Power transformer, relays, transformers, capacitors, lightning arrester, etc high-voltage devices require periodic measurements of dielectric loss after long periods of operation. Therefore, high voltage tan delta tester is needed. Because this equipment is more complex, and is a high voltage power test equipment, so we need to master its working principle.

The set value after the high voltage begins to measure the frequency, and the frequency power of the output retarder of the PID algorithm is adjusted to the set value, then the measured frequency power of the circuit is measured to the high voltage, the low voltage is adjusted, and the high voltage output is accurate. The forward/backward wiring automatically selects and switches the current input range according to the test measurement circuit, measures the Fourier transform circuit to filter out the interference provided, the fundamental signal is separated, and the standard current vector computes the current sample, calculating the capacitance Angle difference of the amplitude calculated as tgδ. The measurement is repeated many times, and the intermediate result of the sorting is selected. At the end of the measurement, the measurement circuit sends down the delay frequency power to 0V.

The high voltage tan delta tester has two measuring methods according to whether the object under test is grounded or not. The principle of the two measurement methods is shown in the figure.

At the 10kV side of the high voltage power supply, the high voltage is divided into two channels, and the dielectric loss of capacitor CN is very small, which can be considered as zero, that is, the capacitive current. It can be used as a reference for capacitive current. On one side of the Cx sample, the current of the sample can be decomposed into horizontal component and vertical component. By calculating the ratio of horizontal component to vertical component, the value of tg can be obtained.