Surface Resistance Rate

Summary

The Integrated Precision Oil Dielectric Loss and Volume Resistivity Tester is a high-precision instrument designed for the measurement of dielectric loss angle and volume resistivity of insulating oils and other liquid insulating media. Internally, it integrates key components such as the dielectric loss oil cup, temperature controller, temperature sensor, dielectric loss test bridge, AC test power supply, standard capacitor, high-resistance meter, and DC high-voltage source. The heating section employs the advanced high-frequency induction heating method, which offers benefits such as non-contact between the oil cup and the heating element, even heating, rapid speed, and easy control. The AC test power supplyAC-DC-ACThe conversion method effectively avoids the impact of fluctuations in grid voltage and frequency on the accuracy of insulation loss testing, even when generators are producing power. The internal standard capacitor isSF6Inflatable ThreeExtreme.The model capacitor maintains consistent dielectric loss and capacitance regardless of environmental factors such as temperature and humidity, ensuring the instrument retains precision even after prolonged use.

The instrument is internally equipped with full digital technology, featuring fully automated measurement, multiple modes, and is equipped with a large screen.320×240Touchscreen display, full Chinese menu, with Chinese prompts for each step, test results can be printed out, and operators can master the operation without professional training.

Operation Principle

uHeat

Equipment utilizes a high-frequency induction furnace for heating, following the activation of heating, temperature controlCPUInitiate the heating command while simultaneously collecting the temperature values from the internal oil cup temperature sensor. Heating is implemented with variable power control.PWMCombining both control methods. When the oil sample temperature is low, use high-power heating, which is beneficial for shortening the heating time of the oil sample; as the temperature rises to near the preset temperature, switch to lower power.PWMHeating methods ensure even oil sample heating.

The high-frequency induction furnace heating avoids the uneven heating phenomenon of the heating block.

We have implemented precise temperature control.

As the actual temperature approaches the preset temperature, the temperature controlCPUAdopting low-powerPWMMethod of heating, sampled temperature valuePIDOperations and analysis yield excellence.PWMMaintain a precise duty cycle to ensure the temperature is strictly controlled within the preset temperature error range.

U-value Measurement

Test voltage is simultaneously applied to the instrument's internal standard capacitor and the oil cup under pressure.Extreme.Above, the circuit measurements are conducted for these two signals.PGAAfter control, synchronize the signals of the two channels.ADSampling, transmitting digital signalsDSP(Digital Signal Processor)DSPFilter the content.FFTPost-computation calculationtgδ、C x  Parameters such as ε, etc., delivered to the main controllerCPU。

Volume resistivity measurement

Direct current high-voltage test voltage applied to the oil cup pressureExtreme.Upon testing the circuit, a faint current signal was generated, which was then amplified by the measuring circuit and sent in.ADSampling, transmitting digital signalsDSP(Digital Signal Processor)DSPProcess the signal and calculateRxParameters such as ρ, etc., are sent to the main controller.CPU。