Xuchang Chengrui Insulation Materials Co., Ltd.
Henan Province, China
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Ever wondered what keeps transformers humming safely for decades? Insulating paper plays the stealthy hero. Made from tough cellulose or layered composites, it wraps coils and shields cores, blocking electrical leaks that
could spark disasters. Think of it as armor—fighting off heat, moisture, and voltage surges to keep energy flow clean.
Top-grade versions ace extreme tests: baked at 200°C, dunked in humidity, or zapped with lightning-like charges without flinching. No fluff here—industrial transformers demand papers certified by IEC/ISO norms for precision performance. Sourcing from niche manufacturers? Smart move. Their engineered sheets fit unique voltage gaps, prevent aging cracks, and ensure your transformer runs smoother, longer.
The following are the main types of insulating paper commonly used in transformers:
Kraft paper: Kraft paper is widely used in transformers because of its good mechanical strength and electrical properties. It has high voltage resistance and good thermal stability, can effectively isolate the circuit, and has a relatively low cost. Kraft paper also has good flexibility and folding resistance, which is convenient for installation and fixing inside the transformer.
NOMEX paper (or Nomi paper): NOMEX paper is a high-performance insulating material with excellent electrical properties, thermal stability and mechanical strength, and can withstand high temperatures and voltages. Compared with kraft paper, NOMEX paper is more resistant to high temperatures and is suitable for transformers in high temperature environments. In addition, its aging resistance is also very good, which can ensure the long-term stable operation of the transformer.
NMN insulating paper: The thickness of NMN insulating paper is between 0.1 and 0.5 mm. Although there is less specific information, it is also one of the commonly used insulating materials in transformers.
Sanmu insulating paper: Also known as kraft paper, it is yellow in color and has a thickness between 0.13 mm and 0.5 mm. Sanmu insulation paper has good mechanical strength and electrical properties, suitable for transformer insulation needs.
Aramid paper: Aramid paper is a synthetic fiber paper with high strength, high modulus and good electrical properties. It is usually used in applications that require high strength and high heat resistance.
The characteristics of transformer insulation paper mainly include the following points:
High temperature and anti-aging: Transformer insulation paper can withstand high temperature, is not easy to age, has high stability, and can withstand the test of long-term high temperature and strong electric field environment.
Excellent insulation performance under low humidity: In a low humidity environment, transformer insulation paper has good insulation performance, which can effectively protect the internal structure of the transformer and prevent leakage and arc faults.
Strong electrical breakdown resistance: Transformer insulation paper can withstand the test of high voltage, has strong electrical breakdown resistance, and can effectively prevent arc and faults inside the transformer.
Good mechanical strength: Transformer insulation paper has high mechanical strength, which can effectively prevent the transformer from being damaged by external impact and extrusion.
Chemical compatibility: Transformer insulation paper can resist the erosion of most solvents, and is highly resistant to corrosive substances such as acids and alkalis. It is also easily compatible with various varnishes, adhesives, transformer fluids, lubricants, and refrigerants.
Radiation resistance: Transformer insulation paper can maintain its mechanical and electrical properties even when the ionizing radiation intensity reaches 800 megarads.
Non-toxic/flame-resistant: Transformer insulation paper does not produce any known toxic reactions to humans or animals, and does not melt or support combustion in the air, meeting the flame-resistant requirements.
Humidity stability: In an environment with a relative humidity of up to 95%. the dielectric strength of transformer insulation paper can still maintain 90%. of that in the dry state, and most mechanical properties are improved under this condition.
Insulating paper is the backbone of transformer durability, engineered to resist electrical arcing, heat degradation, and physical wear. Critical specs vary by application:
● Dielectric Strength: Ranges from 40 kV/mm (low-voltage units) to 100 kV/mm (high-voltage cores).
● Thermal Endurance: Class A (105°C) for basic models; Class H (180°C) for heavy-duty or overload scenarios.
● Tensile Strength: 50–120 N/cm² to prevent tearing during winding or thermal expansion.
Thinner grades (0.05–0.2mm) suit layered windings, while thicker sheets (0.3–0.5mm) act as barriers in oil-filled units. Materials like aramid blends outperform standard cellulose in moisture resistance (<3%. absorption) and partial discharge tolerance. Compliance with IEC 60641-2 and ASTM D202 non-negotiable for grid reliability.
Parameter | Typical Range | Key Standard |
Dielectric Strength | 40–100 kV/mm | IEC 60641-2 |
Thermal Class | A (105°C) to H (180°C) | IEEE 98 |
Thickness | 0.05–0.5 mm | ASTM D202 |
Tensile Strength | 50–120 N/cm² | ISO 1924-2 |
Moisture Absorption | <5%. (cellulose), <3%. (aramid) | IEC 60893-3 |
aw materials dominate—cellulose is cheaper (10–15/kg)butaramid/nomexhikespricesto10–15/kg)butaramid/nomexhikespricesto35+/kg. Thickness matters: 0.1mm sheets cost 20%. less than 0.4mm equivalents. Certifications like UL or IEC add 15–25%. vs. generic options. Need fire resistance or oil-proofing? Tack on another 12–18%.
Bulk buys (500kg+) trim unit costs by 10%, but low-volume orders face 30%. markups. Regional suppliers in Asia undercut EU/US brands by 20%. though quality audits are a must. Specialty demands—custom widths, pre-impregnated resins, or UV stability—balloon quotes fast.
Pro Tip: Skip over-spec’ing thermal class (e.g., Class H for a 105°C application). Balance dielectric needs (60 vs. 100 kV/mm) to avoid $$$ overkill. Test reports? Negotiate bundled pricing.
Key factors: Material > Certs > Thickness > Volume > Niche specs.
Insulation paper wraps coils to halt 10kV+ sparks from frying windings. Without it, heat (up to 150°C!) melts wire coatings in hours. Bonus perks: acts as a spacer for oil flow, stops copper dust from causing partial discharges, and resists transformer oil’s acidic gunk.
Thinner sheets (0.08mm) handle layered winding stress; thicker grades shield HV bushings. Materials like cellulose or aramid balance cost vs. thermal beast mode. Fun fact: Bad paper = 70%. of transformer failures. Skip it, and you’ve got a $50k paperweight.
Transformers rely on layered defenses. Cellulose paper (cheap, 90°C rating) wraps windings but yellows with heat. Upgrade to aramid (Nomex) for 220°C tolerance—$$$ but lasts decades. Mineral oil drowns arcs and cools coils but leaks = fire risk. Epoxy resin seals bushings; crack it and you’ve got a DIY fix gone wrong.
Mica tape handles 100kV+ surges but tears if bent wrong. Laminated wood (cheap) braces cores but warps in humidity. For HV monsters, crepe paper + oil combos block 150kV/mm breakdowns. Skip ceramic—too brittle for vibrations.
No “one-size” answer. Cellulose paper (12/kg) rules budget jobs but yellows at 90°C. Need heat beast mode? ‌**Nomex (aramid)**‌ laughs at 220°C but costs 40+/kg—ouch. Epoxy resin seals cracks but shatters if flexed. Silicone rubber bends like Gumby but swells in oil.
For HV monsters: crepe paper + oil blocks 200kV surges. Cash-strapped? Laminated wood braces cores cheaply but rots in dampness. Mica tape ($$$) handles 500°C arcs but tears if mishandled.
Pro tip: Mix materials. Wrap coils in cellulose, armor hotspots with Nomex. Testing trumps theory—demand UL/IEC reports.
Reality check: “Best” = balancing heat class, voltage stress, and wallet pain. Skip the hype—overkill insulation burns cash faster than faults.
Transformer insulation paper is a composite material composed of cardboard and insulation paper, and its working principle is based on the insulation properties of the material. Insulation paper can withstand a certain voltage and current, preventing the current from passing directly through the metal parts inside the transformer, thereby protecting the transformer casing from the risk of electric shock and short circuit. Specifically, the role of insulation paper in the transformer is as follows:
Isolation function: Insulation paper isolates the transformer bracket from the newborn environment to prevent the newborn transformer from affecting normal operation.
Protection function: Protect the insulation system of the transformer to prevent failures and accidents caused by insulation failure.
Withstand pressure and temperature: Insulation paper can withstand a certain pressure and temperature to ensure that the transformer can still operate normally under overload and overtemperature conditions.
Selecting optimal transformer insulation paper demands careful evaluation of multiple technical specifications:
Dielectric Properties Assessment
Material selection primarily hinges on insulation effectiveness variations across paper types. Traditional kraft paper (Sanmu insulation grade) offers yellow-colored sheets ranging 0.13-0.5mm thickness, while advanced NOMEX® variants (polyamide-based) present light yellow options from 0.05mm to 0.76mm. For mid-range applications, NMN insulation paper typically measures between 0.1-0.5mm thick.Thermal Endurance Considerations
Temperature resilience critically impacts material longevity. Laboratory tests show NOMEX® specimens retain approximately 80%. of initial mechanical strength at sustained 200°C operation. Remarkably, even after 100-hour exposure to 260°C extremes - beyond standard operational requirements - this material preserves 65-70%. structural integrity.
Durability & Environmental Resistance
Mechanical robustness combined with moisture resistance proves essential for operational safety. Hygroscopic degradation accelerates cellulose breakdown in insulation media, particularly concerning as absorbed moisture can decrease dielectric strength by up to 50%. in humid environments. Premium-grade papers demonstrate enhanced resistance to chemical decomposition and mechanical stress factors.
Practical Implementation Factors
Field technicians should balance performance needs with budget constraints when specifying materials. While specialty papers like NOMEX® command premium pricing (typically 3-5× conventional options), their extended service intervals often justify initial costs. Regional availability also influences selection - some high-performance variants require extended lead times from specialized suppliers.
Ever wondered what keeps a current transformer (CT) safe during high-voltage operations? The answer lies in its insulation system. Acting as a silent guardian, insulation prevents electrical breakdown by isolating the primary winding (carrying the measured current) from the secondary winding (connected to instruments).
CT insulation typically uses materials like epoxy resin, oil-impregnated paper, or polymer films. These substances withstand extreme temperatures and voltage stress, ensuring accurate signal transfer while blocking dangerous surges. In outdoor units, silicone rubber or porcelain coatings add weather resistance.
Without robust insulation, CTs risk short-circuiting, data errors, or even explosions. Regular insulation resistance tests are critical—degradation from moisture, heat, or aging compromises safety. Next time you rely on a CT, remember: it’s not just coils and cores doing the work. That invisible insulation layer? It’s the unsung hero keeping power systems grounded. Literally.
These IEC (International Electrotechnical Commission) ratings define a transformer’s thermal endurance—how well its insulation handles heat without degrading.
IEC 60076 categorizes insulation into classes based on maximum allowable temperatures. Class A (105°C) uses materials like cellulose, common in small, low-cost units. Class B (130°C) employs mica or resins for industrial gear. For extreme heat, Class F (155°C) and Class H (180°C) leverage silicone or glass fibers, ideal for heavy-duty applications like mining or steel plants.
Higher classes mean longer lifespan under stress, but overloading beyond ratings risks insulation breakdown—think cracks, leaks, or fires. Always match the class to operational demands. Pro tip: Regular thermal imaging spots early wear. Ignore these codes, and your transformer’s reliability might just melt away.
Transformers keep the world powered, but what keeps them reliable? Enter IEC standards—the universal playbook ensuring these giants perform safely and efficiently. The cornerstone, IEC 60076, covers everything from testing methods to environmental resilience.
Think of it as a transformer’s DNA: IEC rules define insulation class limits (like Class A or H), loss benchmarks, and short-circuit withstand capabilities. Standards also enforce strict safety protocols—noise levels, temperature rise thresholds, and fire resistance. For renewable energy systems, IEC 61869 extends guidelines for grid-compatible designs.
Ignoring IEC specs? Risky business. Non-compliant units often fail under load, spike maintenance costs, or flop in global markets. Pro tip: Look for IEC certification when sourcing transformers—especially for wind farms or smart grids. It’s not just paperwork; it’s proof your equipment won’t quit when the grid gets ugly. Stay wired to the rules, or get left in the dark.
