Application Cases

In today's smart grids and advanced power systems, high-frequency transient currents are prevalent. These transient currents are crucial indicators of disturbances and fault processes within the power system. Real-time monitoring of their waveform, frequency, and amplitude is essential for preventing issues and ensuring the safe and stable operation of the power grid. However, traditional current measurement methods face challenges such as narrow bandwidth, susceptibility to electromagnetic interference, and difficulties in insulation coordination, making it hard to effectively detect transient currents.

Aigtek's Contribution

This issue, Aigtek is excited to share a research paper published in the High Voltage Engineering journal by a customer from Xi'an Jiaotong University. The paper focuses on the development and performance testing of an optical current sensor. Let's take a look at the details.

Experiment Name: Application of the ATA-4014C High-Voltage Power Amplifier in the Performance Testing Experiment of Current Sensors

Research Direction: Development and Performance Study of Optical Current Sensors

Experimental Equipment: ATA-4014C High-Voltage Power Amplifier, Optical Current Sensing System, Signal Generator, Standard Current Probe, Oscilloscope, etc.

Experiment Content: This experiment involves the design of an interference-resistant solenoid-type wideband optical current sensor. Based on a sensor performance testing platform, the experiment investigates the steady-state response linearity to both AC and DC currents and the frequency response characteristics of the optical current sensor, completing the performance testing of the developed sensor.

Experiment Process:

The test circuit primarily consists of a combination of a signal generator and the ATA-4014C high-voltage power amplifier to form an adjustable input current source with arbitrary waveforms. A clamp-type standard current probe is used to measure the actual input current value, allowing for the testing and study of the sensor's various steady-state performance characteristics. The experimental platform is illustrated in the figure below.

Firstly, the linearity and sensitivity of the sensor are tested. Current is input into the solenoid through the signal source and power amplifier to generate a magnetic field, which induces the Faraday effect in the optical current probe. The resulting signal is then converted into a voltage signal by a detector and output to an oscilloscope for data processing. Subsequently, the frequency response characteristics of the sensor are tested to determine its measurement bandwidth. This is achieved by providing currents of different frequencies through the signal source and power amplifier, yielding output results from the optical current sensor under various input current frequencies.

Experiment Results:

(1) By adjusting the signal source to change the loop current, the output voltage of the optical current sensor under different input currents was obtained. The experimental data was then linearly fitted, with the results shown in the figure on the left below.

(2) The power amplifier was set to a constant current output mode with a fixed amplitude, maintaining a stable RMS current of 2A. The frequency of the input current was changed by altering the frequency of the signal generator. As the frequency increases, the inductive reactance of the non-inductive resistor also increases. When the current is kept constant, the load voltage rises, eventually reaching the output power limit of the power amplifier.

After testing, it was found that with a constant current of 2A, the frequency could be uniformly increased from 50 Hz to 1 MHz. This allowed for the determination of the sensor's amplitude-frequency response and phase-frequency response.

Specifications of the ATA-4014C High-Voltage Power Amplifier Used in the Experiment: