Technology Literature

The Harm of Partial Discharge of Transformer

When the transformer generates partial discharge under the working voltage, even a very weak discharge will cause corrosion to the insulating material. In the long run, the accumulation effect will affect the dielectric property of the insulation, causing the insulation to deteriorate until the insulating layer is finally broken. The chemical elements generated during the discharge process will accumulate on the solid insulation, which further excites the discharge of electrical equipment, and it is easier to break through the insulation in areas with high field strength and insulation damage. And eventually form a carbonized layer through the insulation

One of the causes of transformer failure is dielectric breakdown, which is mainly caused by partial discharge, which causes insulation deterioration and even breakdown. With the development of transformer fault diagnosis technology, people gradually realize that partial discharge is the root cause of many faults and accidents of transformers, so the test of partial discharge is getting more and more attention. In recent years, 50% of power transformer accidents above 110kV are caused by inter-turn short circuit under normal operating voltage, and also caused by partial discharge. Therefore, partial discharge measurement has been taken as one of the important projects for 220kV transformer handover and overhaul. Condition monitoring and troubleshooting will be very effective.


Through the discussion of transformer-related tests, we can see that in the handover test, the relevant test of the transformer is the inspection of the overall insulation of our transformer.


Only by conducting an effective insulation test on the transformer can we judge whether the insulation of the transformer meets our operational requirements. This is the main means by which we can judge whether the transformer can be put into operation.

Read More About : partial discharge tester transformer neutral grounding resistor



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


Related Articles:

What Test Items are Required for 110kV/220kV Substation Acceptance and Maintenance Testing?

What Tests Must be Done before the Transformer Leaves the Factory?

Main Factors Affecting the Operating Life of Transformers

What is the Purpose of Measuring the DC Resistance of the Transformer Winding?

Points to note in transformer oil breakdown voltage (BDV) test

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