The main difference between IEEE and IEC standards lies in their scope of application and specific fields.
Scope of application and specific fields
IEEE: IEEE (Institute of Electrical and Electronics Engineers) is mainly committed to the development and research of electrical, electronic, computer engineering and science-related fields. It has formulated a large number of industry standards in the fields of aerospace, information technology, power and consumer electronics, and has a wide influence.
IEC: IEC (International Electrotechnical Commission) focuses on the formulation of international standards in the field of electrical and electronic. Its standards cover all aspects from basic electrical components to advanced electronic systems, including wires and cables, power systems, automation equipment, household appliances, etc., and have globally recognized authority.
Historical background and organizational structure
IEEE: Founded in 1963, it was formed by the merger of the American Institute of Electrical Engineers (AIEE) and the Institute of Radio Engineers (IRE). IEEE is a non-profit scientific and technological society with members in nearly 175 countries around the world, and the literature published accounts for nearly one-third of the global electrical and electronic engineering fields.
IEC: Founded in 1906, it is the world's oldest international electrotechnical standardization organization. IEC and ISO are technically and financially independent, but according to the 1976 agreement, IEC is responsible for international standardization in the electrical and electronic fields, while ISO is responsible for other fields.
Standard setting and influence
IEEE: The IEEE Standards Association (IEEE-SA) is responsible for its standardization work and has developed a large number of technical standards involving aerospace, computers, telecommunications, biomedicine, electricity and consumer electronics. These standards have played an important role in the development of global science and technology.
IEC: IEC standards are globally recognized and authoritative and are widely used in international trade and multinational companies. Its standards focus on the global commonality and mutual recognition of products, ensuring the safety and interoperability of electrical and electronic products.
1. Qualified standard of transformer insulation resistance
According to the provisions of the International Electrotechnical Commission (IEC) and national standards, the standard range of transformer insulation resistance should generally be greater than 100 megohms. However, this standard is not static, and it will vary according to factors such as the type of transformer, rated voltage, and operating environment.
Taking power transformers as an example, at 20°C, the insulation resistance of transformers of 10KV and below should be greater than 300 megohms; while the insulation resistance of transformers of 35KV should be greater than 400 megohms. These standards ensure that the transformer can maintain sufficient insulation performance in various working environments to prevent current leakage and electrical failures.
2. Factors affecting insulation resistance
The size of insulation resistance is affected by many factors, including the design of the transformer, the properties of the insulation material, the conditions of the working environment, and the service life. Among them, temperature and humidity are the two most significant influencing factors.
Generally speaking, insulation resistance decreases with increasing temperature. This is because the increase in temperature will increase the conductivity of the insulating material, thereby reducing its insulation performance. Therefore, the insulation resistance of a transformer operating in a high temperature environment may be lower than the value at normal temperature.
Humidity is also an important factor affecting insulation resistance. The presence of moisture will cause the dielectric strength of the insulation material to decrease, thereby reducing the insulation resistance. Therefore, the insulation resistance of a transformer operating in a humid environment may be affected.
The main international quality standards for transformer insulation paper include:
IEC 60450: This is a standard developed by the International Electrotechnical Commission (IEC) covering the method for measuring the average viscosity of new and used electrical insulation papers.
JIS C2300-3-1: This is part of the Japanese Industrial Standards (JIS) and specifies the standards and test requirements for cellulose papers for electrical purposes, especially electrical insulation papers.
SANS 6281-1: This is a standard of the South African Standards Organization (SANS) for test methods for oil-impregnated paper insulated cables, especially for insulating and semi-conducting papers.
The quality standards of transformer insulation paper mainly include the following aspects:
Physical performance standards:
Thickness and width: The thickness and width of transformer insulation paper need to meet specific standards. For example, the standard thickness of 500kV transformer interturn insulation paper is 75μm, 125μm, 60μm and 90μm, the roll width is 625±5mm, and the roll diameter is 550～650mm.
Tensile strength and transverse tearing degree: These indicators need to meet certain standards to ensure that the insulation paper is not easily damaged when subjected to external force.
