Zhejiang Tenglong Electrical Apparatus Co., Ltd. which was founded in 1978 is located on Sanmen bay of East China Sea. It is one of the earliest Companies in designing and manufacturing tap-changers for transformers. With the abundant experience in design and manufacture of transformer components for years, and the Combinations of High-Scientific theory and Modern design theory in practice, as a result Tenglong has obtained lots of patents for those reasons we have mentioned above. And this is also one of the key reasons why Tenglong has excellent quality products and becomes the main supplier for transformer tap-changers in China. People oriented and honesty is the everlasting motto for all Tenglong People. And Tenglong people are famous for their hard struggle and creative minds, thus enable Zhejiang Tenglong Electrical Apparatus Co. Ltd. to walk on the right track to the sustainable development.

Tenglong company with a registered capital of 13,000,000 RMB, covers an area of 102 acres. Our company has equipped with advanced production and test facilities. It also has strong technical force in design and manufacture of tap-changer.The annual output of Tenglong is often on the precedent place among all tap-changer manufacturers in china. Furthermore, Tenglong passed ISO quality management system, environment management system and occupation healthy safety management system. For the excellent quality of our products, Tenglong tap-changers have been selling well in domestic and abroad, each year we would have certain quantities of tap-changer sold abroad and our products has gained more and more reputations among our customers abroad. At the same time, Zhejiang Tenglong has awarded the prize of Grade AA "Integrity on contract and credit" of Zhejiang Industrial and Commercial Enterprise unit,‘，Sci-tech Enterprise of Zhejing Province", "High- tech Enterprise”and so on. 

Company”.We insist on the idea of quality first and customer first, prosperous by quality and succeeding with excellence, manufacturing various special tap-changers for the customer and be a good partner of the transformer factory.

 Tenglong is the trademark of our products, we have more than 40 series and thousands kinds of types. The main products are as follows:

 1 .De-energized tap-changer

(1)De-energized pipe-form and drum-form tap-changer (WDG, WDG+WLG, WSG series)

Its rated voltage is 220kV (highest voltage for equipment 252 kV)and below, rated current 4000A and below with three-phase parallel operation, 1+2 phase or single phase operation, the way of operating are direct or parallel operation on transformer cover, bottom and side.

(2) De-energized cage-form tap-changer (WSL series)

Its rated voltage is 220kV (highest voltage for equipment 252 kV) and below, rated current 3000A and below with various regulating methods can apply hand-operation on the cover or side of the transformer or electrical operation.

(3) De-energized linearity tap-changer (WDT and WST series)

Its rated voltage is 11 0kV (highest voltage for equipment 126 kV) and below, rated current 1 600A and below with various regulating methods.

(4) De-energized tray-form tap-changer (WDP and WSP series)

Its rated voltage is 35kV (highest voltage for equipment 40.5 kV) and below, rated current 400A and below.

(5) De-energized electric cage-form tap-changer (WSLD series)

Its rated voltage is 35kV (highest voltage for equipment 40.5 kV) and below, rated current 2000A and below.

2. Oil-immersed load switch (LBS)

Its rated voltage is 35kV(highest voltage for equipment 40.5 kV) and below, rated current 630A and 315A,equipped with manual，manual and electric operation combination structure, with two and four transform work positions, respectively used for the terminal type and ring type combination transformer，photovoltaic and wind power project transformer.

3. On-load tap-changer

(1)SV series on-load tap-changer

Its rated voltage is 35-66kV(highest voltage for equipment 40.5-72.5 kV), the maximum rated passing current for three- phase tap-changer is 350A or 500A, and they are applied mainly to on -load transformer with rated voltage 110kV.

(2) F series compound on-load tap-changer

Its rated voltage is 35kV (highest voltage for equipment 40.5 kV) and below, rated current 400A and below. The maximum step voltage for 10kV (highest voltage for equipment12 kV) is with voltage class of 1000V and suitable for oil-immersed on-load voltage regulating power transformers.

(3)On-load tap-changer for capacity and voltage regulation

Its rated voltage is 10kV(highest voltage for equipment 12 kV)，applicable to different capacity of oil-immersed transformers ranged from 200(63) kVA to 630(200)kVA.

(4)Compound vacuum type on-load tap-changer

Its rated voltage is 10kV (highest voltage for equipment 12 kV) and below, rated current is 400A and below, applicable to oil-immersed distribution transformers.

(5)Horizontal vacuum permanent magnet on-load tap-changer

Its rated voltage is 10kV (highest voltage for equipment 12 kV) and below, rated current is 63A and below, applicable to oil-immersed distribution transformers.

(6)Dry-type vacuum on-load tap-changer

Its rated voltage is 10kV (highest voltage for equipment 12 kV) and below, rated current is 1 65A and below, applicable to dry distribution transformers.