All industrial units are major consumer for electrical energy . Electrical energy cost  is substantial
where the main process is electrical energy based .   

Few basic terms which are used in electrical systems

The active power  is the shaft power required or teue power required for the
application  and it is measured in KW (KILOWATT)

Reactive power is the power  used by  inductive loads like motors  and capacitive loads like capacitor to
create and maintain the electro -magnetic  field  for their working .Its measured  in KVAR.

The vector sum of the active power and the reactive power  make up the total power .This is the power
which is supplied by  the power generating  authority for the user .Its measured as KVA.

Utility bills are based  on no of units consumed by equipments or facility over certain period of time .One
unit of electricity ( 1KWH) is the energy consumption  of 1KW load for 1 hr  continuously.

The ratio of active power ( KW ) to apparent  power (KVA) is called power factor.Which equal to or always
less than 1.

power calculation for  3 phase load

apparent power ( KVA) = 1.732XVOLTAGEXAMPERES/1000
active power ( KW)      =  1.732 XVOLTAGEXAMPERESXP.F/1000

Following ideas can reduce electrical energy consumption  in any manufacturing facility.

  • Provide separate lighting transformer for control of lighting systems.   

  • Locate substation near the load centres to minimize energy losses in cables and also improve
    voltage levels.   

  • Install capacitors with automatic power factor control panel to maintain a power factor of not less
    than 0.9. Install capacitors near the load points wherever possible or at the sub distribution board.
    The best practical method would be to intall capcitors at larger capacity motors and at the
    substation for all other loads.  

  • Identify underloaded motors and examine the possibility of replacing them with the appropriate
    capacity motor or altenatively fix retrofitting devices that are available to save energy.   

  • Identify under-loaded transformers and redistribute the load to achieve optimum loading

  • Select and use energy efficient motors and transformers having less losses, for new installations.
    Where it is economical, it is worthwhile replacing the existing motors/transformers.  

  • Transfer the operation of high capacity loads to lightly loaded shift hours to reduce maximum
    demand to flatten the load curve and maintain a high load factor.  

  • Stagger starting and operation of high capacity motors.  

  • Balance the loads on all three phases within ± 1%, as voltage imbalance results in higher losses.  
  • Optimise  the tariff structure  with  utility  supplier

  • Correct power factor  to at least  0.90 under load condition.

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