1.3 Type test
The type test is mainly to determine whether the design of the cable product is Whether it meets the expected use requirements. Generally, it is a one-time test, and it is mostly destructive, including electrical performance, physical performance of the mechanism and various specific requirements. The test to verify whether the product can meet all the requirements of the technical specifications is an indispensable part of the new product appraisal. Only through the type test can the product be officially put into production.
- a The partial discharge test is measured on a short cable sample. The test standard is the same as the routine test.
- b. Bend test plus partial discharge test. In the exaggerated bending test, the bending multiple of the cable is: single-core cable: 20(D+d); three-core cable: 15(D+d)±5% where D and d are the outer diameters of the cable and conductor, respectively, and the bending test After testing the partial discharge of the cable, the result should meet the requirements of the routine test.
- c. Dielectric loss and capacitance test. Capacitance value when measuring U0
- d. Partial discharge test after heating cycle. 35kV and below cable to carry out this test, the specific method is to heat the cable to
Working temperature plus 10℃ for 2h, natural cooling for 4h, so cycle 3 times; the measurement of partial discharge shall meet the requirements of routine test.
- e. Impulse voltage test and AC voltage test; heat the cable to the highest working temperature plus 5℃: perform impulse voltage test according to Table 4
After 10 times of positive and negative polarity, the main insulation of the cable should not be broken down; after the impulse voltage test, the main insulation of the cable should not be broken down after applying the working voltage at room temperature for 15 minutes. The value is the same as the routine test.
- f. The 4 h AC voltage test is the same as the sampling test value.
- g. Accelerated aging test. For 35kV and above cables
Accelerated aging test (in line with cycle test). The test condition is
Apply AC voltage to the cable to 2U0 for 20d.
1.4 Pre-qualification test
With the widespread use of cross-linked cables, especially high-voltage cables and ultra-high-voltage cables, in order to ensure and verify the relevant performance of cross-linked cables, especially the various performances and effects in operation are confirmed in time, an assessment is proposed to determine cross-linking Pre-qualification test verification system for cable performance and corresponding EC standards. The pre-qualification test requires that the finished cable and accessories must pass this test before the qualification can be carried out.
The main content of the pre-qualification test is to apply 1.7 times the rated operating voltage to the entire cable test line including various accessories on a cable of about 100m. The test voltage is maintained at 1a. At the same time, the current is increased to make the conductor work, and the temperature reaches the rated temperature and remains positive. The deviation is 0~5℃, and then it is cooled to the ambient temperature, and a total of not less than 180 cycles of cooling and heating are carried out. In this high field
After the intense thermal cycle test is completed, the operating impulse voltage test and the lightning impulse voltage test are carried out on the entire cable test circuit, and the partial discharge performance should be monitored if possible.