14 June 2019

Daily Renewable Power Generation In India


Renewable Power Generation Report
How do you know daily renewable power generation in India?
Just click on www.cea.nic.in

Disadvantages of Low Power Factor


The three phase line current IL = P / ( √ 3 ) VL Cos ะค
As the power factor is low, the load current is high and vice versa. The low value of power factor affects following ways.

Transformer

Construction of Cable


The cable consists of following main parts.

Core of Cable

  • The core of the cable is made of aluminum / copper. 
  • It is lies in the center part of cable. 
  • However the number of core depends upon the type of cable either single phase or three phases. 
  • There are three core of three phase supply system and four core for three phases , four wire system. 
  • The 3.5 core cable means that the cross section of neutral / fourth cable is one half that of main core.




Insulation

  • The core is provided with insulation and the thickness of insulation depends upon operating voltage of the cable. 
  • There are following materials used for cable insulation : 

  1. Varnished cambric
  2. Poly vinyl chloride ( PVC )
  3. Paper
  4. Cross linked polyethylene ( XLPE )
  5. Vulcanized bitumen

Metallic sheath

  • The insulating material is protected by moisture, gases and other harmful liquid in a soil by metallic sheath. 
  • It is provided over the insulation. 
  • It protects the insulation against mechanical damage. 
  • It is made of lead / lead alloy. 
  • The aluminium is also used as metallic sheath because of higher mechanical strength, less cost and low weight as compared to lead sheath.

Bedding

  • The mechanical sheath is made of metal therefore it has possibility of corrosion and mechanical injury. 
  • The bedding is made of fibrous material like jute / hessian tape and protects the cable from corrosion and mechanical injury.

Armouring

  • When cable is handling and laying in the underground, it is protected from mechanical injury by armouring. 
  • It consists of two / three layers of steel wire / steel tape.

Serving

  • It is outer most layer of the cable. 
  • It is used over the armouring. 
  • The function of serving is to protect armouring against atmospheric conditions.
Finally, the inner most layer to outer most layer of cable is
  • Core
  • Insulation
  • Metallic sheath
  • Bedding
  • Armouring
  • Serving
You may also like :

9 June 2019

Technical Specification of Three Phase Transformer And Fittings

The following technical Specification is provided by the Manufacturer of transformer.
  • Name of Manufacturer
  • Service
  • kVA rating

Transformer Testing : Type Tests, Routine Tests and Special Tests

Testing of Transformer

  • The following types of type test, routine test and special tests are performed on the power transformer. 
  • These tests are to be performed at ambient air temperature below 50 degree centigrade. 

Standard KVA Rating of Three Phase Power Transformer

Rated kVA

  • The rated kVA is related to the product of rated voltage, rated current and appropriate phase factor as given below.

Number of Phases
Phase Factor
1
1
3
1.73

8 June 2019

Transformer Name Plate As Per Indian Standard

The following information is displayed on the transformer name plate.
  • Kind of Transformer
Auto transformer, Booster transformer etc.
  • Number of Standard ( IS code )