66kV~110kV oil-immersed powertransformers

Product Structure and Process Characteristics

The oil-immersed power transformers produced by our company are based on the advanced technologies at  home and abroad,and are designed independently according to the characteristics of Chinese urban and rural power  grid.Our  product  performance is better than the GB/T6451 Three-phase Oil-type  Power  Transformer  Technical  Parameters and Requirements,in fullcompliance with JB/T3837 Transformer Product Model Preparation Method,the manufacturing standards of GB/T1094 Power Transformers and the IEC standards recommended by the International  Electrotechnical Commission and GB20052-2020"power transformer limited value of energy efficiency and energy efficiency  level".

The  product  is characterized by low loss,low  noise,anti-leakage and  no suspension core.It  has extraordinary innovation in safety,reliability,economic efficiency and other aspects,so thatit becomes a first-class technical product  in China.The product has the following characteristics:

Iron  Core  of  Transformer:Its iron core  adopts  multi-step  stepping  lap-type  technology,the  laminated  piece  adopts 45°oblique seam hole-free bandage structure,silicon steel sheet adopts advanced longitudinal and horizontal  shear cutting,cutting mouth burr is not more than 0.02 mm.In addition,the advanced iron core stacking station,strict stacking  and  no  pre-stack  yoke  process  fully  guarantee  the  grain  orientation  of  silicon   steel  sheet,effectively  reducing  the no-load loss of the transformer.The iron core adopts high-strength PET polyester banding design,clip structure  adopts  plate  clamp  pieces,thus  reducing  spurious  loss.The  iron yoke  clamper adopts a  unique  clamping  banding  process,fully guarantees the  iron core's clamping degree.At the same time,over years of development,the  mature  technology makes iron core,pull plate,roof beam,side beam and pad become a fim organic whole,and ensures that  their on core sheet is in the best state to resist pressure,thereby reducing the transformer's no-load loss and greatly  lowering the noise of transformer.

Transformer  Winding:The  transformer's   high,medium,low  and  voltage-regulating  coil  shall  wound  on an   insulating  paper tube.Low-voltage winding  mainly adopts spiral structure with axial oil  passage.High and  medium  voltage windings are made by composite wire wrapped by high-strength Dennison paper,which is imported from the United  States,they  can  greatly  increasethe  filing  coefficient  of  transformer's  steel  window,reduce  the  wire's  eddy current loss and circulation loss,and also improve the anti-short circuit capacity of the transformer.There are locking stays (namely reinforced stayslinside and outside the winding.The winding's radial fastening adopts the design of0  margin,which greatly enhances the winding's mechanical strength and short circuit resistance.Meanwhile,the high,   medium and low-voltage windingshall equipped with an oil-oriented structure,which reduces the temperature rise at  the hottest points of winding,thus extending the transformer's service life.The on-load tap changing transformer has  an  independent  voltage-regulating  winding,so  that  the  winding's  ampere  turns  are  more  balanced,the  stability  is  improved,and the instability and deformation are eliminated,thus effectively reducing the transformer's axial power        caused by external short-circuit,and improving the transformer's dynamic stabilityin the case of external fault.

Transformer Body Insulation:The transformer's body insulation structure and winding process are completed in a fully sealed clean workshop,can meet the cleanliness requirements and constant body temperature requirements for high  voltage,ultra-high  voltage  transformers,and  further  ensure  the  cleanliness  and  dryness  of  transformer  body.        Meanwhile,kerosene vapor-phase drying equipment is used to further ensure the cleanliness of the body.The lower pallet and upper pressure plate of the body all dopt electricallaminated wood with high mechanical strength and good electrical performance.The stays and pads in the transformer all have gone through high-precision cutting and rounding  processes,greatly reducing the partial discharge.The steel clamp and steel nails have sufficient strength,the pressure  contact  surface that  connects  pressure  sheet  is  designed  to  be  the  maximum.Support  pads,stays  and  nails  are arranged ina way to make the winding has balanced pressure,and enhance the overallstability.The body adopts overall  package constant-pressure drying process,shortens the assembly time after winding is stabilized.The winding con-  centricity is adjusted,so that the cores will be consistent as much as possible,fully ensure that the coils have equal  reactance height,keep even pressure on the winding,thereby improving each winding's anti-short circuit capability,  In addition,the lower clamp and lower fuel tank adopt a four-week steel positioning,and can be adjusted or locked  through anti-pressure nails;upper beam and upper fuel tank lid adopt epoxy resin curing positioning,so the body can  withstand the impact of variety of transport conditions in the tank,and does not shift when there is axial electric power  in the operation.

Transformer Lead Wire:The transformer's high and medium-voltage tap wires are fixed by a bracketand led to the switch,low-voltage lead copper wire is fixed onto the upper and lower clamps to improve the stability of lead wire.  Besides,the coil binding standards and technological process greatly reduce the transformer's partial discharge.

