POWER SYSTEM OVERVIEW AND SUMMARY

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POWER SYSTEMS: AN INTRODUCTION OR OVERVIEW WITH A FOCUS ON TRANSMISSION LINE PARAMETERS : 

POWER SYSTEMS: AN INTRODUCTION OR OVERVIEW WITH A FOCUS ON TRANSMISSION LINE PARAMETERS ENGR. LIZETTE IVY G. CATADMAN REGISTERED ELECTRICAL ENGINEER MASTER OF ENGINEERING, MAJOR IN ELECTRICAL ENGINEERING PROFESSIONAL TEACHER

FOUR PRINCIPAL DIVISIONS OF ELECTRIC POWER SYSTEMS : 

FOUR PRINCIPAL DIVISIONS OF ELECTRIC POWER SYSTEMS

GENERATING STATIONS : 

GENERATING STATIONS INSTALLATIONS OR PLANTS WHERE ELECTRIC POWER IS PRODUCED (GENERATED) FROM VARIED SOURCES. GENERATION (ELECTRICITY) THE PROCESS OF PRODUCING ELECTRICAL ENERGY FROM OTHER FORMS OF ENERGY.

GENERATORS : 

GENERATORS THE THREE-PHASE (AC) SYNCHRONOUS GENERATOR OR ALTERNATOR ONE OF THE MOST ESSENTIAL COMPONENTS OF THE POWER SYSTEM.  IT HAS TWO SYNCHRONOUSLY ROTATING FIELDS: FIELD PRODUCED BY THE ROTOR DRIVEN AT SYNCHRONOUS SPEED AND EXCITED BY DC CURRENT. FIELD PRODUCED BY THE STATOR WINDINGS BY THE THREE-PHASE ARMATURE CURRENTS.

GENERATORS : 

GENERATORS THE GENERATOR EXCITATION SYSTEM MAINTAINS GENERATOR VOLTAGE AND CONTROLS THE REACTIVE POWER FLOW. THEY LACK THE COMMUTATOR; AC GENERATORS CAN GENERATE HIGH POWER AT HIGH VOLTAGE, TYPICALLY 30 KV. IN A POWER PLANT, THE SIZE OF THE GENERATORS CAN VARY FROM 50 MW TO 1500 MW.

GENERATION SYSTEM : 

GENERATION SYSTEM THE SOURCE OF MECHANICAL POWER IS THE PRIME MOVER. HYDRAULIC TURBINES AT WATERFALLS STEAM TURBINES WHOSE ENERGY COMES FROM THE BURNING COAL, GAS, AND NUCLEAR FUEL GAS TURBINES INTERNAL COMBUSTION ENGINES THAT BURNS OIL

GENERATION SYSTEM : 

GENERATION SYSTEM STEAM TURBINES OPERATE AT RELATIVELY HIGH SPEEDS OF 1800 OR 3600 RPM. THE GENERATORS TO WHICH THEY ARE COUPLED HAVE CYLINDRICAL OR ROUND ROTORS. TWO-POLE FOR 3600 RPM FOUR-POLE FOR 1800 RPM

GENERATION SYSTEM : 

GENERATION SYSTEM CYLINDRICAL OR ROUND ROTORS HAS ONE DISTRIBUTED WINDING AND UNIFORM AIR GAP. RELATIVELY LARGE AXIAL LENGTH AND SMALL DIAMETER TO LIMIT THE CENTRIFUGAL FORCE. ACCOUNTS FOR ABOUT 70% OF THE LARGE SYNCHRONOUS GENERATORS BEING USED.

GENERATION SYSTEM : 

GENERATION SYSTEM HYDRAULIC TURBINES, PARTICULARLY THOSE OPERATING WITH A LOW PRESSURE, OPERATE AT LOW SPEED. THEIR GENERATORS ARE USUALLY SALIENT TYPE ROTORS WITH MANY POLES. SALIENT TYPE ROTOR CONCENTRATED WINDINGS ON THE POLES AND NONUNIFORM AIRGAPS. RELATIVELY LARGE NUMBER OF POLES, SHORT AXIAL LENGTH, AND LARGE DIAMETER. IN A POWER STATION, SEVERAL GENERATORS ARE OPERATED IN PARALLEL IN THE POWER GRID TO PROVIDE THE TOTAL POWER NEEDED. CONNECTED AT A COMMON POINT CALLED A BUS.