Conductivity: The conductivity of the water extract of the insulation paper needs to meet the regulations to ensure that its conductive performance meets the requirements.
Power frequency breakdown strength: This is an important indicator to measure the ability of insulation paper to withstand electrical breakdown.
Chemical performance standards:
Moisture content: The average moisture content of transformer insulation paper needs to be measured by frequency domain dielectric spectroscopy to ensure that its dryness meets the requirements.
Ash content and ether extract content: These indicators reflect the chemical composition and purity of the insulating paper and need to be controlled within a certain range.
pH value: The pH value of the water extract of the insulating paper needs to be within a certain range to ensure its chemical stability.
Other performance standards:
Heat resistance grade: The insulating paper needs to be able to withstand the high temperature generated during the operation of the transformer, and usually has different temperature resistance grade requirements.
Mechanical properties: Including tensile strength, degree of polymerization, etc., these indicators reflect the mechanical strength and stability of the insulating paper.
Waterproofness and water absorption: The insulating paper needs to have good waterproof performance and low water absorption to prevent moisture from affecting the insulation effect.
1. Appearance quality
First, we can judge the quality of insulating paper by its appearance quality. The surface of insulating paper is flat and smooth, without defects such as bubbles, wrinkles, cracks, burrs, etc., and the color is uniform and there is no color difference; while the surface of inferior insulating paper is flat and of poor quality, with various defects and uneven color.
2. Thickness uniformity
Secondly, we can judge the quality of insulating paper by its thickness uniformity. Insulating paper with uniform thickness will not have uneven thickness; while inferior insulating paper will have uneven thickness.
3. Compressive strength
The compressive strength of insulating paper is also an indicator to judge its quality. Good insulating paper can withstand pressure, while inferior insulating paper is very prone to breakdown.
4. Porosity
The diaphragm rate of insulating paper is also an important factor affecting its performance. Good insulating paper has a lower diaphragm rate, while poor insulating paper has a higher diaphragm rate, which easily leads to a decrease in insulation performance.
5. Thermal stability
The performance of insulating paper in high temperature environment also needs to be considered. Good insulation paper can maintain stable performance in high temperature environment, while inferior insulation paper is prone to aging, deformation and other phenomena.
6. Manufacturer
Finally, we can also judge the quality of insulation paper by the manufacturer of the insulation paper. Generally speaking, the insulation paper produced by large manufacturers has higher quality, while the insulation paper produced by small manufacturers has relatively poor quality.
There are several ways to find a reliable transformer insulation paper supplier:
Search on online platforms: You can search for transformer insulation paper suppliers through online platforms such as Alibaba. These platforms provide a lot of supplier information, which can help you screen out reliable suppliers.
Check supplier qualifications and certifications: Choosing qualified and certified suppliers can ensure product quality and service reliability. For example, Xuchang Chengrui Insulation Material Factory Co., Ltd. is a qualified enterprise that supplies a variety of transformer insulation papers with excellent heat resistance and excellent mechanical properties.
Reference user reviews: Check other users' reviews and feedback to understand the supplier's service quality and product quality.
Investigate the supplier's production capacity and quality control: Choose a supplier with advanced production equipment and a strict quality management system.
Chinese transformer insulation paper suppliers are reliable in the international market. Chinese transformer insulation paper suppliers have performed well in the international market and have high market recognition and competitiveness.
China is one of the world's largest insulation material production bases, with a complete supply chain and short delivery cycle, suitable for large-volume order needs.
Many China Transformer insulation paper manufacturers have long been OEMs or partners for international giants such as ABB, Siemens, and Schneider, and are familiar with international standards and trade rules.
1. Clarify the needs and compliance requirements
Determine the technical specifications
Clarify the material (such as Nomex®, DMD, Tufquin, etc.), thickness, temperature resistance grade (such as A-E grade), dielectric strength, size and other parameters of the insulation paper.
Confirm whether it is necessary to comply with international standards (such as IEC 60641, UL certification, EU CE certification) or target country-specific standards (such as US NEMA standards).
