Energy Losses in the Electrical Circuits

Energy Losses in the Electrical Circuits

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 None of us expected such a large loss of energy in our companies

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

Current dependent - heat losses: on the Resistance (R) on the Harmonic Distortion on the Power Quality on Reactive Power

Losses in AC electrical circuits are dependent on the sum of all currents and resistance occurring in the circuit.

These losses are a function of the length of the electron mean free path in the metal - wire. injection Point defect Dislocation mean free path length depends on the number of electron collisions with: 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 Obcy atom Phonons

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. 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 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. 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. with Power Optimizer Metal structure with Power Optimizer Metal structure w/o Power Optimizer

Lower probability of collisions - less loss of energy, Less energy loss - less heat, Less heat - lower temperature, Lower temperature - lattice vibration smaller Smaller lattice vibration - lower probability of collisions Less energy loss - less energy bill

Each harmonics current flowing through the resistance causes heat-losses. As the harmonic frequency increases, resistance increases - the skin effect. Harmonic distortion - current [A] 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

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 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

Inductive load - draws current has two components Real current I supplies Real Power P [W] to the load - to perform work. - loss Pr=I 2 R Reactive current Ir supplies Reactive Power Q[var] to the load - energize the magnetic field of load (i.e.. motor) - loss Pre=Ir 2 R=(Q/U) 2 R Both currents supply Apparent Power S [VA] to the load - loss P= Pr+ Pre 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 "

In addition to reducing energy losses we would increase the efficiency of conversion of electricity to other energies. mechanical Heat light

Is regular three-dimensional lattice of ions containing a large number of electrons that are free to flow throughout the whole metal.

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 random move of the electrons

The electric field causes the electrons move opposite to the direction of the field E Flow of the electrons = electrical current 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

Average speed of electric charges constituting the current = 1A in the copper wire with cross section = 1mm 2 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 * 10 23 /mol, in 1 mm 3 =1.7*10 20 el/mm 3 charge in 1 mm 3 = 1.7*10 20 *1.6*10-19 =27 C/mm 3 Average speed of charge - 1A = 1C/s then 1/27 mm/s

T Charge density " Collision time" Factor from the acceleration in electric field

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) a c c e l e r a ti o n Collision with ions t Collision time Time The average distance between collisions is called the Mean Free Path

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. a c c e l e r a ti o n Collision with ions Time t Collision time

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

P=i2*(R+R1+R2)= 69.12W P=I 2 R =54W V R1 54W R2 + - R = 10 Ohm I=2.4 A R1 and R2 =1 Ohm R1=R2=0 Ohm Electric potential Power taken from the energy source to perform of the same amount of work by the resistor R = 54W or 69.12W

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.