Causes of fire and explosion in transformers - News - Global IC Trade Starts Here.

Transformer is a device that operates based on the principle of electromagnetic induction, converting alternating current energy into another form of electrical energy with different parameters such as voltage and current. Inside the transformer, insulating components like gaskets and brackets are typically made from organic combustible materials such as paper, cotton, cloth, or wood, and they are often impregnated with a significant amount of insulating oil. For example, a 1000 kW transformer may contain approximately 0.012 cubic meters of wood, 40 kg of paper, and one ton of insulating oil. Due to these flammable materials, transformers pose a serious fire risk. If there is a severe overload or short circuit inside the transformer, the insulating materials and oil can be exposed to high temperatures or arcing, leading to decomposition and combustion. This process generates a large volume of gas, causing a rapid increase in internal pressure. The tank may rupture, releasing a large amount of oil, which can spread the fire and result in widespread power outages, disrupting normal production and daily life. There are several common causes of transformer fires and explosions during operation: 1. **Insulation Damage** - **Coil Insulation Degradation**: Prolonged overloading can cause the coils to heat up, leading to gradual insulation aging. This may result in inter-turn short circuits, phase-to-phase short circuits, or ground faults, potentially causing the transformer to explode. Before installation and operation, it's essential to test the insulation strength and avoid overloading during use. - **Poor Oil Quality or Low Oil Level**: Contamination from moisture, impurities, or other oils can significantly reduce the dielectric strength of the insulating oil. When this strength drops below a critical level, a short circuit may occur. It’s important to test the oil before putting it into service and regularly during operation. - **Core Insulation Aging**: Aging between silicon steel sheets or damaged bolt sleeves can lead to excessive eddy currents, increasing temperature and accelerating insulation degradation. Regular testing of core insulation is necessary, and any issues should be addressed promptly by replacing damaged parts. - **Inadvertent Maintenance**: During inspections, accidental damage to coil insulation or porcelain bushings can lead to flashovers and subsequent short circuits. Care must be taken during maintenance to prevent such damage, and after repairs, all components should be checked thoroughly for safety. 2. **Poor Electrical Connections** Poor contact at joints between coils, between coils and porcelain bushings, or at tap changers can cause localized overheating, damaging insulation and leading to short circuits or open circuits. High-temperature arcs generated during such events can rapidly decompose insulating oil, creating gas and increasing internal pressure, which may result in catastrophic failure. To prevent this: - Tighten loose bolts and inspect connections when the transformer is out of service. - Ensure proper cleaning and quality checks on welded joints. - Check and tighten tap changer contacts carefully before operation. 3. **Short Circuit on Load** A short circuit on the load side can cause a large current to flow through the transformer. If protective systems fail or are improperly set, the transformer can be damaged. It is crucial to install proper short-circuit protection, including fuses on both high and low voltage sides, and additional protections such as overcurrent relays, gas relays, differential protection, and temperature monitoring. 4. **Improper Grounding of Secondary Side** The secondary side (380/220 V) of an oil-immersed transformer must be properly grounded. If the three-phase load is unbalanced, current may flow through the neutral line. If the grounding point has high resistance, it could become hot enough to ignite nearby materials. Regular checks of the grounding connection and testing of grounding resistance are essential. 5. **Lightning Protection** Transformers connected via overhead lines are vulnerable to lightning strikes, which can generate overvoltage and penetrate the insulation, potentially causing fire. Installing proper lightning protection systems is essential to prevent such incidents. In addition to these factors, operators should monitor the sound of the transformer, track temperature changes, check oil levels and color, and take immediate action if any abnormalities are detected. These precautions help ensure the safe and reliable operation of the transformer.

Piezoelectric Elements For Inkjet Piezo Transducer

Piezoelectric ceramic ring



Applications: ultrasonic vibration tranducer for inkjet printer



Vibration mechanism of inkjet printer:

Generally, it is composed of piezoelectric ceramics and driving rods. By high-frequency electric excitation, piezo ceramics produce high-frequency ultrasonic vibration (above 60 kHz or higher), which is transmitted to the driving rod and generates high-frequency micro-displacement (back and forth expansion) at its front end.

Piezo ceramics components features :

1. High vibration amplitude and can withstand higher power.
2. The product has high reliability, strong maintainability, and is not easy to break down or off-line.
3. The frequency can be adjusted in a wide range, generally within the range of 10KHz.





Yuhai support all the new developping transducer, Welcome the customized elements inquiry.




The present piezoelectric elements for Inkjet piezo transducer is following :



Piezo rings OD4*ID2*2.5mm price USD1.20/pc, 2000pcs
Material: PBaS-4
Fr.: 694 KHz ±5KHz
K33: ≥0.55
Tg loss <0.5%
Ct 60pF ±12.5%

Piezo rings OD4*ID2*2.5mm price USD1.20/pc, 2000pcs
Material: PSnN-5
Fr.: 626KHz ±5KHz
K33: ≥0.57
Tg loss < 2%
Ct 53pF ±12.5%

Piezo rings OD6*ID2.5*2mm price USD1.50/pc, 2000pcs
Material: PZT-41
Fr.: 785 KHz ±5KHz
K33: >0.53
Tg loss < 0.5%
Ct 107 pF ±12.5%

Piezo rod OD3*7mm price USD1.20/pc, 2000pcs
Material: PLiS-51
Fr.: 192 KHz ± 3KHz
K33: >0.62
Tg loss < 2%
Ct 18.7 pF ±12.5%

Inkjet Piezo Transducer,Piezoelectric Vibration Transducer,Piezoelectric Rings,Piezoelectric Elements For Inkjet Piezo Transducer

Zibo Yuhai Electronic Ceramic Co., Ltd. , https://www.yhpiezo.com