Partial Discharge (PD) is a critical hidden danger affecting the safe operation of various power transformers, including the 10kv distribution transformer and 150 kva 3 phase transformer produced by JINSHANMEN TECHNOLOGY CO., LTD. As a professional manufacturer of power transmission and distribution equipment, JINSHANMEN TECHNOLOGY CO., LTD mainly produces oil immersed power transformers, dry-type power transformers, oil immersed three-dimensional coiled power transformers, dry-type three-dimensional coiled power transformers, mining explosion-proof dry-type transformers, mining explosion-proof mobile substations, amorphous alloy power transformers, on load capacity regulating power transformers, locomotive dry-type transformers, as well as prefabricated substations, modular substations, wind energy box type substations, high and low voltage switchgear and other transmission and distribution equipment. For electrical equipment such as 10kv distribution transformer and 150 kva 3 phase transformer, understanding partial discharge knowledge is essential to extend service life and ensure stable operation. This article will detail the basics of transformer partial discharge, including its definition, causes, hazards, detection methods and prevention measures.
1. What is Transformer Partial Discharge?
Partial Discharge (PD) refers to the phenomenon of local repeated breakdown and extinction that occurs at weak insulation points in the transformer insulation structure under a certain applied voltage, without immediately forming a complete insulation breakdown. This type of discharge limited to local positions (weak points) of the insulation is called partial discharge. The partial discharge capacity is relatively weak, difficult to perceive by human intuition, and can only be measured with professional testing equipment. For key equipment such as 10kv distribution transformer and 150 kva 3 phase transformer, even slight partial discharge will affect their service life and operation safety if not handled in time.
2. Causes of Transformer Partial Discharge
There are many causes of partial discharge in transformers, involving multiple aspects, mainly including the following categories, which are also applicable to 10kv distribution transformer and 150 kva 3 phase transformer:
2.1 From the perspective of insulation materials and structure itself
(1) Defects such as bubbles, impurities and cracks will affect the insulation performance of materials, leading to partial discharge. (2) The dielectric constant of bubbles is usually lower than that of insulators, so the electric field strength borne by bubbles is much higher than that of adjacent insulation materials, which is more likely to be broken down, thus causing discharge. (3) Unreasonable design of insulation structure. For example, the interlayer or turn field strength of dry-type transformer insulation structure is too high during design, which may also lead to partial discharge. (4) Insulators, metal bodies and other parts in transformers often have some sharp corners and burrs, which will lead to the concentration of electric field strength at specific positions, thus causing partial discharge.
2.2 From the perspective of operation process
(1) Long-term operation and load changes will lead to aging and wear of insulation materials inside the transformer, loss of original insulation performance, and easy occurrence of partial discharge. (2) Overvoltage. Overvoltage in power systems is one of the main causes of transformer partial discharge. Overvoltage may be caused by external factors (such as lightning strikes) or internal factors (such as switch operations). When the voltage exceeds the breakdown voltage of the material, partial discharge will occur.
2.3 From the perspective of installation and process
(1) Imperfect production process, such as poor vacuum control in the drying process, insufficient drying time and temperature, leading to residual gas in the coil. In the production process of 150 kva 3 phase transformer, this problem is particularly prominent if the process is not strictly controlled. (2) The transformer insulation may be damaged during installation, or the water content of insulation materials exceeds the standard due to long-term idleness, resulting in overall dampness of the transformer body, which may affect the partial discharge capacity. (3) Insufficient winding casting process level and poor assembly process (such as burrs in the production of high and low voltage leads or improper distance) may also affect the partial discharge capacity. The 10kv distribution transformer, which is widely used in power distribution systems, is also prone to partial discharge due to installation and process problems.
3. Hazards of Partial Discharge
Although the partial discharge of transformers has a small range, small energy and short time, it will also cause hazards in the long run, which are mainly reflected in the damage to insulation materials. This is particularly critical for 10kv distribution transformer and 150 kva 3 phase transformer, which are widely used in industrial and civil fields:
First, partial discharge directly bombards the insulation, causing local insulation damage, which may gradually develop into insulation breakdown. The electrolytic effect produced by discharge will generate active gases such as ozone and nitrogen monoxide, corrode local insulation and gradually cause insulation damage.
Second, the heat generated by partial discharge will also increase the local temperature of the medium, and even cause carbonization, further accelerating the aging of insulation materials and shortening the service life of transformers.
4. Detection Methods of Partial Discharge
To effectively detect partial discharge and avoid potential hazards, professional detection methods are required. The common detection methods of partial discharge include electrical measurement method, ultrasonic measurement method and chemical measurement method, which are widely used in the detection of 10kv distribution transformer and 150 kva 3 phase transformer:
Electrical measurement method: Use oscilloscopes, partial discharge instruments or radio interference instruments to find the discharge waveform or radio interference level, which is a common and accurate detection method compliant with IEC 60270 standard.
Ultrasonic measurement method: Detect the ultrasonic waves generated during discharge, convert the sound waves into electrical signals for analysis, and realize non-contact detection, which is suitable for on-site detection of transformers.
Chemical measurement method: Detect the content of various gases dissolved in oil and their increasing and decreasing change rules, usually called "chromatographic analysis", which is especially suitable for oil-immersed transformers produced by JINSHANMEN TECHNOLOGY CO., LTD.
5. Prevention Measures of Partial Discharge
To avoid the hazards of partial discharge and ensure the safe and stable operation of transformers such as 10kv distribution transformer and 150 kva 3 phase transformer, the following preventive measures can be taken, which are also the key quality control points of JINSHANMEN TECHNOLOGY CO., LTD in transformer production:
(1) Select insulation materials with good insulation performance to fundamentally reduce the occurrence of partial discharge.
(2) Regularly inspect and maintain the insulation materials of transformers, and timely replace aging and severely worn components to avoid insulation failure caused by material problems.
(3) Install overvoltage protection devices to timely detect and suppress overvoltage phenomena, so as to reduce the impact of overvoltage on transformer insulation.
(4) Install temperature monitoring devices to regularly detect the surface temperature change of transformers, and find out the hidden dangers of partial discharge in time through temperature changes.
Conclusion
Transformer partial discharge is an important factor affecting the safe operation and service life of power transformers. For 10kv distribution transformer and 150 kva 3 phase transformer, mastering the basic knowledge of partial discharge, doing a good job in detection and prevention, can effectively reduce the occurrence of faults. JINSHANMEN TECHNOLOGY CO., LTD, as a professional manufacturer of power transmission and distribution equipment, strictly controls every production process, adopts high-quality insulation materials, and effectively reduces the hidden danger of partial discharge in transformers, providing reliable and safe 10kv distribution transformer, 150 kva 3 phase transformer and other transmission and distribution equipment for global customers.