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ERRA Tailor-made Educational Workshop: Power System Basics for Non-EngineersJanuary 26-28, 2020 | Muscat, Oman
Terminology and Basics
Barış Sanlıbarissanli.com
ERRA Tailor-made Workshop for Authority for Electricity Regulation, Oman (AER):
Power System Basics for Non-Engineers
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History
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Resources
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Why history?
● Knowing historical context and pathways ● History does not repeat itself, but it rhymes
(Mark Twain)● Markets can be made but not happen
overnight● Regulation changes when technology
changes
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Leyden Jar
● Lawyer Andreas Cuneus, 1746● Filling a jar with water and electrifying it by touching a wire sitting in
the water with an electrified glass vial● Electricity generated by electrostatic machines charged metal foil
and water
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Louis XV
● For amusement● 180 gendarmes in a big circle in Grande Gallerie● Holding next man’s hand● Surprised by the shock● King and his men found the leaping gendarmes both marvelous and
hilarious
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Benjamin Franklin
● 1744 saw in Boston, Electrified Boy experiment
● 1747 wrote “I never before was engaged in any study”
● To a friend in London “If there is no other use discovered of electricity, this however is considerable, that it may make a vain man humble.”
● Hundreds of experiments
● 1749, “A turkey is to be killed for our dinner by the electrical shock, and roasted by the electrical jack, before a fire kindled by the electrified bottle; when the health of all the famous electricians in England, Holland, France, and Germany are to be drank [sic] in electrified bumpers, under the discharge of guns from the electrical battery.”
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Lightning● Franklin suspected lightning was simply a massive jolt of electricity
● 1750, proposed tall pointed metal poles to conduct the lightning down to ground
● Lightning could be collected into Leyden jars
● While trying to kill a turkey with electricity shocked himself: a universal blow throughout my whole body from head to foot
● 1752, kite experiment
– the loose threads of the hempen string rising as if electrified – Once the string was wet, the electricity from the passing lightning
storm flowed steadily down it
Benjamin Franklin
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Experiment with Lightning
● 1752, May 10 French stored lightning in jar
● 1753, Georg Richman, a Swedish scientist in St Petersburg tried to replicate, electrocuted
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Galvani and Volta
● Luigi Galvani, University of Bologna, physician and anatomist● Alessandro Volta, University of Pavia, prof of physics● Galvani -> role of electricity in the workings of the body’s nerves and
muscles● Volta-> looking at the basic nature of electricity and its chemical
reactions
Galvani
Galvani
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Galvani and the frog
● 26 Jan 1781, Galvani while dissecting a large frog’s leg. Nearby an electrostatic machine turned on.
● When touched leg jerked● “I immediately repeated the experiment. I touched the other end of
the crural nerve with the point of my scalpel, while my assistant drew sparks from the electrical machine. At each moment when sparks occurred the muscle was seized with convulsions.”
● “animal electricity”● Published papers 1791, “On the Effect of Electricity on the Motion of
the Muscles.”
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Volta
● Already inducted into Royal Society, son of a nobleman● Condensing electroscope that measured charge● First applauded “fine and grand discovery of animal electricity”● 1794, he was convinced electricity was actuall metallic.... “animal
versus metallic electricity”
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Napoleon
● 1796 Napoleon Bonaparte ● Luigi Galvani refused to oath to new government● Expelled in April 1798 from Unversity, died in December penniless● Volta, accepted and contiued as professor
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Volta continued experimenting
● Tested dissimilar metals and measured charges with his electroscope
● Effect was stronger when he touched the metals, “effect of saline moisture”
● 1800, March 20, wrote a letter to president of Royal Society “no apology... electricity excited by the mere mutual contact of different kinds of metals”
● Copper and zinc disks seperated by pasteboard soaked with salt water
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Battery
● Letter reached Royal Society 26 June 1800● Battery is declared : “the most wonderful apparatus that has ever
come from the hand of man, not excluding even the telescope or the steam engine.”
