Reactive Power Management.

Principle of reactive and energy management

FEATURES :

• All AC electrical networks consume two types of powers:activepower(kW) and reactivepower(kVAr)
• The Active Power P (in kW)is the real power transmitted to load such as motors,lamps,headers,computers,etc.
• The Electrical active power is transformed into mechanical power,head or light.
• The Active Power q (in kVAr) is used only to power the magnetic circuits of machines,motors,and transformers.
• The apparent power s in(KvA) is the vector combination of active and reactive power

TECHNICAL SPECIFICATIONS :

• The circulation of reactive power in the electrical networks has major technical and economic consequences.
• For the Same active power P, a higher reactive power means a higher apparent power.
• The Circulation of active power over time result in active energy in (kWh)
• The Circulation of reactive power over time result in active energy in (Kvarh)
• In an electrical circuit,The reactive energy supplied in additional to active energy
• Power Factor Correction: This is obtained by the connection of capacitor,Which produce reactive energy absorbed by load such as motors.
• The result is reduce apparent power,and an improved power factor P/S' as illustrated in diagram opposite.
• nThe power generation and transmission are partially relived,Reducing power losses and making additional transmission capacity available.

Benefits of reactive energy management

Optimized management of reactive energy brings economic and technical advantages

Savings on the electricity bill:

• Eliminating penalties on the reactive energy and decreasing kVA demands
• Reducing power losses generated in the transformers and conductors of the installation.
• Example:
  Loss Reduction in a 630 kVA Transformer Pw =6,500 W with initial power Factor = 0.7.
  With power factor connection,we obtain a Final Power Factor = 0.98;
  The losses become:3,316 W, ie a reduction of 49%.
  
  Copper loss =(PF₁)/PF₂)² * full load copper loss.
  =(0.7/0.98)² * full load copper loss.
  =(0.7/0.98)²*6500 W
  =3316W
  Savings =6500W-3316w
=3183W

INCREASING AVAILABLE POWER:

• A high power factor optimizes an electrical installation by allowing better uses of components.The powers available at secondary of a MV/LV transformer can therefore be increased by fitting power factor correction equipment on the low voltage side
• The table show the increased available power at the transformer output through improvement of power factor from 0.7 to 1.
• Rated Current: Load DG Side: 1A to 20A (Factory Set)
• interval from EB to DG: After input stable in DG - after 2 Sec
• Example:
  Calculate for additional load in kW that can be connected by improving power Factor.
  
  Load=500 kVA
  Intial PF(cosQ1)=0.7
  Target PF(cosQ1)=0.95
  cosQ1=kW₁/kVA₁
  kW₁=kVA x cosQ₁
  =350 kW
  kW₂=kWA * cosQ₂
  =475 kW
  Additional kW that can be connected=475-350=125kW
  % of additional load=125/350*100=36%