The complete set offrequency conversion series resonance test equipmentis widely used in industries such as power, metallurgy, petroleum, and chemical. It can not only handle various specifications of power cables GIS、 Circuit breakers and enclosures can undergo AC withstand voltage tests, and the withstand voltage level of electrical equipment such as large generator sets, power transformers, and transformers can also be tested through certain frequency limitations.
In recent years, "urban and rural network transformation", high-voltage cross-linked cables, and GIS (composite electrical appliances) have been widely used, and the capacity and length of cables continue to rise. The previous DC withstand voltage test could not accurately reflect the actual insulation performance of the above-mentioned equipment. In the case of large capacity, ordinary power frequency test equipment is very bulky and not suitable for on-site use. The intelligence and miniaturization of thefrequency conversion series resonance test equipmentgreatly reduce the physical labor of the test personnel and improve work efficiency.
Principles of Transformer External Application Test and Precautions for Frequency Conversion Series Resonance Test:
External testing is a fundamental test for testing the main insulation of transformers. The test frequency shall not be less than 80% of the rated frequency.
Attention to the external test of transformer for the complete set offrequency conversion series resonance test equipment:
1. Tested winding, untested winding short circuit, untested winding short circuit after grounding. In principle, the tested product cannot be suspended in a potential way.
2. During the experiment, a dedicated grounding wire was used to connect the frequency conversion resonance system to the tested transformer casing.
Principle and precautions of induction withstand voltage test for complete set offrequency conversion series resonance test equipment
The transformer induction withstand voltage test is a basic test that simultaneously checks the main insulation and longitudinal insulation of the transformer. The test voltage is generally twice the rated voltage. In order to avoid iron core saturation, the testing frequency of the entire frequency conversion series resonance test device should be more than twice the rated frequency, generally between 100~400 Hz. Experience has shown that the testing frequency is more suitable within the range of 150-200 Hz.
The complete set offrequency conversion series resonance test equipmentis used to test the induction withstand voltage test of transformers. Precautions:
1. Apply power voltage from the low-voltage winding, and the neutral point of the high-voltage winding is not grounded. Non test phase winding is grounded for a short period of time.
2. If the transformer has medium voltage winding and balanced winding. Note that the potential of these windings should not pause.
3. The test compensation capacitor is located on the low voltage side. The voltage divider is located on the high voltage side.
4. During the testing process, the provided dedicated grounding wire should be used to connect the testing system and the tested transformer.
Complete set offrequency conversion series resonance test equipmentfor power frequency withstand voltage test and precautions:
The complete set of frequency conversion series resonance test equipment should be tested for AC withstand voltage in the manufacturing, installation, maintenance, operation, and preventive testing of generators in accordance with the regulations of national and local power departments. The waveform and frequency of the test voltage should be consistent with the ratio of the working voltage. The frequency conversion series resonance test is completed, and the test voltage is generally set to 0.75 (2UN3000) or 1.5UN, with a frequency of the power frequency; When testing the complete set of variable frequency series resonance test equipment, using appropriate compensation capacitors can meet the AC withstand voltage requirements of the generator