TRANSMISSION LINES : 

TRANSMISSION LINES CONSIST OF ALL THE CONNECTING LINKS BETWEEN THE GENERATING STATIONS AND THE DISTRIBUTION SYSTEMS. THE INTERCONNECTIONS OF SEVERAL POWER SYSTEMS CREATE THE GRIDS.

THE GRID : 

THE GRID TRANSMISSION GRID HIGH-VOLTAGE NETWORK FOR LONG-DISTANCE ELECTRIC POWER TRANSMISSION. DISTRIBUTION GRID MEDIUM- AND LOW-VOLTAGE NETWORK FOR LOCAL DISTRIBUTION OF ELECTRIC POWER TO END-USERS OR CONSUMERS.

THE GRID : 

THE GRID USUALLY THE GRID CONTAINS MANY SUBSTATIONS THAT ARE CONNECTED VIA TRANSMISSION LINES TO ONE ANOTHER. THESE SUBSTATIONS CONTAIN PROTECTIVE EQUIPMENTS THAT, IN CASE OF PROBLEMS AUTOMATICALLY OPERATE CIRCUIT BREAKERS, DISCONNECTING CERTAIN PORTIONS OF THE GRID FROM THE GRID.

THE BUS : 

THE BUS IN A SUBSTATION, EACH BUS HAS LARGE CIRCUIT BREAKERS CONNECTING: ONE OR MORE TRANSMISSION LINES ONE OR MORE TRANSFORMERS ONE OR MORE GENERATORS ONE OR MORE LOADS (DISTRIBUTION OF ELECTRIC ENERGY TO USERS) TO ONE OR MORE BUSES AT ONE OR MORE POINTS OF DIFFERENT VOLTAGES; IN RARE CASES, EVEN AT DIFFERENT FREQUENCIES.

TRANSFORMERS : 

TRANSFORMERS TRANSFORMERS TRANSFER POWER WITH VERY HIGH EFFICIENCY FROM ONE LEVEL OF VOLTAGE TO ANOTHER LEVEL. STEP-UP TRANSFORMERS ARE USED FOR TRANSMISSION OF POWER. AT THE RECEIVING END OF THE TRANSMISSION LINES, STEP-DOWN TRANSFORMERS ARE USED TO REDUCE THE VOLTAGE TO SUITABLE VALUES FOR DISTRIBUTION OR UTILIZATION.

TRANSMISSION AND SUBTRANSMISSION : 

TRANSMISSION AND SUBTRANSMISSION THE PURPOSE OF AN OVERHEAD TRANSMISSION NETWORK TRANSFER ELECTRIC ENERGY FROM GENERATING UNITS AT VARIOUS LOCATIONS TO THE DISTRIBUTION SYSTEM, WHICH ULTIMATELY SUPPLIES THE LOAD.

TRANSMISSION AND SUBTRANSMISSION : 

TRANSMISSION AND SUBTRANSMISSION TRANSMISSION LINES ALSO INTERCONNECT NEIGHBORING UTILITIES THAT PERMIT NOT ONLY ECONOMIC DISPATCH OF POWER WITHIN REGIONS DURING NORMAL CONDITIONS, BUT ALSO THE TRANSFER OF POWER BETWEEN REGIONS DURING EMERGENCIES.

TRANSMISSION AND SUBTRANSMISSION : 

TRANSMISSION AND SUBTRANSMISSION HIGH VOLTAGE TRANSMISSION LINES ARE TERMINATED AT SUBSTATIONS CALLED HIGH-VOLTAGE SUBSTATIONS, RECEIVING SUBSTATIONS, OR PRIMARY SUBSTATIONS. THE FUNCTION OF SOME SUBSTATIONS IS SWITCHING CIRCUITS IN AND OUT OF SERVICE CALLED SWITCHING STATIONS.

