With the continuous improvement of the reliability requirements for the operation of power grid equipment, partial discharge detection has become a common practice in transformers GIS、 An important part of preventive testing for key equipment such as cables. How to choose a transformer partial discharge tester that is suitable for the actual needs of our unit is a practical problem faced by many power workers when purchasing. Wuhan UHV Power Technology Co., Ltd., based on years of experience in the high-voltage electrical measurement industry, provides the following selection references for industry users - the aspects of voltage level matching, accuracy requirements, usage scenarios, acceptance standards, and later maintenance.

1、 Voltage level matching is the primary consideration

Before purchasing a partial discharge detector, the technical department should first clarify the actual usage needs of the unit. The range of the partial discharge detector is selected based on the highest voltage level of the equipment under the jurisdiction of our unit. The specifications required for the 10kV distribution network and 110kV substation are completely different. Taking the Wuhan UHV product system as an example, the economical type is suitable for daily 10kV distribution equipment testing, with functions meeting basic needs and relatively low prices; The standard type covers voltage levels 35kV to 110kV, with data storage and communication functions, and is the most commonly purchased specification by power supply companies.

2、 Selection of accuracy level comparison standards

The accuracy level requirements need to be determined in accordance with relevant GB/T or DL/T standards. The higher the accuracy, the higher the price, and it is sufficient. At present, the mainstream digital partial discharge detectors meet the standards of IEC60270 and GB/T7354-2018, and can measure and record partial discharge as well as AC test voltage. Taking the UHV-2000B partial discharge tester as an example, its detection sensitivity can reach<1pC, and the measurement range covers 0.01pC to 10000nC; the sensitivity of the UHV-2000A partial discharge complete set device is 0.1pC, and the measurement range is 0.1pC to 100000pC.

3、 The selection of equipment is determined by the usage scenario

If the frequency of outdoor use is high, it is recommended to choose a model with a dust-proof and waterproof shell, which is not necessary for indoor fixed use. For scenarios that require continuous online monitoring, equipment that supports both partial discharge measurement and online monitoring functions can be selected. In addition, the partial discharge detection of almost all high-voltage electrical equipment can be realized by configuring different sensors, providing time domain waveform, PRPD, PRPS and other discharge patterns, and realizing the analysis of different discharge types.

4、 The acceptance of goods upon arrival cannot be ignored

After the equipment arrives, it should be jointly inspected by the technical specialist and the user team. Only after passing the inspection can it be stored or put into use. The acceptance content includes: visual inspection, checking for any scratches or deformations on the casing, checking for cracks on the display screen, and checking for normal functionality of all interfaces and buttons; Random data verification, checking whether the factory inspection report, certificate of conformity, operation manual, and calibration certificate are complete; Power on test, perform no-load power on test according to the operation manual to confirm that all displays and functions are normal.

5、 Include later maintenance in the procurement budget

The procurement cost is only a part of the total cost of ownership, and the expenses for later calibration, maintenance, replacement, and consumables also need to be included in the budget. According to the JJG metrological verification regulations, partial discharge detectors should be sent for inspection once a year. In actual work, some units adjust the frequency of use to calibrate once every six months. The annual calibration fee for each unit sent to the metrology institute ranges several hundred to a thousand yuan. The measuring cables and probes are vulnerable parts and need to be replaced on average once every 1 to 2 years.

Wuhan UHV Power Technology Co., Ltd. is located in Wuhan, China Optics Valley. It is an enterprise dedicated to the field of high-voltage power testing, integrating scientific research, development, production, sales, and service. The partial discharge testing system adopts advanced ultra-high frequency sensors and digital filtering technology, with a detection sensitivity of up to 0.1pC, which can accurately identify subtle defects in the early insulation of power equipment. At present, the company's main products include series resonance testing devices, partial discharge testing systems, high-voltage insulation withstand voltage, transformer testing, circuit breaker testing, relay protection and other series.