Study the regulations of the importing country
Check the import policy of the target market: whether energy efficiency certification, environmental protection requirements (such as RoHS, REACH), tariff rates, etc. are required.
Contact the local customs or hire a customs clearance agent in advance to understand the document requirements and potential restrictions.
2. Find reliable Chinese suppliers
Supplier channels
Online platforms: Alibaba International Station, Made-in-China, Global Sources, screen "Gold Supplier" or certified merchants.
Industry exhibitions: Participate in the China International Electric Power Equipment Exhibition (EP China), Canton Fair (Electromechanical Products Zone), etc., and directly contact the factory.
Industry association recommendation: Get a list of companies through the China Electrical Equipment Industry Association (CEA) or the Insulation Materials Professional Committee.
Supplier audit
Verify production qualifications: business license, ISO 9001 quality management system certification, product test report (such as SGS, TUV).
Require samples for laboratory testing (such as breakdown voltage, aging resistance) to ensure compliance with technical standards.
Visit the factory on site (or entrust a third-party agency) to evaluate production capacity, quality control process and delivery capabilities.
3. Negotiation and contract signing Trade terms
Clear price terms (FOB/CIF/DDP), determine the division of responsibilities and cost bearing (freight, insurance).
Agree on the minimum order quantity (MOQ), packaging method (moisture-proof, shock-proof), and delivery cycle.
Payment method
● Common methods: T/T (telegraphic transfer, 30%. advance payment + 70%. see copy of bill of lading), L/C (letter of credit, required to be guaranteed by a bank).
● Risk control: Use third-party guarantee (such as Escrow) or insure trade credit insurance.
● Legal Terms:Specify the handling of quality disputes (such as third-party re-inspection), liquidated damages clauses, and force majeure exemption.
It is recommended that a professional lawyer review the contract to avoid ambiguous terms.
Logistics and customs clearance
Transportation arrangements
Choose sea transportation (full container FCL or less than container LCL) or air transportation according to the volume and timeliness.
Entrust a freight forwarder to handle booking, packing, and document preparation (such as bill of lading, packing list, commercial invoice).
Customs clearance document preparation
Required documents:
● Commercial Invoice
● Packing List
● Bill of Lading
● Certificate of Origin (CO or Form E, if tariff concessions are required)
● Test report/certification documents (such as UL certificate)
● Special documents: Some countries may require import licenses or health quarantine certificates.
● Customs clearance at the port of destination
Provide documents to the customs clearance agent in advance, pay tariffs (if applicable), and cooperate with customs inspections.
Quality Control and After-Sales
Arrival Inspection
Sampling at the port of destination or warehouse, comparing sample specifications, and sending to a third-party laboratory for testing if necessary.
If quality problems are found, make claims or return goods according to the terms of the contract.
Establish long-term cooperation
Long-term framework agreements can be signed for high-quality suppliers to lock in prices and production capacity.
Regularly evaluate supplier performance (on-time delivery rate, qualified rate).
Risk Avoidance Suggestions
Intellectual Property
Avoid purchasing infringing products (such as counterfeit DuPont Nomex®) and require suppliers to provide material authorization certificates.
Exchange Rate and Taxation
Use foreign exchange forward contracts to lock in exchange rates and reduce volatility risks.
Rationally use free trade agreements (such as RCEP) to reduce tariff costs.
Supply Chain Redundancy
Develop backup suppliers to avoid out-of-stock situations due to emergencies (such as epidemics and trade frictions).
Chinese suppliers are highly flexible in the field of transformer insulation paper customization, but risks need to be reduced through technical communication, sample verification and contract constraints before cooperation.
Give priority to suppliers with customized cases, conduct on-site inspections of suppliers' cutting equipment, and ensure production capacity matching.
The following aspects are needed to carry out the transformer insulation paper business:
Market demand analysis: First, a detailed analysis of the market demand for transformer insulation paper is needed. Understand the current market demand for insulation paper of different specifications and performances, as well as the future market growth trend. Information can be obtained through market research, communication with relevant companies, etc.
