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
ACTIVE POWER :
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.
APPARENT POWER :
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.
ELECTRICAL ENERGY UNIT :
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
- 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.