Zhiwei Electric Power Technology Co.,Ltd
China has become a production base for household appliances and electrical and electronic products, and exports are increasing. Together with product safety for consumers, manufacturers are constantly improving product safety standards in accordance with relevant global laws and regulations. In addition, manufacturers also pay a lot of attention to the safety inspection of products before they leave the factory. At the same time, the safety of the electrical function of the product, or perhaps the safety against electric shock, is also a very important item to check.
In order to understand the insulation function of a product, there are specifications or datasheets for product planning, construction, and insulation materials. Usually, manufacturers use different methods to check or test them. However, for electrical products, one type of test that is mandatory is the dielectric resistance test, which is sometimes referred to as voltage withstand test or withstand voltage test, high voltage test, electrical strength test, etc. The general insulation function of the product is good or bad; it can be reflected by the electrical strength test. The high-voltage withstand voltage test of electrical equipment is one of the most important items stipulated in the Insulation Preventive Test, and the withstand voltage test can be divided into AC withstand voltage test and DC withstand voltage test.
In the past in the cable voltage withstand test are used in DC voltage withstand test. After research and practice shows that: DC withstand voltage test on rubber and plastic insulation is invalid and harmful. China in the nineties began to study and practice the AC withstand voltage test technology. Domestic and foreign standards bodies have also made changes and revisions to the test methods of high-voltage cables. 1997 May CIGRI International Power Grid Work Conference on the current use of DC withstand voltage test method to put forward the doubt, and recommended the use of frequency and approximate frequency (30-300HZ) of the AC test method, to promote the application of the world. In the relatively developed provinces of China’s power grid, AC withstand voltage test has become a mandatory standard. Test protocols for other regions are also being drafted and in the pipeline. AC withstand voltage test to replace the traditional DC withstand voltage test has been the general trend.
AC withstand voltage test can be divided into industrial frequency, variable frequency and 0.1Hz ultra-low frequency test technology, of which 0.1Hz ultra-low frequency technology is the latest technology, which is currently recommended by the International Electrotechnical Commission. According to the actual situation of China’s electric power system, the National Development and Reform Commission has formulated the standard of “0.1Hz ultra-low frequency test method for cross-linked polyethylene insulated power cables up to 35kV”, and the power industry standard of “general technical conditions of ultra-low frequency high-voltage generator DL/T 849.4-2004” was issued in 2004, and our country is promoting this latest test method. test method.
Industrial Frequency Withstand Voltage Test Equipment:
Industrial frequency withstand voltage test device it is a power station, power supply and distribution system and scientific research units and other users of the basic test equipment. Used for various electrical products, electrical equipment, insulating materials, such as insulation strength test under the specified voltage, assessment of the insulation level of the product, to find the insulation defects of the test article, measure the ability to withstand overvoltage. It is the necessary equipment for power supply enterprises, large factories, metallurgy, power plants, railways and other power maintenance departments.
Insulation strength test for various electrical products, electrical equipment, insulating materials, etc. under the specified voltage.
Reference standard: GB 50150-2016, GB/T 8218-1987, DL/T 474.4-2018
Input voltage: 220/380v
Output Voltage:50kV-250kV
Variable frequency resonant test set:
Frequency series resonance test set is suitable for large-capacity, high-voltage capacitive test piece of handover and preventive testing, mainly for 6kV ~ 500kV cable, power transformers, GIS, switches, buses, bushings, transformers and other substation capacitive equipment. Series resonance test set is suitable for the following test items:
1, 6kV ~ 500kV high-voltage crosslinked cable AC voltage test
2, AC voltage test of generator
3, GIS and SF6 switch AC voltage test
4, 6kV ~ 500kV transformer AC voltage test
5, other electric power high-voltage equipment, such as busbar, bushing, transformer AC voltage test
This device is mainly used for AC voltage withstand test of cross-linked cable, hydro generator, main transformer, busbar, GIS, etc. It is an ideal voltage withstand equipment for electric power installation and repair engineering units. The device is mainly composed of frequency control power supply, excitation transformer, reactor and capacitor voltage divider.
In order to purchase the appropriate series resonance equipment, the following technical parameters need to be provided:
1, power transformer: voltage level (such as 10/35/110/220kV specifications, etc.) Maximum capacity: the nature of the test (neutral withstand voltage or full insulation withstand voltage) single-phase to ground capacitance
2, power cables: voltage level (10/35/110kV specifications, etc.), the maximum length, the cross-sectional area
3, generators, Motor: voltage level (export voltage or said working voltage) test voltage (maximum withstand voltage value) single-phase ground capacitance range (e.g., 0.2 ~ 0.55μF)
4, GIS: voltage level (or said working voltage); test voltage (maximum withstand voltage value) number of intervals
5, switches, insulators, PTs, CTs, insulator apparatus, busbar, voltage level (or working voltage), test voltage (maximum CVT calibration: voltage level (or working voltage such as 35/110/220 specifications, etc.), test voltage (zui high withstand voltage value), capacitance range (e.g., 0.005 ~ 0.02μF, etc.)
In the large and medium-sized generators, motors, power cables and other specimens for the frequency withstand voltage test, because of their insulation layer presents a large electric capacity, so it requires a large capacity of the test transformer or resonant transformer. These huge equipment, not only bulky, high cost, and very inconvenient to use. In order to solve this contradiction, from the theory and practice at home and abroad for many years proved that the use of 0.1HZ or lower frequency test power supply instead of industrial frequency AC withstand voltage test, not only can achieve the same test effect, and the power supply equipment is greatly reduced in size, weight is greatly reduced. The test procedure is greatly reduced, and has more superiority with the industrial frequency test.
Output frequency 0.1Hz, 0.05Hz, 0.02Hz
Carrying capacity 0.1Hz Hz max 1.1μF 0.05Hz Hz max 2.2μF 0.02Hz Hz max 5.5μF
Output voltage 30-90kv
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