TRANSMISSION AND SUBTRANSMISSION : 

TRANSMISSION AND SUBTRANSMISSION AT PRIMARY SUBSTATIONS, THE VOLTAGE IS STEPPED-DOWN TO A VALUE MORE SUITABLE FOR THE NEXT PART OF THE JOURNEY TOWARDS THE LOAD. PORTION OF THE TRANSMISSION SYSTEM THAT CONNECTS THE HIGH-VOLTAGE SUBSTATIONS, THROUGH STEP-DOWN TRANSFORMERS, TO THE DISTRIBUTION SUBSTATIONS IS CALLED SUB-TRANSMISSION NETWORK.

TRANSMISSION LEVELS : 

TRANSMISSION LEVELS SHORT TRANSMISSION LINES UP TO 50 MILES LONG ( < 80 KM) MEDIUM (LENGTH) TRANSMISSION LINES 50 TO 150 MILES LONG (80 KM TO 240 KM) LONG TRANSMISSION LINES ABOVE 150 MILES ( > 240 KM)

COMMON TYPES OF CONDUCTORS USED IN OVERHEAD TRANSMISSION : 

COMMON TYPES OF CONDUCTORS USED IN OVERHEAD TRANSMISSION AAC - ALL-ALUMINUM CONDUCTOR AAAC - ALL-ALUMINUM ALLOY CONDUCTOR ACSR – ALUMINUM CONDUCTOR, STEEL REINFORCED ACAR – ALUMINUM CONDUCTOR, ALLOY REINFORCED

Slide 31: 

AAC - ALL-ALUMINUM CONDUCTOR AAAC - ALL-ALUMINUM ALLOY CONDUCTOR

Slide 32: 

ACSR - ALUMINUM CONDUCTOR, STEEL REINFORCED ACAR – ALUMINUM CONDUCTOR, ALLOY REINFORCED

FOR UNIFORM DIAMETER STRAND LEVELS & CORRESPONDING NUMBER OF CONDUCTORS PER LEVEL : 

FOR UNIFORM DIAMETER STRAND LEVELS & CORRESPONDING NUMBER OF CONDUCTORS PER LEVEL NOTE:THIS IS ONLY FOR CABLES WITH CONDUCTORS OF UNIFORM DIAMETER.

DISTRIBUTION SYSTEM : 

DISTRIBUTION SYSTEM CONNECTS ALL INDIVIDUAL LOADS TO THE TRANSMISSION LINES AT SUBSTATIONS WHICH PERFORM VOLTAGE TRANSFORMATION AND SWITCHING FUNCTIONS. TO MINIMIZE THE SIZE OF THE CONDUCTORS USED FOR THE TRANSMISSION. TO LESSEN THE VOLTAGE DROP OF THE LINE.

VOLTAGE LEVEL CLASSIFICATION : 

VOLTAGE LEVEL CLASSIFICATION

LOADS : 

LOADS LOADS OF POWER SYSTEMS ARE DIVIDED INTO: INDUSTRIAL LARGE INDUSTRIAL LOADS ARE SERVED FROM THE SUB-TRANSMISSION NETWORK. SMALL INDUSTRIAL LOADS ARE SERVED FROM THE PRIMARY DISTRIBUTION NETWORK. COMMERCIAL RESIDENTIAL

LOADS : 

LOADS INDUSTRIAL LOADS ARE COMPOSITE LOADS INDUCTION MOTORS FORM A HIGH PORTION OF THESE LOAD. COMMERCIAL AND RESIDENTIAL LOADS CONSIST LARGELY OF SMALL APPLIANCE, LIGHTING, HEATING, AND COOLING. THE MAGNITUDE OF LOAD VARIES THROUGHOUT THE DAY, AND POWER MUST BE AVAILABLE TO CONSUMERS ON DEMAND.