● Volta’s electrical pile● Steady current of electricity is known as Galvani
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Humphry Davy
● Chemist● October 1807, demonstrated compounds could be decomposed into
thei basic elements by electricity● Alkalies -> potash and soda ash... entirely new elements potassium
and sodium● Later more new elements
– Magnesium, calcium, barium, strontium
Humphry Davy – Battery, 1809
Oersted● 1820 Spring, Hans Christian Oersted, physics prof at the Uni of
Copenhagen during a lecture● A small Voltaic Battery● Intended to heating platinum wire by electricity● Wildly swinging magnetic needle● He moved wire around and needle responded strongly as if to a magnet● Strived to establish relationship between magnetism and electricity● Needle right angle to charged wire
Oersted
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Electromagnetism
● 21 July 1820, Oersted announced “electromagnetism” in a four page paper in latin
● Experiments on the effect of an electric current on the magnetic needle”
● Parisian prof of math Andre Marie Ampere read the experiment and was sceptical
● Replicated experiment
– Strength of the magnetic field intensified with the rise of the electric current
● More powerful electromagnets
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Faraday
● Education ended at age 12. Apprenticed for 7 years to a bookbinder● A customer gave him the tickets to Humphry’s highly popular series
“The elements of Chemical Philosophy”● He took extensive notes, compiled an index, bound it together into a
book● Wrote to Humphry● Impressed by 22 year old Faraday, hired as assistant
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Faraday
● 1822 wrote to lab book “Convert magnetism into electricity”● 1824 became a Fellow of the Royal Society● At 33, appointed director of the Royal Ins. Lab.● 29 August 1831
– Only on/off generated charge
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Electricity by magnets
● Electric current is set up in a closed circuit by changing magnetic field
● 24 Nov 1831, world’s first electric dynamo as “A new electrical machine” to Royal Society
● Resolved long debate electricity produced by lightning, electrostatics, batteries, and generator are the same invisible entity.
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First applications
● Improving batteries● 1840, a workable telegraph● But gas was popular, 1875 there were more than 400 gas lighting
companies in US● Arc lighting : “One could in fact have believed that the sun had risen.
This illusion was so strong that birds, woken out of their sleep, began singing in the artificial daylight.”
● Battery 20 times more expensive than supplied by steam engines
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Generator and motor
● Early 1870s Belgian engineer Zenobe-Theophile Gramme designed a powerful direct current generator also an electric motor
● Advance of Werner von Siemens.. used electromagnet instead of regular magnets
● With dynamo, 1876 Russian military engineer Paul Jablochkoff came with a Jablochkoff candle
– More gentle, carbon sticks seperated by kaolin cement, runs for 16 hours
● 1878 half mile of avenue de l’Opera – arc lighting
DC/AC
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Enter the Edison
● Edison’s long time friend Prof George Barker● Tried but no effect of interest in Edison● First dynamo designed by Americans, Farmer and Wallace● Barker escorted Edison to Wallace’s brass foundry● 8 horsepower electric dynamo, “telemachon”● Edison : “I believe I can beat you making the electric light. I do not
think you are working in the right direction.”
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Electric car
● Scottish Robert Anderson, 1834-1835 first electric transportation● 1842 no charging● 1865 French Gaston Plante lead-acid battery● 1879 First gas engine Carl Benz● 1914 Ford
September 16, 1878, New York Sun, EDISON’S NEWEST MARVEL. SENDING CHEAP LIGHT, HEAR, AND POWER BY ELECTRICITY”
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Edison’s Network
Part 2Terminology & Basics
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Resources
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Electricity
● Energy carrier
– Not an energy source, but proxy● What is moving?
– Pulse... not electrons● Behaves like light
– Can you store light? Why not?
