Download Energy Losses in the Electrical Circuits

 Energy
Losses in the Electrical Circuits
Abeco “International” Ltd. V1.2 2010
Motors, lighting systems, wiring, mechanical
terminations, distribution panels, protective devices,
transformers, switchgear, and all end of circuit
equipment experience a variety of resistance increasing
inefficiencies that combine to create an average wattage
loss
•  In a typical industrial facility of from 10% to 25% of total
demanded power
• 
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None of us expected such a large
loss of energy in our companies
Abeco “International” Ltd. V1.2 2010
  The
individual contributing loss
components is a challenging
engineering specialty, requiring
extensive experience and
knowledge of all the factors
impacting the operating efficiencies
of each of these components
Abeco “International” Ltd. V1.2 2010
• 
Current dependent - heat losses:
•  on the Resistance (R)
•  on the Harmonic Distortion
•  on the Power Quality
•  on Reactive Power
Abeco “International” Ltd. V1.2 2010
Losses in AC electrical circuits are dependent on the
sum of all currents and resistance occurring in the
circuit.
Abeco “International” Ltd. V1.2 2010
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These losses are a function of the
length of the electron mean free
path in the metal - wire.
mean free path length depends on
the number of electron collisions
with:
Dislocation
Point defect
injection
Obcy atom
•  elements dependent on metal
properties
•  Impurities in the lattice
•  Lattice imperfections (ie. Dislocations,
point defects)
•  Grain boundaries, grain polarization...
•  elements dependent on temperature Phonons - vibrations of crystal lattice
Phonons
Abeco “International” Ltd. V1.2 2010
• 
Free electron scattering (collision) probability
is proportional to the "space" occupied by the
excited electron to the metal ion orbits
• 
In the excited state “space” occupied is
much, much larger - This means that
decreasing the electron mean free path that
is decreasing conductivity
• 
Just pick up part of the energy of the electron
in the outer orbit of the ion to reduce the
“space” occupied by the ion in metal.
Abeco “International” Ltd. V1.2 2010
Probable locations of the
electron in the ground state
Probable locations of the
electron in an excited state
• 
We use the features of the free electron
and the photon as a particle and transfer
part of the energy of the electron to the
low-energy photon using one of the
Compton scattering effects
•  In addition the Compton scattering effect is
increaseng the wavelength of the electron.
• 
Probability of free electron collision with the
ion in the cross-section of electrical wire,
with and without Power Optimizer ®
Abeco “International” Ltd. V1.2 2010
Compton effect
• 
Electrical properties of metal depend on
its purity and production technology.
• 
After manufacture of the wire is very
difficult to change its electrical
properties.
with Power Optimizer
Metal structure with Power Optimizer®
We can dynamically increase the
density of metal. Interacting metal by
ferromagnetic modulator using PLZT
ceramic properties.
Increasing the density of the metal results
in improved strength, electrical and thermal
conductivity and permeability.
• 
Abeco “International” Ltd. V1.2 2010
Metal structure w/o Power Optimizer®
• 
Lower probability of collisions - less loss of energy,
Less energy loss - less heat,
•  Less heat - lower temperature,
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Lower temperature - lattice vibration smaller
• 
Smaller lattice vibration - lower probability of collisions
• 
Less energy loss - less energy bill
Abeco “International” Ltd. V1.2 2010
• 
Each harmonics current flowing through the
resistance causes heat-losses.
• 
As the harmonic frequency increases,
resistance increases - the skin effect.
• 
Reducing the harmonic content and skin
effect , we reduce the energy heat losses.
Very large impact on losses in the circuit with a fast solid state switches
new instruments for measuring power quality, measure up to 3000 harmonics
Abeco “International” Ltd. V1.2 2010
Harmonic distortion - current [A]
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Because of the influence of the skin effect
upon inductance the resistance is
frequency-dependent
The electromotive force produced in this
way by self-inductance varies both in
magnitude and phase through the crosssection of the conductor, being larger in the
center and smaller towards the outside
The current therefore tends to crowd into
those parts of the conductor in which the
opposing EMF is a minimum; that is, into
the skin of a conductor
Abeco “International” Ltd. V1.2 2010
l cable length,
r conductor radius,
µ0 magnetic field constant,
µr relative permeability,
σ conductivity and
ω angular frequency (ω=2πf)
The wire cross-section
low frequency
F > 1KHz
F > 100 KHz
• 
In the electric motors •  Reduction of self-inductive effect and
stray losses
•  content of some of the harmonic,
reduces the reverse torque of motor
•  reduces the temperature of motor
winding which extends its life time
Abeco “International” Ltd. V1.2 2010
 