LOADS : 

LOADS DAILY LOAD CURVE OF A UTILITY COMPANY COMPOSITE OF DEMANDS MADE BY VARIOUS CLASSES OF USERS. THE GREATEST VALUE OF LOAD DURING A 24-HOUR PERIOD IS CALLED THE PEAK OR MAXIMUM DEMAND. SMALLER PEAKING GENERATORS MAY BE COMMISSIONED TO MEET THE PEAK LOAD FOR ONLY A FEW HOURS.

SYSTEM PROTECTION : 

SYSTEM PROTECTION IN ADDITION TO GENERATORS, TRANSFORMERS, AND TRANSMISSION LINES, OTHER DEVICES ARE REQUIRED FOR THE SATISFACTORY OPERATION AND PROTECTION OF A POWER SYSTEM. THE PROTECTIVE DEVICES DIRECTLY CONNECTED TO THE CIRCUITS ARE CALLED SWITCHGEARS.

SYSTEM PROTECTION : 

SYSTEM PROTECTION INCLUDES INSTRUMENT TRANSFORMERS, CIRCUIT BREAKERS, DISCONNECT SWITCHES, FUSES, AND LIGHTNING ARRESTERS. THE ASSOCIATED CONTROL EQUIPMENTS AND PROTECTIVE RELAYS ARE PLACED ON SWITCHBOARDS IN CONTROL HOUSES.

SYSTEM PROTECTION : 

SYSTEM PROTECTION CIRCUIT BREAKERS CAN BE OPERATED FROM THE MAIN SWITCHING CONSOLE, OR THEY CAN BE OPERATED AUTOMATICALLY FROM A PROTECTION RELAY OR SOME OTHER PROTECTION DEVICE. ENSURES THAT IN CASE OF A LOCAL OVERLOAD THE CIRCUIT BREAKER/S CONCERNED WILL OPEN IMMEDIATELY.

SYSTEM PROTECTION : 

SYSTEM PROTECTION DISCONNECTING THE CIRCUIT AND STOPPING THE CURRENT, WHICH IS HIGHER THAN A GIVEN LIMIT, FROM DOING ANY DAMAGE, EVEN FROM STARTING ANY FIRES. IF THE PROTECTIVE DEVICE DISCOVERS THAT THE PROBLEM IS OUTSIDE THE LOCAL AREA, THEN A TIME DELAY IS ACTIVATED TO PERMIT THE PROBLEM AREA TO DO ITS SWITCHING FIRST.

SYSTEM PROTECTION : 

SYSTEM PROTECTION AFTER THE SET TIME DELAY, THE RELEVANT CIRCUIT BREAKER, AS A BACKUP, WILL BE OPERATED TO SWITCH THE LINE OFF IF THE PROBLEM STILL CONTINUES. OTHER PROTECTIVE DEVICES MAY BE ACTIVATED AUTOMATICALLY IF THE VOLTAGE IS NOT WITHIN A GIVEN SET RANGE, OR "LOAD SHEDDING" COULD BE ACTIVATED IN CASE OF A LOCAL OVERLOAD.

SYSTEM PROTECTION : 

SYSTEM PROTECTION “LOAD SHEDDING” WILL SWITCH OFF A PREDETERMINED PORTION OF THE DISTRIBUTION SYSTEM, WHILE LEAVING ON ONLY HOSPITALS, SECURITY AREAS, AND OTHER HIGH-PRIORITY LOADS. A "RECLOSING FEATURE" IS USUALLY ALSO A PART OF THE POWER SYSTEM AUTOMATION.

SYSTEM PROTECTION : 

SYSTEM PROTECTION RECLOSING FEATURE AN IMPORTANT FEATURE TO DEAL WITH VERY SHORT LOCAL PROBLEMS LIGHTNING STRIKES TREE BRANCHES OTHER WEATHER-RELATED PROBLEMS AN ANIMAL CAUSING A TEMPORARY SHORT CIRCUIT.