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Ways to generate electricity
● Electron in balance
– Excess- deficit● Static● Chemical (historical)● Mechanic (contemporary)● Physics – semi conductor/ quantum
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Magnetism
● Generation
● Transformer
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Physics of Electricity
● Benjamin Franklin late 1700s
– Charge -> “positive” or “negative”● Electric current -> the ability of electrons to travel● Charges spread out
– A local accumulation or deficit of electrons causes a “discomfort” or “tension”
– Discomfort level is potential-tension ● A charge move to a more “comfortable” location by producing heat in
wire
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Potential
● There has to be a “reference” location -> ground● Potential represents a measure of how comfortable or
uncomfortable it would be for any charge to reside at that location● One volt -> One joule/coulomb● The wire is “12kV” means wire to ground
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Conductivity
● Imagine electrons moving a little to side like people, giving its neighbor a repulsive “shoulder” in metrobus
● Metals are important● But air can ionize -> plasma (salt, wet air)● Superconduction
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Current
● Current is the flow rate of charge● If
– Voltage is a measure of “how badly the stuff wants to get there”– Current is a measure of “how much stuff is actually going”
● Amperes “amps”, I ,flow rate of charge● General sense “positive” flow is current● What is travelling is “pulse” or “signal” of current
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Ohm’s Law
● V = IR● Resistance
– Matter properties * length / cross-section– Resistance of copper wire increases as it heats up
● Higher flow (current) higher friction (heat & loss)
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Other● Electric circuit
– Pathway to recycle charge to “less comfortable” position
– Closed /open circuit● Voltage Drop
– Current and resistance determines voltage drop● Electric Shock
– Current that causes biological damage
– “keep one hand in pocket”● Resistive heating
– Result of “friction”... undesireable in transmission
– Thermal expansion & sagging
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Resistive heating
● P = I * V● V= I*R
● P = I* I* R = I 2*R
● Resistive heating -> square of current● More sensitive to current changes● For a required P, choose I and V
– Either increase cross-section or decrease length– Edison system limited to be only a few miles
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Field● Electric/Magnetic Field
– Like gravity● Electric Field (+/-)
– Affects charge, radial● Magnetism (N-S)
– Divide magnet till atoms, still N-S● 1820 Oersted observed compass needle moved by current through a nearby wire
● Magnetic field must be changing in order to have any effect
● Force exerted on charge is EMF
● Electromagnetic force acts on electrons-> accelerate
● “Induced current” induced by changing magnetic field
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Kirchhoff’s Law
● German physicist Gustav Robert Kirchhoff● KVL
● KCL
● Ex : LED strip has 50 LED’s plugged to 240 V
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Magnetic Circuits
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DC and AC
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AC Power
● AC frequency 50 Herts -> 50 times/second● Main reason is it allows
– Raising and lowering the voltage by means of transformers– In DC it is more expensive– But safety of high voltage AC
● Transformers introduced in 1880s,● DC – AC battle, by mid 1890s resolved
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Early frequency
● Different across 25 Hz to 133 1/3 cycles ● For generators
– Lower freq -> fewer magnetic poles● For transmission
– Lower freq->line’s resistance(!) increases with f● For loads
– Higher freq-> less flickering
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Modern electricity system
● Edison DC-110 Volt● Tesla 240 V – 60 hertz● Westinghouse arc lights 60 hertz● Germany AEG, 50 Hertz, 120 V● Europe 120 V till 1950s then 220 V● UK converted to both 220 V and 50 hertz
https://www.quora.com/Electrical-Engineering-Why-is-Indias-frequency-maintained-in-50-Hz-only
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Frequency
https://link.springer.com/article/10.1007/s40565-017-0315-y
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Math
● A sinusoidal function
– Amplitude, freq, phase– Freq: number of complete oscillations per unit time– Phase: Starting point of sinusoid
● RMS value
– DC equivalent of sinusoid
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Reactance (to freq)
● Reactance property fo a device to influence the relative timing of an alternating voltage and current
● Inductance- L- (voltage leads V=max, I = 0)
– Changing magnetic field induces an opposing current– Magnetic field increases and decreases during different parts of the cycle, it stores
and releases energy. Energy no dissipated but exchanged (between magnetic field and the rest of circuit)
● Capacitance- C- (current leads I max, V = 0)
– Current flow across a capacitor is proportional to rate of change of electric field
● Impedance Z= R +jX
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Power & Loads● Power is a measure of energy per unit time
● P= I2R, “dissipated”-> converted to heat
● Line drop : few % of line voltage
● Real power, active power, P (MW)
● Apparent power, S (kVA,MVA)
● Reactive power, Q (VAR)
● Power factor
– Desirable 0.8-0.9● Inductive loads consume reactive energy
● Capacitive loads supply reactive energy
● Most loads and lines -> inductive
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Load
https://seffaflik.epias.com.tr/transparency/tuketim/gerceklesen-tuketim/gercek-zamanli-tuketim.xhtml
