Current transformer ratio test method - Database & Sql Blog Articles

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

inductance

The current transformer is a special transformer specially used for transforming current. Under normal working conditions, the secondary current is substantially proportional to the primary current, and when the connection direction is correct, the phase difference of the secondary current to the primary current is close. At zero.

As a key equipment in the power system, the current transformer is very important for its electrical performance test. For the current transformer, the ratio test is an indispensable test item. The current transformer ratio is related to the accuracy of the measurement. Reliability and protection.

The current transformer field ratio test generally adopts the current method. The current method is used to measure the current transformer ratio. In fact, it is the actual operating condition under the condition of rated current. It is an ideal test method, and the measurement accuracy is high. However, with the continuous development of the power system, the capacity of a single generator is getting larger and larger, and its outlet current has reached tens of thousands of amps.

For example, a 800 MW generator set with a rated voltage of 20 kV and a rated current of 800/(20×31/2) = 23.094 kA, the corresponding current transformer has a large current, if the current is used to measure the primary current Wan'an's current transformer ratio is difficult to achieve at the scene:

First, the rated large current is difficult to reach (requires a large-capacity regulator);

Second, the required standard current transformer or current booster is bulky and expensive. If the primary current of the current transformer under test is reduced, the error will be large and the test will be meaningless.

Therefore, the method of measuring the current transformer ratio by the current method is increasingly restricted at the construction site. On the basis of the current method, the author introduces another test method for the current transformer ratio-voltage method. The method is suitable for testing the current transformer ratio at the construction site. The voltage method has the advantages of wide application range, less equipment and simple equipment, and is a simple and convenient test method.