SYSTEM PROTECTION : 

SYSTEM PROTECTION A RECLOSING OF ONE OR MORE CIRCUIT BREAKERS MAY BE ACTIVATED IMMEDIATELY AFTER A DISCONNECTION HAS OCCURRED. BUT ONLY ONCE, AND OFTEN AT THAT TIME EVERYTHING IS BACK TO NORMAL IF NOT, THEN A SECOND, PERMANENT, DISCONNECTION IS ACTIVATED. SOME SUBSTATIONS ALSO INCLUDE A SYNCHRONIZER TO ENSURE AUTOMATIC SYNCHRONIZATION BEFORE TWO CIRCUITS CAN BE CONNECTED TOGETHER.

SYSTEM PROTECTION : 

SYSTEM PROTECTION BEFORE GENERATORS CAN BE CONNECTED TO A BUS THAT IS CONNECTED TO THE GRID ,THE SYNCHRONIZER ENSURES THE PROPER PHASE AND VOLTAGE RELATION BETWEEN THE TWO CIRCUITS TO BE CONNECTED TOGETHER. TAKES A SHORT TIME FOR A CIRCUIT BREAKER TO ACTUALLY EFFECT THE CONNECTION. THE TIME DELAY MUST BE TAKEN INTO CONSIDERATION BY THE SYNCHRONIZER.

SYSTEM PROTECTION : 

SYSTEM PROTECTION THE SPEED OF A GENERATOR IS RELATED TO THE FREQUENCY OF ITS OUTPUT, AND THAT SPEED IS CHANGED AS REQUIRED BY THE SYNCHRONIZER TO ENSURE BOTH SIDES OF THE CIRCUIT BREAKER ARE AT VERY NEARLY THE SAME FREQUENCY, WITHIN SET LIMITS, BEFORE THE "CONNECT" SIGNAL IS SENT BY THE SYNCHRONIZER TO THE CIRCUIT BREAKER.

PARAMETERS OF TRANSMISSION LINES : 

PARAMETERS OF TRANSMISSION LINES RESISTANCE, R – OHM, O INDUCTANCE, L – HENRY, H CAPACITANCE, C – FARAD, F CONDUCTANCE, G – SIEMENS, UNIT IS SYMBOLIZED BY “MHO” OR THE INVERTED O ADMITTANCE, Y – SIEMENS, “MHO” OR INVERTED O

RESISTANCE : 

RESISTANCE THE OPPOSITION TO THE FLOW OF CURRENT IN A CONDUCTOR. THE MOST IMPORTANT CAUSE OF POWER LOSS IN A TRANSMISSION LINE. THE AMOUNT OF RESISTANCE IN A CONDUCTOR IS DIRECTLY PROPORTIONAL TO THE LENGTH OF THE CONDUCTOR AND INVERSELY PROPORTIONAL TO THE CROSS-SECTIONAL AREA OF THE CONDUCTOR.

RESISTANCE (DC) : 

RESISTANCE (DC) WHERE: R = RESISTANCE IN OHMS ? = RESISTIVITY OF THE CONDUCTOR L = LENGTH OF THE CONDUCTOR A = CROSS-SECTIONAL AREA OF THE CONDUCTOR

RESISTIVITIES OF COMMON ELEMENTS AND ALLOYS@ 20OC, cirmil-ohm/ft : 

RESISTIVITIES OF COMMON ELEMENTS AND ALLOYS@ 20OC, cirmil-ohm/ft ACSR : 17.62 OHM-CIRMIL/FT

RESISTIVITIES OF COMMON ELEMENTS AND ALLOY@ 20oC, x 10–8 ohm-m : 

RESISTIVITIES OF COMMON ELEMENTS AND ALLOY@ 20oC, x 10–8 ohm-m

RESISTANCE : 

RESISTANCE CONVERSION FACTOR 1 INCH = 1000 MILS

EFFECT OF TEMPERATURE TO THE RESISTANCE OF THE CONDUCTOR : 

EFFECT OF TEMPERATURE TO THE RESISTANCE OF THE CONDUCTOR WHERE: T = INFERRED ABSOLUTE TEMPERATURE (THE ABSOLUTE VALUE OF THE TEMPERATURE AT WHICH THE RESISTANCE OF A MATERIAL IS ZERO.)

