Industry News

Importance of transformer insulation resistance

It is pointed out that the damage of the distribution transformer is mostly caused by electrical breakdown and electrochemical breakdown, and the defects of the dielectric medium are the main causes of electrical breakdown and electrochemical breakdown. In order to avoid the damage of the insulating medium, the transformer overload should be limited and the short circuit should be prevented. In the work, the transformer field test should be done to strengthen the insulation supervision of the transformer oil; to prevent overvoltage and overcurrent, it should be installed properly. Overcurrent, overvoltage protection, periodic measurement of transformer insulation and oil temperature. In terms of operation management, it is necessary to strengthen inspection and inspection, and focus on the operation sound, oil level and temperature of the transformer, so as to detect the partial discharge defects between the layers and deal with them in time to avoid transformer damage.


According to statistics, various faults of high-voltage power grids are mostly caused by damage of high-voltage electrical equipment insulation. Therefore, understanding the insulation characteristics of equipment, mastering the insulation status, and continuously improving the insulation level of electrical equipment are the fundamental guarantee for the safe and economic operation of power systems.


As the main equipment of the power system, it is very important and necessary to maintain good insulation during operation. In order to ensure the insulation level of the transformer, a series of insulation tests are to be carried out from the manufacture of the transformer. These tests include: insulation testing of raw materials at the time of manufacture, intermediate testing of the manufacturing process, qualitative and factory testing of the product, handover test after installation on site, and insulation preventive test for maintenance operation during use. Among them, the handover test and preventive test of the transformer are the two most important tests, and the handover test not only has a judgment on the overall insulation of the transformer. It also provides basic information for preventive testing during future operations. Therefore, the infrastructure personnel must pay special attention to the accuracy and authenticity of the handover test in the infrastructure construction process. At the same time, it is necessary to understand the insulation test content and principle of the transformer in the handover test.


Kingrun series transformer JIM insulation resistance tester provides a reliable guarantee for the testing of transformer insulation resistance


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DC winding resistance tester with 500 times tests on a single charge -JYR9310

The test items are required for 110kV/220kV substation acceptance and maintenance testing(with corresponding tester types):

Test Object

Testing Item

Tester Type

Cable

Cable AC Hipot Testing

JYCX

Details

Cable Insulation Resistance Testing

JYM KYORITSU

Details

Transformer

Insulation Resistance of Winding

    JYM KYORITSU

Details

DC Leakage Testing in 1min

JYDHV

Details

Winding Resistance Testing

JYR50S

Details

Winding Deformation Testing

JYP

Details

Turns Ratio Testing

JYT-A

Details

AC Hipot Testing

JYCX

Details

Short Circuit Impedance Testing

JYW6300

Details

Dan Delta Testing

JYC

Details

Oil Breakdown Voltage (BDV)Testing

JY6611

Details

Oil Tan Delta Testing

GTD-61A

Details

Switchgear

Circuit Breaker/Disconnector Resistance

JYL-200B

Details

Relay

Relay Performance

JY7003G

Details

On-load

On-load Switchgear Testing

JYK-I

Details

Tap Changer Dynamic Testing

JYK-I

Details

Instrument   Transformer

Current Transformer (CT)Testing

JYH-C

Details

Potential Transformer (PT)Testing

JYH-C

Details

Surge Arrestor

Zinc Oxide Characteristics Testing

JY6800

Details

1mA DC Reference Voltage

JYDHV

Details

Capacitor

Capacitor Current

JY6700

Details

Capacitor Inductance

JY6700

Details

Ground Grid

Grounding Down Lead Earth

JYD

Details