Transformer Tank:Large and medium transformers adopt bell-type fuel tank structure.Large-scale folding  machine is used for corrugated molding.Various reinforced iron sheets and reinforced boards are cancelled.This not  only greatly improves the mechanical strength of oil tank,but also reduces the leakage caused by welding,increases  the effective cooling surface of the body,and improves the cooling effect.Meanwhile,due to the divergent effect of  corrugated box wall,the noise of transformer is effectively reduced.The seal part of tank is treated with special pro-  cessing,and the whole fuel tank adopts"shot peening'treatment,thus completely removing the oxidized surface of the  box,as well as the sharp corners and welding slag caused by the processing,improving the adhesion of paint,and  making the transformer more beautiful and durable.Radiator and other components are tested and inspected by simu-   lating the field operation in harsh environmental conditions,thus effectively removing the leakage point.All the flange  surfaces are refined,and set slotted position limiting structure.A high-quality oil-resistant,ozone-resistant acrylic  rubber gasket is adoptedto prevent the leakage of thetransformer.In addition,the transformer's upper and lower fuel  tanks can be connected by bolts,and can also adopt seal structure along the upper and lower fuel tanks according to  the  user's  requirements.

Transformer Cooling and Accessories:It generally adopts air-cooled/self-cooled type,and has full-load opera-  tion when the fan starts,andbegins naturally cooling when the fanstops,the load is 67%of fulload.Chip radiatorshall arranged in a reasonable and compact way,fans are generally hung over radiators,blowing in horizontal or vertical  direction.The oil storage tank is generally capsule type,which has an oil-resistant,airtight capsule.It completely  isolates from the oil of transformer from the air,and achieves full sealing.In addition,it can also adopt the expansion  metal corrugated oil storage cabinet (internal oil cabinet or external oil cabinet)made by stainless steel.It is mainte-  nance-free,and has reliable operation.

With advanced technologies,the Company has implemented perfect quality assurance system,adopted reliable  product structure design and advanced technological processes,and ensured that our products have high reliability,low  partial discharge,low loss and low noise.

Technical parameters and characteristics

Technical specification

1.Voltage  rating:66KV~110kV;

2.Voltage regulating   method:on-load voltage regulating,no-load voltage regulating;

3.Rated capacity:630  63000kVA(see the attached sheet,it can be customized according tousers'requirements): 

4.Frequency:50Hz;

5.Number of phases:3-phase;

6.Label of connection group:according to national standards orusers'requirements;                       

7.Short circuit impedance:according to national standards orusers'requirements;                           

8.Application environment:according tonational standards or users'requirements;

9.Cooling method:oil-immersed  self-cooling,air-cooled

Application environment and conditions

1.Device type:outdoor type

2.Ambient temperature:the  maximum temperature+40℃,the  minimum  temperature-30℃

3.Altitude:≤1000 m(The temperature rise should be modified if the altitude is higher than 1000 m) 

4.Relative    humidity:≤90%(25℃)

5.Installation site:places with no corrosive gas and no obvious dirt

Product  model  description

Protection code(generally isnot marked,TH--hot and humid,TA-dry heat) 

High voltage level (kV)

Rated capacity(kVA)

Performance level code(11,or according to user's requirements)

Z:On-load distribution;no-excitation distribution is not marked

S:Three-winding;two-winding  is  not  marked

F:air-cooled;self-cooledis  not  marked

Three-phase

Notes for Customers

Please provide the following parameters when placing an order:

1.Product  modelo

2.Rated  capacityo

3.Voltage  combination  C

4.Voltage  regulation  range

5.Frequency           

6.Label of connection group ◎

7.Short circuit impedance

8.Other:special requirements should be noted.

Product performance parameters

66KV three-phase two-winding no-excitation distribution transformer

66KV three-phase two-winding on-load voltage regulating power transformer

Type 11 of 66kV three-phase two-winding no-excitation distribution transformer

Note 1:When the number of taps and stage voltage remain unchanged,it is allowed to increase the number of  negative taps while reducing the number of positive taps,or increase the number of positive tapswhile reducing the number of negative taps,such as.

Type 11of 66kV three-phase two-winding on-load tap changing transformer

110kV three-phase two-winding on-excitation distribution transformer

110kV three-phase two-winding on-load tap changing transformer

110kV three-phase three-winding no-excitation distribution transformer

110kV three-phase three-winding on-load tap changing transformer

110kV low-voltage 35kV three-phase two-winding no-excitation distribution transformer

Type 11 of 110kV three-phase two-winding no-excitation distribution transformer

Type 11 of 110kV three-phase three-winding no-excitation distribution transformer

Note  1:The capacity ratio of high,medium and low-voltage capacity is(100/100/100)%respectively. 

Note 2:According to the requirements,the label of connection group is YNynOd11.

Note  3:According  to  users'requirements,the  medium-voltage  transformer  can  adopt  the  voltage  value  that  is different from the table or set taps.

Note 4:Step-up transformer should adopt tap-free structure.Taps can be usedif there are operationalrequirements.

Note 5:When the number of taps and stage voltage remain unchanged,it is allowed to increase the number of  negative taps while reducing the number of positive taps,or increase the number of positive tapswhile reducing the number of negative taps.

Note 6:Ifa user wants to buy a transformerwith a short circuit impedance value thatis different from the specified short circuit impedance value in the table,we should discuss the loss and other performance parameters,and specify  the  user's  requirement  in  the  contract.

Type 11 of 110kV three-phase two-winding on-load tap changing transformer

Type 11 of 110kV three-phase three-winding on-load tap changing transformer