INFERRED ABSOLUTE TEMPERATURES FOR METALS @ oC : 

INFERRED ABSOLUTE TEMPERATURES FOR METALS @ oC

EFFECT OF TEMPERATURE TO THE RESISTANCE OF THE CONDUCTOR : 

WHERE: = TEMPERATURE COEFFICIENT OF RESISTANCE EFFECT OF TEMPERATURE TO THE RESISTANCE OF THE CONDUCTOR

COEFFICIENT OF RESISTANCE OF ELEMENTS AND ALLOYS AT /oC : 

COEFFICIENT OF RESISTANCE OF ELEMENTS AND ALLOYS AT /oC

RESISTANCE (AC) : 

RESISTANCE (AC) AFFECTED BY: FREQUENCY SPIRALING TEMPERATURE WHEN AC FLOWS IN A CONDUCTOR, CURRENT DISTRIBUTION IS NOT UNIFORM OVER THE CONDUCTOR CROSS-SECTIONAL AREA; SKIN EFFECT. CURRENT DENSITY IS GREATEST AT THE SURFACE OF THE CONDUCTOR. CAUSES AC RESISTANCE TO BE HIGHER THAN THE DC RESISTANCE.

RESISTANCE (AC) : 

RESISTANCE (AC) STRANDED CONDUCTORS ARE SPIRALED. EACH STRAND IS LONGER THAN THE FINISHED CONDUCTOR. RESULTS IN A SLIGHTLY HIGHER RESISTANCE THAN DC RESISTANCE. CONDUCTOR RESISTANCE INCREASES AS TEMPERATURE INCREASES. CONTRIBUTES TO STRETCHING OF THE CONDUCTORS. CONDUCTOR RESISTANCE IS BEST DETERMINED FROM MANUFACTURER’S DATA SHEETS.

INDUCTANCE : 

INDUCTANCE THE PROPERTY OF AN ELECTRIC CIRCUIT BY WHICH A CHANGING MAGNETIC FIELD CREATES AN ELECTROMOTIVE FORCE, OR VOLTAGE, IN THAT CIRCUIT OR IN A NEARBY CIRCUIT. THE PROPERTY OF AN ELECTRIC CIRCUIT THAT OPPOSES ANY CHANGE IN THE CURRENT.

INDUCTANCE : 

INDUCTANCE SINGLE-PHASE, TWO-WIRE LINE WHERE: D = DISTANCE BETWEEN THE TWO WIRES WHERE: r = RADIUS OF THE CONDUCTOR

INDUCTANCE : 

INDUCTANCE SINGLE-PHASE, TWO-WIRE LINE COMPOSITE CONDUCTORS WHERE: GMD = GEOMETRIC MEAN DISTANCE = DM, MUTUAL DISTANCE GMR = GEOMETRIC MEAN RADIUS = DS, SURFACE/SELF DISTANCE

INDUCTANCE : 

INDUCTANCE THREE-PHASE LINE WITH EQUILATERAL SPACING WHERE: D = EQUILATERAL DISTANCE

INDUCTANCE : 

INDUCTANCE THREE-PHASE LINE WITH UNSYMMETRICAL SPACING

BUNDLED CONDUCTORS : 

BUNDLED CONDUCTORS AT EXTRA-HIGH VOLTAGES (EHV), CORONA WITH ITS RESULTANT POWER LOSS AND PARTICULARLY ITS INTERFERENCE WITH COMMUNICATIONS IS EXCESSIVE IF THE CIRCUIT HAS ONLY ONE CONDUCTOR PER PHASE. THE HIGH VOLTAGE GRADIENT AT THE CONDUCTOR IN THE EHV RANGE IS REDUCED CONSIDERABLY BY HAVING TWO OR MORE CONDUCTORS PER PHASE IN CLOSE PROXIMITY COMPARED WITH THE SPACING BETWEEN PHASES.

