29 units of 29 companies have been spotted. product. Among them, 20 products were qualified and 9 products failed.
Among them, only one company was sampled in Sichuan Province, and the product qualification rate was 0.0%. The product qualification rates of Shanghai, Jiangsu, Anhui, Shandong, Henan, Hubei, and Hunan were all 50.0%. The qualified rate of products in Hebei Province was 66.7%. The qualification rate of the remaining 7 provinces and cities was 100%.
The spot checks of large, medium, and small-sized enterprises did not differ greatly. The pass rate of sampling for large enterprises was 75.0%, and the sampling pass rates for small and medium-sized enterprises were 63.6% and 71.4%, respectively.
The prominent data of partial discharge problems show that the number of unqualified samples in the temperature rise test is the highest (20.7%) in the inspection items (excluding inspection items). Among them, 4 sets are the temperature rise of the winding exceeds the national standard limit. Among these 4 samples, only one has no-load loss exceeding the standard, and the remaining 3 sets of no-load loss, load loss, and total loss do not exceed the standard requirement value, and the rest 2 After one of Taichung was tested for no-load current and no-load loss after the insulation test, the sample failed and the test could not be performed, resulting in no-load current and no-load loss measurement, short-circuit impedance and load loss measurement, and temperature rise test 3 The items failed.
The other one failed to install seals on the top of the high-pressure A-phase casing. As a result, during the temperature rise test, the high-pressure A-phase casing leaked oil and the test could not be carried out. Therefore, the test failed. As the samples that have been sampled are complete products that have been inspected and allowed to be sold by the company, the occurrence of missing seals has occurred, which indicates that the company's quality management, product technology, and factory inspection control have major defects.
The item with a high rate of disqualification in the supervision and spot check is partial discharge measurement, with a failure rate of 28.6%. Partial discharge measurement was only performed on a dry type power transformer. A total of 7 dry power transformers were sampled this time, and the partial discharges of 2 samples exceeded the standard limits.
There are 3 samples in this surveillance spot check because the no-load current or no-load loss exceeds the standard, resulting in unqualified measurement items of no-load current and no-load loss, and the failure rate is 10.3%. Among these three samples, one was not qualified because the no-load current exceeded the specified value of the company's product. As described above, after the insulation test, the sample failed and the test failed. . One is because the no-load loss exceeds the standard, and the temperature rise test of this sample is also unqualified, which indicates that the abnormal heating and the temperature rise of the product is too high.
In this supervision and spot check, one sample was short-circuit impedance and load loss measurement items failed, and its failure rate was 3.4%. The highest number of unqualified nameplates and signs was checked, and the failure rate was 27.6%.
Comparing the number of sampling samples from 2009 to 2010, the number of samples taken from these inspections was the same, and the three qualified rates were relatively close to each other, which ranged from 70% to 80%. It can be seen that the qualified rate of power transformer national supervision and inspection is not High, this year's pass rate has also dropped significantly. This is due to the fact that nearly three years of national supervision and spot checks for power transformers have been mainly targeted at small and medium-capacity power transformers with a voltage rating of 10kV. These production companies mainly belong to small and medium-sized enterprises. The number of enterprises that are spot-checked each time is only a small part of the total number of companies in the country, which shows that the quality of medium- and small-capacity power transformers in domestic small and medium enterprises is more prominent.
It is reported that a total of 34 enterprises in the production fields of 16 provinces (municipalities) have been spot-checked, except that 4 enterprises have no finished products, and 1 is still under review and rectification due to unsatisfactory spot checks last year, and a total of 29 units of 29 companies have been spotted. product. Among them, 20 products were qualified and 9 products failed.
Among them, only one company was sampled in Sichuan Province, and the product qualification rate was 0.0%. The product qualification rates of Shanghai, Jiangsu, Anhui, Shandong, Henan, Hubei, and Hunan were all 50.0%. The qualified rate of products in Hebei Province was 66.7%. The qualification rate of the remaining 7 provinces and cities was 100%.
The spot checks of large, medium, and small-sized enterprises did not differ greatly. The pass rate of sampling for large enterprises was 75.0%, and the sampling pass rates for small and medium-sized enterprises were 63.6% and 71.4%, respectively.
The prominent data of partial discharge problems show that the number of unqualified samples in the temperature rise test is the highest (20.7%) in the inspection items (excluding inspection items). Among them, 4 sets are the temperature rise of the winding exceeds the national standard limit. Among these 4 samples, only one has no-load loss exceeding the standard, and the remaining 3 sets of no-load loss, load loss, and total loss do not exceed the standard requirement value, and the rest 2 After one of Taichung was tested for no-load current and no-load loss after the insulation test, the sample failed and the test could not be performed, resulting in no-load current and no-load loss measurement, short-circuit impedance and load loss measurement, and temperature rise test 3 The items failed.
The other one failed to install seals on the top of the high-pressure A-phase casing. As a result, during the temperature rise test, the high-pressure A-phase casing leaked oil and the test could not be carried out. Therefore, the test failed. As the samples that have been sampled are complete products that have been inspected and allowed to be sold by the company, the occurrence of missing seals has occurred, which indicates that the company's quality management, product technology, and factory inspection control have major defects.
The item with a high rate of disqualification in the supervision and spot check is partial discharge measurement, with a failure rate of 28.6%. Partial discharge measurement was only performed on a dry type power transformer. A total of 7 dry power transformers were sampled this time, and the partial discharges of 2 samples exceeded the standard limits.
There are 3 samples in this surveillance spot check because the no-load current or no-load loss exceeds the standard, resulting in unqualified measurement items of no-load current and no-load loss, and the failure rate is 10.3%. Among these three samples, one was not qualified because the no-load current exceeded the specified value of the company's product. As described above, after the insulation test, the sample failed and the test failed. . One is because the no-load loss exceeds the standard, and the temperature rise test of this sample is also unqualified, which indicates that the abnormal heating and the temperature rise of the product is too high.
In this supervision and spot check, one sample was short-circuit impedance and load loss measurement items failed, and its failure rate was 3.4%. The highest number of unqualified nameplates and signs was checked, and the failure rate was 27.6%.
Comparing the number of sampling samples from 2009 to 2010, the number of samples taken from these inspections was the same, and the three qualified rates were relatively close to each other, which ranged from 70% to 80%. It can be seen that the qualified rate of power transformer national supervision and inspection is not High, this year's pass rate has also dropped significantly. This is due to the fact that nearly three years of national supervision and spot checks for power transformers have been mainly targeted at small and medium-capacity power transformers with a voltage rating of 10kV. These production companies mainly belong to small and medium-sized enterprises. The number of enterprises that are spot-checked each time is only a small part of the total number of companies in the country, which shows that the quality of medium- and small-capacity power transformers in domestic small and medium enterprises is more prominent.
Kingunion Lighting Co., Ltd. , http://www.sz-ledlight.com