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Power Factor
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3 types of loads
● Resistive
● Inductive
● Capacitive
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Reactive Power
● “The cholesterol of power lines”● With capacitors “VAR compensation”, near load● Planning and scheduling reactive power generat.● Fluorescent lamps
– Ballasts 0.6 electronic, 0.5 for magnetic
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Generator
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Electromagnet Generator
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Prime Movers - Coal
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Prime movers - Nuclear
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Prime Movers - Hydro
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PM – Pumped Storage
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PM - CCGT
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PM - Wind
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PM – Direct Solar
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Generators
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Solid State wave form
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System Overview
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Carrying electricity
● USB cables
– 2.0 max 5 meter– 3.0 max 3 meter
● Voltage drop across line
– Cable– Current
● Higher voltage less loss
https://goughlui.com/2014/10/01/usb-cable-resistance-why-your-phonetablet-might-be-charging-slow/
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Transmission Lines
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Conductor Types
● Solid●
● Stranded●
● Alu. Conductor, Steel Reinforced
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Conductor Size
● American Standard Wire Gauge (AWG)
– Reverse order● Number smaller -> conductor bigger
● Circular Mills (> AWG 4/0)
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Transmission Voltage
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Substations
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Substations● Transformers
● Regulators
● Circuit breakers and reclosers
● Air disconnect switches
● Lightning Arresters
● Electrical buses
● Capacitor banks
● Reactors
● Static VAR compensators
● Control building
● Preventative maintenance
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Transformers
Step down
Distribution
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Inside and connections
Transformer core and coils
Bushing
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PT and CT
● Potential Transformers
– Metering, protective relaying and sys monitoring
● Current Transformers
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Autotransformers
● Specially constructed variations of regular two winding transformers. They share a winding..
● Both windings on the common core● Works best with small turns (5:1)
– 500kV-230kV.... 345 kV to 120kV
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Regulators
● Steady-regulated voltage (Ex: 240 Vac regulated to +-5%)● First costumer should not exceed 252 V, last customer should not be less that
222 V)● Load tap changer
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Load tap changer
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Circuit breakers
● Oil (OCB) ● Gas (SF6 – sulfur hexafluoride) (GCB)● Vacuum● Air
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Breaks (Disconnect Switches)
● Vertical break● Horizontal break● Gang operated(3 phase)
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Electrical Bus
● Electrical bus connects equipment together
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Capacitor Banks
● Online continuously or turned on/off to meet dynamic reactive requirements
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Reactors
● Another name for a high voltage-inductor (one winding transformer)
– Absorbing surplus VAR (reactive power) or line charging: capacitance effect of long lines
– Connected in series to reduce fault current in distribution lines
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Static VAR Compensator (SVC)
● To control power flow, improve stability, reduce system losses● Several capacitors +inductors+electronic switching● When voltage low, SVC generates reactive power(capacitive)● When voltage high, SVC absorbs reactive power (inductive)
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Distribution Voltages
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Distribution feeders
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Three phase Distribution Transformers
One bushing transformer
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Metering
Electromechanical Solid state
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One line diagram
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Underfrequency Relays
● Load shed relays
– @ 49.8 Hz shed a minimum 10% of a load
– @ 49.5 Hz shed a minimum 10% of a load
– @ 49.2 Hz shed a minimum 10% of a load
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Zone or Distance Relays
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Load
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Load – First days of Ramadan
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Q3 – Electricity in heating
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How Turkey uses its energy
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Interconnected Grid
https://electronicsystematic.blogspot.com/2018/02/turkiye-enterkonnekte-sebeke-sistemi.html
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How system is balanced
● Voltage and frequency
– Voltage reactive→
– Frequency generation→● Day ahead planning● Reserve and security margins● Flexibility is important● Real time management