Inductive load - draws current has two
components
◦  Real current I supplies Real Power P
[W] to the load - to perform work. loss ∆Pr=I2R
◦  Reactive current Ir supplies Reactive
Power Q[var] to the load - energize
the magnetic field of load (i.e.. motor)
- loss ∆Pre=Ir2R=(Q/U)2R
 
Both currents supply Apparent Power S
[VA] to the load - loss ∆P=∆Pr+∆Pre
Abeco “International” Ltd. V1.2 2010
Reactive Power
 
To get 1 KW of real power if PF = 1,1 KVA
apparent power needs to be transferred
 
To get 1 KW of real power if PF = 0.2,5 KVA
apparent power needs to be transferred
◦  This apparent power must be
transmitted to the load, and is subject
to the usual distributed losses "
Abeco “International” Ltd. V1.2 2010
• 
In addition to reducing energy losses we would increase the
efficiency of conversion of electricity to other energies.
•  mechanical
•  Heat
•  light
Abeco “International” Ltd. V1.2 2010
Abeco “International” Ltd. V1.2 2010
  Is
regular three-dimensional
lattice of ions containing a
large number of electrons that
are free to flow throughout the
whole metal.
Abeco “International” Ltd. V1.2 2010
• 
The movement of charges
constitutes an electrical current
• 
In metals flowing electrical charges =
free electrons
• 
No external electric field applied free
electrons move randomly = no
current flow
Abeco “International” Ltd. V1.2 2010
random move of the electrons
  The
electric field causes the
electrons move opposite to the
direction of the field
  Flow
of the electrons = electrical
current
Abeco “International” Ltd. V1.2 2010
E
Arrenged Flow of Electrones
 
The electric current flow I is
determined in amperes A.
 
I - the amount of electrical charge
passing through the cross-section of
the wire in time.
 
j - current density the amount of
electricity flowing through the wire
cross-section
Abeco “International” Ltd. V1.2 2010
• 
Average speed of electric charges
constituting the current = 1A in the copper
wire with cross section = 1mm2
• 
Cu
•  29 protons and 27 core electrons and 2 - valence
electrons
•  molar mass of copper =63.5 gm/mol density of copper= 9
gm/cm3
•  number of free electrons per mol = 6.02 * 1023/mol , in 1
mm3 =1.7*1020 el/mm3
•  charge in 1 mm3 = 1.7*1020 *1.6*10-19 =27 C/mm3
•  Average speed of charge - 1A = 1C/s then 1/27 mm/s
Abeco “International” Ltd. V1.2 2010
T
Charge density "
Collision time"
Factor from the acceleration in electric field
Abeco “International” Ltd. V1.2 2010
 
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In the presence of an electric field the
free electrons would have an
acceleration and its velocity would
steadily increase in proportion to the
field E
The electron is accelerated and then
makes collision with a lattice ion and
start accelerated again.
Part of the electron energy is
transferred to ion and turns into heat.
(vibrations of the ion = Phonons)
Abeco “International” Ltd. V1.2 2010
Collision with ions
a
c
c
e
l
e
r
a
ti
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n
Time
t Collision time
The average distance
between collisions is called
the Mean Free Path
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Each collision causes the loss of
energy sources needs to provide
adequate amount of energy to the
Load
the longer mean free path is, it is
less energy loss.
Collision with ions
a
c
c
e
l
e
r
a
ti
o
n
Time
t Collision time
Abeco “International” Ltd. V1.2 2010
• 
Average speed and energy of
charges (electrons) is constant
• 
For the transport of charges Q along
the electrical circuit, the electric field
E has to perform the work W.
• 
The same is the loss of charges Q
along the electrical circuit
• 
We need the Power P of the source
of electric field
Abeco “International” Ltd. V1.2 2010
∆P=i2*(R+R1+R2)= 69.12W
+
V
R1
54W
R = 10 Ohm
∆P=I2R =54W
R2
-
R1 and R2 =1 Ohm
R1=R2=0 Ohm
I=2.4 A
Electric potential
  Power
taken from the energy source to
perform of the same amount of work by
the resistor R = 54W or 69.12W
Abeco “International” Ltd. V1.2 2010
• 
Power of each electrical equipment is
determined by manufacturer at a given
voltage. Smaller losses greater voltage!
• 
All energy losses in the electrical circuit have
an impact on the efficient use of electricity.
Abeco “International” Ltd. V1.2 2010
Abeco “International” Ltd. V1.2 2010