On Load Tap Changer Transformer（OLTC）

On Load Tap Changer Transformer（OLTC）overview

  - Product actual measurement is better than GB and IEC standards, CB CCC KEMA SASO certification
  - More than 50 countries and regions around the world run verification of high reliability
  - It is mainly used in10KV 11KV 13.8KV 15KV 20KV 22 KV 30KV 33KV 34.5 35KV distribution network of State Grid, power supply and distribution system of industrial and mining enterprises and civil buildings
  - Executive standard: IEC 60076 series, IEC 6013, IEC 60214-1, IEC 60296;GB1094 series, GB/T6451-2015, GB/T7597-2007, etc

On Load Tap Changer Transformer（OLTC） advantage

> Leading technology
 - High voltage copper strip winding technology, improve lightning resistance
 - Low voltage copper foil winding technology, high quality A class insulation material insulation
 - Small magnetic leakage, high mechanical strength, strong resistance to short circuit
 - Core 45° fully oblique joint stepping laminated structure

> The shell
 - Japanese mitsubishi laser cutting machine and numerical control punching, reducing, folding and other equipment to ensure the accuracy of processing
 - ABB robot automatic welding, laser detection, to avoid leakage, pass rate of 99.99998%
 - Electrostatic plastic spray treatment, 50 years do not take off the paint (coating corrosion resistance within 100h, hardness ≥0.4)
 - Sealed structure, maintenance-free, normal operation life of more than 30 years

> The iron core
 - The iron core is made of high quality cold-rolled grain oriented silicon steel sheet with mineral oxide insulation (from Baosteel and WISCO of China).
 - By controlling the cutting and stacking process of silicon steel sheet, the loss level, no-load current and noise can be minimized
 - The iron core is specially reinforced to ensure the structure of the transformer is firm during normal operation and transportation

> Winding
 - The low voltage winding is made of high quality copper foil with excellent insulation resistance
 - The high-voltage winding is usually wound with insulated copper wire, using the technology patented by hengfengyou electric
 - It has very good ability to bear radial stress caused by short circuit

> High quality material
 - Baosteel and WISCO produce silicon steel sheets
 - China's high quality oxygen free copper
 - CNPC (Kunlun Petroleum) High quality transformer oil (25#)

> Other Notes
 - The low voltage outlet terminal is tin-plated copper bar
 - High voltage outlet terminals are ring - type tin-plated bolts
 - Default OLTC（on load tap changer）

> Patent technology
 - Thanks to the patented technology of "ultra-low loss energy-saving power transformer" of Hengfengyou Electric, the material can be saved by 5%, and the loss of the transformer can be reduced by 10-20% compared with similar products in the market, which is more energy saving and environmental protection.



Conditions of use

  - Altitude less than 1000m, air temperature -25℃~40℃, humidity less than 90% (+25℃)
  - The vertical incline should not exceed 5°, there is no severe vibration place, and the outdoor wind speed should not exceed 35m/s
  - No gas or conductive dust that seriously affects the insulation of the transformer;No explosion hazard, no corrosion of electrical components
  - If the above normal operating conditions are exceeded, customers can customize the solution with our company


On Load Tap Changer Transformer（OLTC） parameters

  - Input voltage: 10KV 11KV 13.8KV 15KV 20KV 22 KV 30KV 33KV 34.5 35KV
  - Output voltage: 0.4kV 0.415kV 0.416kv 0.420kv 0.440kv
  - Capacity: 160-25000 kva
  - Frequency: 50HZ/60HZ
  -Voltage regulation mode:OLTC（on load tap changer）
  - Remark: voltage, capacity, frequency, connection group and loss can be customized according to customer requirements

1. What is an On-Load Tap Changer (OLTC) transformer?
   An OLTC transformer is a power transformer that allows voltage regulation by changing tap positions while the transformer remains energized and under load.

2. How does an OLTC transformer work?
   The OLTC adjusts the transformer's turns ratio by mechanically or electronically switching between different tap positions, maintaining a stable output voltage despite input fluctuations.

3. What are the main advantages of OLTC transformers?
   OLTC transformers provide continuous voltage regulation, improve power quality, reduce downtime, and enhance grid stability by adjusting voltage without interrupting the load.

4. What are the common types of OLTC mechanisms?
   The two main types are resistive (switches taps with a transition resistor) and reactive (uses a reactor to limit current during switching).

5. What maintenance is required for OLTC transformers?
   Regular inspections, oil testing, contact resistance checks, and mechanical wear assessments are essential to ensure reliable operation.

6. What are the typical applications of OLTC transformers?
   They are used in power grids, industrial plants, renewable energy systems, and substations where precise voltage control is necessary.

7. What are the signs of OLTC failure?
   Common signs include abnormal noises, excessive heating, erratic voltage regulation, increased contact resistance, and oil degradation.

8. How often should OLTC tap positions be changed?
   Tap changes depend on load and grid conditions but should be monitored to avoid excessive mechanical wear. Frequent unnecessary switching should be minimized.

9. Can OLTC transformers be retrofitted with modern controls?
   Yes, older OLTC systems can be upgraded with digital monitoring, motor-drive controls, and remote operation capabilities for better performance.

10. What safety precautions are needed when working with OLTC transformers?
    Always de-energize the transformer before maintenance, follow lockout/tagout procedures, wear protective gear, and ensure proper grounding to prevent electrical hazards.