1. Introduction
Partial discharge is a sign and manifestation of insulation degradation in power equipment, and is also the cause of further insulation degradation. Since the consequences of insulation breakdown are often serious, it is particularly important to detect partial discharge in power equipment. Partial discharge in electrical equipment is an electrical discharge that does not completely short-circuit the electrodes. The amplitude of such discharges is usually small, but they can cause the insulation to continue to deteriorate, which may lead to eventual failure. Live partial discharge detection provides a quick and simple method to identify potential insulation faults that may cause power outages or personal injury.
In accordance with the relevant live detection requirements of the State Grid's "Technical Specifications for Live Detection of Power Equipment", this instrument integrates ultrasonic detection, transient ground voltage (TEV), ultra-high frequency (optional), high frequency (optional) partial discharge detection, and comprehensively uses computer technology, ultrasonic, transient ground wave, ultra-high frequency, high frequency sampling technology, analog electronic technology, high-speed signal acquisition technology and advanced digital signal processing technology. It is developed based on the Linux operating system platform and provides partial discharge spectra, amplitude phase spectrum waveforms and discharge signal quantization values. Through static or dynamic detailed observation and analysis of single-cycle or multiple-cycle partial discharge pulse waveforms, the partial discharge of electrical equipment can be better evaluated. It is suitable for daily inspection of the insulation performance of switchgear, high-voltage cables, power transformers and other electrical equipment. It has the characteristics of high sensitivity and strong adaptability, and can effectively detect its related insulation defects. It is an ideal tool for status detection of power equipment during live operation.
II. Functional characteristics
1 It can quickly detect the partial discharge status of high-voltage electrical equipment, especially switchgear, on-site. It is easy to use, small in size, light in weight and easy to carry.
2 The design circuit of the partial discharge detection sensor uses advanced RF signal processing, high-frequency signal processing and weak signal processing technology, and adopts high-precision AD conversion and high-speed digital signal processing chips for digital signal processing, which has good anti-interference performance and measurement accuracy.
3 It combines ultrasonic, transient ground wave, contact ultrasonic and ultra-high frequency to detect partial discharge signals.
4 Built-in non-contact air sound sensor TEV sensor.
5 It has multiple windows such as waveform diagram, phase diagram, bar chart, four-element diagram, etc. to analyze partial discharge test data.
6 It supports data storage and viewing functions, and can directly export data through SD card or USB.
7 It supports multi-level threshold settings for attention and alarm, and provides intuitive prompts for problems through different amplitude colors.
8 It is powered by a large-capacity lithium battery and can work continuously for more than 10 hours on a single charge.
III. Hardware composition
(1) TEV sensor: Built-in TEV sensor, which is placed close to the part to be tested during testing.
(2) AA sensor: built-in non-contact ultrasonic sensor, pointing to the part to be tested during testing.
(3) 3.5-inch touch screen: measurement data and waveform display, interactive via touch screen.
(4) Cancel/return key: cancel or return operation during interface interaction.
(5) Power on/confirm key: press this key to turn on the device when it is off, and it serves as a confirmation key after entering the interface.
(6) Four direction keys: used to switch options, modify setting values, etc.
(7) Headphone jack: headphone jack for ultrasonic partial discharge listening.
(8) TYPE-C interface: can be used as a charging interface or a data transmission interface. The indicator light is red when charging and green when fully charged.
(9) SD card interface: screenshot or video data storage.
(10) External AA/AE/HF: connected to a non-contact flexible probe or an external contact ultrasonic sensor or a high-frequency sensor via a signal line.
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