BUNDLED CONDUCTORS : 

BUNDLED CONDUCTORS THE BUNDLE CONSISTS OF TWO, THREE, OR FOUR CONDUCTORS. THREE-CONDUCTOR BUNDLE - THE CONDUCTORS AT THE VERTICES OF AN EQUILATERAL TRIANGLE FOUR-CONDUCTOR BUNDLE - THE CONDUCTORS AT THE CORNERS OF A SQUARE. REDUCED REACTANCE IS THE OTHER EQUALLY IMPORTANT ADVANTAGE OF BUNDLING. INCREASING THE NUMBER OF CONDUCTORS IN A BUNDLE REDUCES THE EFFECTS OF CORONA AND REDUCES THE REACTANCE. THE REDUCTION OF THE REACTANCE RESULTS FROM THE INCREASED GMR OF THE BUNDLE.

INDUCTANCE : 

INDUCTANCE BUNDLED CONDUCTORS

PARALLEL CIRCUIT OR DOUBLE CIRCUIT : 

PARALLEL CIRCUIT OR DOUBLE CIRCUIT TWO, THREE-PHASE CIRCUITS THAT ARE IDENTICAL IN CONSTRUCTION AND ELECTRICALLY IN PARALLEL HAVE THE SAME INDUCTIVE REACTANCE. THE INDUCTIVE REACTANCE OF THE SINGLE EQUIVALENT CIRCUIT, HOWEVER, IS HALF THAT OF EACH OF THE INDIVIDUAL CIRCUITS CONSIDERED ALONE ONLY IF THEY ARE SO WIDELY SEPARATED THAT THERE IS NEGLIGIBLE MUTUAL INDUCTANCE BETWEEN THEM.

PARALLEL CIRCUIT OR DOUBLE CIRCUIT : 

PARALLEL CIRCUIT OR DOUBLE CIRCUIT IF THE TWO CIRCUITS ARE ON THE SAME TOWER, THE METHOD OF GMD IS USED TO FIND THE INDUCTANCE PER PHASE BY CONSIDERING ALL THE CONDUCTORS OF ANY PARTICULAR PHASE TO BE STRANDS OF ONE COMPOSITE CONDUCTOR.

INDUCTANCE : 

INDUCTANCE PARALLEL OR DOUBLE-CIRCUIT

INDUCTIVE REACTANCE : 

INDUCTIVE REACTANCE

INDUCTIVE REACTANCE : 

INDUCTIVE REACTANCE

INDUCTIVE REACTANCE : 

INDUCTIVE REACTANCE

CAPACITANCE : 

CAPACITANCE AREA OF THE PLATES LARGER PLATES PROVIDE GREATER CAPACITY TO STORE ELECTRIC CHARGE. THEREFORE, AS THE AREA OF THE PLATES INCREASE, CAPACITANCE INCREASES. DISTANCE BETWEEN THE PLATES IT IS DIRECTLY PROPORTIONAL TO THE ELECTROSTATIC FORCE FIELD BETWEEN THE PLATES. THIS FIELD IS STRONGER WHEN THE PLATES ARE CLOSER TOGETHER. THEREFORE, AS THE DISTANCE BETWEEN THE PLATES DECREASES, CAPACITANCE INCREASES. ABILITY OF THE DIELECTRIC TO SUPPORT ELECTROSTATIC FORCES.

CAPACITANCE : 

CAPACITANCE CAPACITANCE EXISTS BETWEEN THE TRANSMISSION LINE WIRES. THE TWO OR THREE WIRES ACT AS PLATES OF THE CAPACITOR AND THE AIR BETWEEN THEM ACTS AS A DIELECTRIC. THIS ELECTRIC FIELD BETWEEN THE WIRES IS SIMILAR TO THE FIELD THAT EXISTS BETWEEN THE PLATES OF A CAPACITOR.

