The power= Voltage*current*power factor... So when the
power factor is equal to or naer 1 the input voltage and
curret is fully utilised.. so losses..But we can't made the
Power Factor more than 1 in Practical life..
Power factor is cosine angle between Voltage and
current.Suppose a alternator of capacity 5000KVA is
operated at unity powerfactor,then it means it can supply a
maximum load of 5000KW load (KW=KVA*P.F).If a same
alternator is operated at 0.8 p.f ,then it can deliver only
4000KW Which means the alternator was loaded maximum.To do
maximum loading of alternator then its power factor has to
be unity or close to unity.
If power factoris above unity, then -ve KVAr itself acts
as a load causing more current to draw from mains Which
leads to heating and also losses.
power factor will be unity when Kw(real power)=KVA(reactive power).i.e P.F=1 ,Now if P.F >1 means reducing KVA ,so one point comes only Kw flows through the line.
Another way power = VI(cos@) ,where cos@ is P.F & @ is angle between voltage and current . so Power =VI when @=0 ,Power =0 for @=90 ,power = -VI for @=180. That means if phase angle between V & I is vary so power delivered to the load will be vary.So pure real power flow only if cos0=1.Means V&I in phase.
Power = 1.734 x V x Ix cos@
Say the power factor is 1 unity.
P=1.734x400x1x1=698.2watts. This much power need to send
from Power statin to do some work. The energy meter will
read the unit as same for this value. But if the power
factor is less or more say 0.8
P-1.732x400x1x.8=554.24watts. This much watts only will
read the meter. Remaining amound send from power station
willnot in calculated and is in losses.Remaining around 150
watts loss in same work.Thats why EB insisting to maintain
unity instead of lagging or leading.
power factor can never be more than one,and if is one then
the load is purely resistive,so all electrical energy being
metered is what is actually consumed by the load,i think
there isnt the effect of unity pf and if i could have been
forced to give an answer i could simply say"the effect of
unity pf is less electrical energy demand for a particular load"
The power factor of an AC electric power system is defined
as the ratio of the real power flowing to the load to the
apparent power in the circuit, and is a dimensionless
number between 0 and 1 (frequently expressed as a
percentage, e.g. 0.5 pf = 50% pf). Real power is the
capacity of the circuit for performing work in a particular
time. Apparent power is the product of the current and
voltage of the circuit. Due to energy stored in the load and
returned to the source, or due to a non-linear load that
distorts the wave shape of the current drawn from the
source, the apparent power will be greater than the real power
Maintaining unity power factor reduces losses in
distribution and in switchgear system not in actual power
consumption. If we maintain the power factor above 1 there
will be more losses in distribution transformers and
capacitors(which are used to increase PF). The capacitive
power reduces the inductance power in transformer thereby
increasing the losses.
We operate a 10 Mw facility and we have been experiencing
several trips due to fluctuations on the MVAR? We have
checked all issues related to the AVR and we have found all
OK? Can anyone help us? The grid voltage, internal voltage,
all regular parameters look ok. MVAR fluctuate and there it
goes the unit? What could be happening? Thanks!