1、 The main content of the current transformer test project
The current transformer test project mainly includes basic parameter testing, primary current test, excitation characteristics, transformation ratio polarity, short-circuit impedance, rated load loss, rated secondary load, and other parameter measurements. The performance of the current transformer is judged to meet the requirements based on the test results. The primary circuit wiring resistance inspection mainly checks whether the resistance of the current transformer primary circuit is qualified to ensure the safe operation of the current transformer, The conversion characteristic test is conducted by measuring the relationship between the secondary current and input current of the current transformer, and analyzing the accuracy and stability of the current transformer.
2、 Specific process of current transformer test project
1. Preparatory work: Before conducting the test on the transformer, check the status of the testing equipment, take corresponding safety measures, confirm whether the required testing instruments are within the qualified period, and at the same time, inspect the test object to eliminate potential fault hazards.
2. Pre test preparation: According to the requirements of the test project, prepare the equipment and equipment required for the test, and operate one by one according to the predetermined test plan.
3. Basic parameter testing: During each test, it is necessary to fully understand the usage method and precautions of the instrument, and conduct tests on parameters such as short-circuit impedance, secondary DC resistance, excitation characteristics, rated load loss, etc. to ensure that the performance of the current transformer meets the requirements.
4. One pass current test: It is to verify the correctness of the circuit from the current transformer to the measurement and control device and protection device from the primary side, ensuring that the circuit of the current transformer is connected and avoiding affecting safe operation.
5. Transformation ratio test: Evaluate the accuracy and stability of the current transformer by measuring and analyzing the relationship between the secondary current and input current of the current transformer.
6. Excitation characteristic test: There are two principles for measuring excitation characteristics: power frequency method and low-frequency method. The power frequency method applies power frequency voltage to the CT secondary winding to test the voltage and current relationship of the CT secondary winding, that is, the volt ampere characteristic or excitation characteristic. This method has fast and intuitive characteristics.
7. Test data processing and analysis: Process and analyze the data generated during the test process, and evaluate the test results and performance of the current transformer.