Partial Discharge (PD) is a common phenomenon in high-voltage electrical equipment, which may lead to performance degradation or even failures. To prevent these issues, the power industry widely adopts ultrasonic partial discharge inspection instruments to monitor and assess the insulation status of equipment. This article will introduce the basic principles, features, applications, and operating methods of ultrasonic partial discharge inspection instruments.
Basic Principles
The ultrasonic partial discharge inspection instrument detects by capturing the ultrasonic signals generated during partial discharge in high-voltage electrical equipment. When partial discharge occurs, in addition to electromagnetic waves, ultrasonic signals with frequencies higher than 20 kHz are also produced. These signals can be captured by ultrasonic sensors and analyzed through signal processing techniques to determine the presence, type, and severity of partial discharge.
Technical Features
The ultrasonic partial discharge inspection instrument has the following notable features:
Non-invasive detection: It can complete detection without power outage, without affecting normal operation.
Strong anti-interference capability: Ultrasonic signals are less susceptible to electromagnetic interference, suitable for detection in complex environments.
High sensitivity: It can detect very weak ultrasonic signals, with a minimum detectable discharge amount of a few picocoulombs (pC).
Intuitive display: It is usually equipped with a color LCD screen, displaying information such as ultrasonic signal waveforms and frequency spectra.
Multi-functional integration: It supports multiple detection modes, such as continuous mode and flight mode, adapting to different types of power equipment.
Easy operation: It is typically equipped with a simple user interface for convenient on-site operation.
Construction
A typical ultrasonic partial discharge inspection instrument includes:
Ultrasonic sensor: Used to capture ultrasonic signals.
Signal acquisition unit: Includes preamplifiers, filters, etc.
Signal processing and display module: Includes digital signal processors (DSP), LCD screens, etc.
Power module: Built-in battery or external power adapter.
Application Scenarios
Ultrasonic partial discharge inspection instruments are widely used in the following scenarios:
Power equipment maintenance: For regular inspection of equipment such as power transformers, GIS (Gas Insulated Switchgear), cable terminations, etc.
Quality control: For quality inspection during the manufacturing process of power equipment.
Scientific research: For studying the performance of new insulating materials in laboratory environments.
Operating Methods
Here are the general steps for using an ultrasonic partial discharge inspection instrument:
Preparation:
Check the battery level of the tester to ensure it is sufficient.
Prepare the corresponding sensors and ensure they are in good working condition.
Connect the sensor:
Install the ultrasonic sensor on the equipment under test, ensuring good contact.
Set test parameters:
Adjust the display mode, sampling rate, and other parameters of the tester as needed.
Set an appropriate trigger level to capture ultrasonic signals.
Start testing:
Begin recording data, and observe the waveform changes on the display screen.
Data analysis:
Analyze the waveforms and record any abnormal phenomena.
Use built-in software or export data to a computer for further analysis.
Report preparation:
Prepare a detection report based on the analysis results and propose necessary recommendations or corrective measures.
Precautions
Before conducting tests, ensure all safety operating procedures are followed.
For complex test scenarios, professional guidance may be required.
After testing, disconnect the sensor from the equipment and turn off the tester.
Conclusion
Ultrasonic partial discharge inspection instruments play an important role in the maintenance and management of the power industry due to their efficiency and accuracy. By conducting regular inspections of power equipment, failures can be effectively prevented, ensuring the stable operation of the power system.