Technological innovation and patent application: In terms of technology, attention can be paid to how to improve the performance and processing efficiency of insulation paper. For example, develop new insulation paper materials to improve their electrical performance and mechanical strength; optimize processing equipment to reduce losses and costs during processing. In addition, applying for relevant patents can protect technological innovation results and enhance market competitiveness.
Production equipment and raw material procurement: Ensuring a stable raw material supply channel and advanced production equipment is the basis for doing business. Select high-quality raw materials, such as high-purity insulation wood pulp, to ensure the stability and reliability of the product. At the same time, introduce or make efficient processing equipment to improve production efficiency and product quality.
Quality control and standardization: Establish a strict quality control system to ensure that the insulation paper produced meets relevant standards and customer requirements. Standardize production processes and product testing methods to improve product consistency and reliability. The trust and market competitiveness of products can be improved through international standards such as ISO certification.
Marketing and Customer Service: Develop effective marketing strategies, including product promotion, customer service and after-sales support. Establish a complete customer service system to respond to customer needs and solve problems in a timely manner. Expand market influence by participating in industry exhibitions and establishing sales networks.
Cooperation and Alliance: Seek cooperation with transformer manufacturers and power equipment companies to provide customized solutions. Through technical cooperation and strategic alliances, jointly develop new products and markets to achieve mutual benefit and win-win results.
Transformer interlayer insulation refers to the insulation measures between different layers of windings in the transformer. The working principle of the transformer depends on the turns ratio. If a short circuit occurs between layers, the turns ratio will change, causing the transformer to work abnormally. Therefore, interlayer insulation is very important.
Prevent current leakage: The high-voltage part and the low-voltage part in the transformer need to be electrically isolated to prevent current from flowing from the high-voltage part to the low-voltage part, causing electric shock or other safety problems. Insulation materials can effectively prevent current leakage and ensure the safe operation of the transformer.
Reduce energy loss: In the transformer, current passes through components such as coils and cores, generating resistance and hysteresis losses. Insulation materials can reduce these losses and improve the efficiency of the transformer. In addition, insulation materials can also reduce the noise and vibration of the transformer and improve the stability of operation.
Protect the transformer from environmental influences: During operation, the transformer may be affected by environmental factors such as moisture, pollution, and temperature changes, resulting in a decrease in insulation performance. Good insulation materials can effectively resist the erosion of these factors, extend the service life of the transformer, and ensure maintenance and overhaul safety: When performing transformer.
When the transformer insulation fails, the following situations may occur:
Short Circuits: Weak insulation lets current “leak,” sparking internal arcs or fires.
● Overheating Hell: Resistance spikes, temperatures soar, and windings melt—like a bad kitchen meltdown, but pricier!
● Oil Breakdown: In oil-filled units, failed insulation contaminates oil, killing cooling power.
● Costly Domino Effect: Explosions, blackouts, or fried equipment nearby.
Worried about your transformer’s health? Insulation resistance testing is key! Here’s a quick guide:
Power Off & Discharge: Always disconnect and ground the transformer for 10+ minutes. Safety first!
Grab a Megohmmeter: Pick the right voltage (1kV-5kV based on specs). Test windings-to-ground and between phases.
Spot Trouble Early: Good readings? Aim for 1000+ MΩ (oil-filled) or 100+ MΩ (dry-type). Low values? Maybe moisture or cracks!
Mind the Weather: Humidity or cold skews results. Test on dry days near 20°C.
Compare & Track: Log readings over time. Sudden drops mean trouble.
Transformers are vital for power systems, but overheating can shorten their lifespan or cause failures. Here’s how to prevent it:
1. Monitor Loads: Avoid overloading. Stick to the rated capacity to reduce stress.
2. Check Cooling Systems: Inspect fans, radiators, or oil levels regularly. Clean dust-clogged vents to ensure airflow.
3. Control Ambient Temperatures: Install transformers in well-ventilated areas, away from heat sources. Use enclosures with cooling fans if needed.
4. Inspect Insulation: Degraded insulation increases resistance, generating excess heat. Schedule routine dielectric tests.
5. Watch for Leaks: Oil leaks reduce cooling efficiency. Fix cracks promptly and top up oil as required.
Proactive maintenance and smart load management keep transformers running efficiently.
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