Distribution Transformer

Distribution Transformer

PP Industries manufactures a wide range of distribution and medium power transformers. These transformers can be free breathing or hermetically sealed. Conventional transformers are fitted with a conservator with breather for free breathing, while hermetically sealed are without breathing with bolted cover. Our transformers come with the features reliability, durability and efficiency required in utility for industrial and commercial applications. Our oil-filled transformers match the international standards in their designs and are made in accordance with the most demanding industrial use. Transformers can be placed for both indoor and outdoor applications and can be provided with off-load and on-load tap changers.

Applicable standards : IEC / IS / BIS
Range : 5kVA – 2500kVA,
Insulation level : 12KV / 24KV / 36KV

  • Single Phase / Three Phase
  • Indoor / Outdoor installation
  • Conductor : Copper or Aluminium as per customer requirement
  • Core : CRGO / Amorphous as per customer requirement
  • 3 D Core type can also be supplied
  • CSP ( Completely Self Protected ) feature can be provided up to 400kVA
  • Maximum ambient temperature : as per customer’s specification
  • Top oil Temperature rise : as per customer’s specification
  • Average winding temperature rise : as per customer’s specification
  • Hermetically sealed type (with gas cushion / fully filled) / Conventional type
    (with Conservator)
  • Colour : as per customer’s requirement
  • Cooling : ONAN/ONAF as per customer’s requirement
  • Cooling arrangement : Corrugation or Pressed Steel Radiators
  • On Load Tap Changer with RTCC & AVR, can be provided above 500kVA, if
    required
  • Safety devices can also be provided upon request
  • Other optional fittings as required can be provided upon request

Concept of “Completely Self Protected” (CSP) feature in Distribution Transformers

CSP technology is more known for high-performance distribution transformers which mitigate the operation and maintenance problems associated with conventional transformers. CSP technology enables a transformer to protect itself from secondary faults, lightning protection, persistent severe overloads and provides visual warning of the overload conditions. CSP technology also protects the distribution system to which it is connected, in case of its failure. This means, that in case of failure of the transformer, it gets isolated from the system.

Applicable Standards : IEC / IS
Range : Single Phase:- 5kVA-167kVA, Three Phase:- 10kVA-400kVA
Insulation level : 12KV / 24KV /36 KV


Components and benefits of the CSP System


CSP System has four essential components. They are:
–   Oil immersed Circuit Breaker for overload and secondary fault protection

  • Signal Light for indication during overload condition on transformer
  • HV Fuse for over-current, protection by isolating a failed transformer from the system
  • Surge Arrestor

Oil Immersed Secondary (Low Voltage) Circuit Breaker


The oil-immersed circuit breaker is installed on the secondary (low voltage) side of the transformer. It provides the entire over current protection to the transformer and responds to secondary faults external to the transformer by tripping and prevents any thermal damage occurring to the transformer. Besides protecting from secondary fault, the breaker also provides thermal protection to the transformer. It is an electro-mechanical device with three major elements. These elements are:

  • Temperature sensing through the use of bimetallic strips which are built into the breaker such that the load current flows through them. The bimetallic strips responds thermally to the temperature of the transformer oil and also to the temperature changes created by the flow of the load current through them.
  • Latching and tripping functions
  • The signal light latch
  • The emergency control assembly
  • The magnetic trip device
  • It works as Current interrupter

Signal Light indication


The signal circuit is mechanically connected to the circuit breaker latching and bimetal systems through an auxiliary contact. A signal light is mounted on the wall of the transformer tank. It gives a visual external indication when the transformer oil temperature reaches a specified pre-set value of temperature during an overload condition. Once the signal light glows then it can be turned off only by manually operating the external handle of the circuit breaker.


Primary (High Voltage Fuse) Expulsion Fuse for System Protection


In a CSP transformer, the primary fuse is placed in oil and connected in series with the primary winding. This expulsion fuse is to protect that part of the electrical distribution system, which is ahead of the transformer from faults which occur inside of the distribution transformer. If a fault occurs in the windings or some other part of the transformer, it will cause abnormally large currents to flow, resulting in the fuse to melt open and clear the circuit. Thus, the fault is limited only to those customers who are served by this particular transformer and service is maintained on the rest of the system.


Surge Arrester


The surge arrester are mounted near to the high voltage bushings to shorten the ground lead connection between the arrester and the transformer reducing the lightning impulse voltage stress on the transformer winding. The surge arrester diverts the flow of surge to earth by changing its impedance characteristics from high resistance to low resistance.


Introduction to Amorphous Core


PP INDUSTRIES has set up state of the art amorphous metal core transformer manufacturing facility by importing the latest amorphous metal cores manufacturing equipment. This plant has the latest equipment in India to produce energy efficient amorphous metal transformer cores that are annealed under absolute inert atmosphere to get at most lower losses thereby enhancing the energy savings in comparison with the similar manufacturing facilities in India.

Amorphous metal exhibits a unique random molecular structure unlike the rigid grain structure of the silicon steel. This, in turn, enables easy magnetization & demagnetization, thereby reducing hysteresis loss. Further processing of amorphous metal in very thin lamination (approximately 1/10th of silicon steel lamination thickness) enables significant reduction in eddy current losses.


Advantages of Amorphous Metal Transformers


  1. The thickness of Amorphous Metal is 0.025 mm against CRGO silicon sheet steel thickness 0.23-0.3 mm. Lesser thickness in sheet results in lower eddy current loss.
  2. Random molecular structure of amorphous metal causes less friction than CRGO when a magnetic field is applied. This allows easy magnetization and demagnetization significantly lowers hysteresis losses, thus amorphous core significantly reduces core losses which is about 65-75%.
  3. Saves energy and therefore reduces greenhouse gases and other pollution.
  4. Excellent option to reduce distribution losses and improve efficiency.
    Superior electrical performance under harmonic condition.
  5. Possible to improve power quality and mitigate harmonics.
  6. Lower temperature rise, slower deterioration of insulations and hence longer life.
  7. Increase in use of power electronics has resulted in considerable amount of higher harmonics distortion in electrical power system.Higher frequency harmonics lead to increase in transformer core losses whereas amorphous alloy provides lower loss under high frequency.
  8. Easy for repair and replacement of coils.

UNIT I

A-16 New Focal Point, Dabwali Road
Bathinda (Punjab) – 151001, INDIA
0164-2284935

UNIT II

C-11 Ind. Growth Center, Mansa Road
Bathinda (Punjab) – 151001, INDIA
0164-2970274