CAPACITANCE : 

SINGLE-PHASE, TWO-WIRE LINE CAPACITANCE

CAPACITANCE : 

CAPACITANCE THREE-PHASE LINE WITH EQUILATERAL SPACING WHERE: D = EQUILATERAL DISTANCE

CAPACITANCE : 

CAPACITANCE THREE-PHASE LINE WITH UNSYMMETRICAL SPACING WHERE:

CAPACITANCE : 

CAPACITANCE BUNDLED CONDUCTORS

CAPACITANCE : 

CAPACITANCE PARALLEL OR DOUBLE-CIRCUIT

CAPACITANCE WITH EFFECT OF GROUND : 

CAPACITANCE WITH EFFECT OF GROUND EARTH AFFECTS THE CAPACITANCE OF A TRANSMISSION LINE ITS PRESENCE ALTERS THE ELECTRIC FIELD OF THE LINE. ASSUMED THAT THE EARTH IS A PERFECT CONDUCTOR IN THE FORM OF A HORIZONTAL PLANE OF INFINITE EXTENT THE ELECTRIC FIELD OF CHARGED CONDUCTORS ABOVE THE EARTH IS NOT THE SAME AS IT WOULD IF THE EQUIPOTENTIAL SURFACE OF THE EARTH WERE NOT PRESENT. THE ELECTRIC FIELD OF THE CHARGED CONDUCTORS IS FORCED TO CONFORM TO THE PRESENCE OF THE EARTH’S SURFACE.

CAPACITANCE WITH EFFECT OF GROUND : 

CAPACITANCE WITH EFFECT OF GROUND FOR PURPOSE OF CALCULATING THE CAPACITANCE: THE EARTH IS REPLACED BY A FICTITIOUS CHARGED CONDUCTOR BELOW THE SURFACE OF THE EARTH BY A DISTANCE EQUAL TO THAT OF THE OVERHEAD CONDUCTOR ABOVE THE EARTH. SUCH A CONDUCTOR HAS A CHARGE EQUAL IN MAGNITUDE AND OPPOSITE IN SIGN TO THAT OF THE ORIGINAL CONDUCTOR AND IS CALLED THE IMAGE CONDUCTOR.

CAPACITANCE : 

CAPACITANCE WITH EFFECT OF GROUND

CAPACITIVE REACTANCE : 

CAPACITIVE REACTANCE

CAPACITIVE REACTANCE : 

CAPACITIVE REACTANCE

CAPACITIVE REACTANCE : 

CAPACITIVE REACTANCE

SHORT TRANSMISSION LINE : 

SHORT TRANSMISSION LINE

MEDIUM (LENGTH) TRANSMISSION LINE : 

MEDIUM (LENGTH) TRANSMISSION LINE ABCD CONSTANTS NOMINAL ? NOMINAL T

MEDIUM (LENGTH) TRANSMISSION LINE : 

MEDIUM (LENGTH) TRANSMISSION LINE NOMINAL ?

MEDIUM (LENGTH) TRANSMISSION LINE : 

MEDIUM (LENGTH) TRANSMISSION LINE NOMINAL T

LONG TRANSMISSION LINE : 

LONG TRANSMISSION LINE ABCD CONSTANTS ABCD CONSTANTS

LONG TRANSMISSION LINE : 

LONG TRANSMISSION LINE PLEASE SHIFT CALCULATOR MODE TO RADIANS.

EXAMPLE : 

EXAMPLE A THREE-PHASE, 60 HZ TRANSMISSION LINE IS COMPOSED OF ACSR DRAKE CONDUCTORS EQUILATERALLY SPACED AT 12 FT BETWEEN CENTERS. THE LINE DELIVERS 55 MVA AT 0.8 PF LAGGING TO A BALANCED LOAD AT 132 KV. DETERMINE THE SENDING END VOLTAGE AND CURRENT. ASSUME A WIRE TEMPERATURE OF 50oC. IF IT WERE 40 MILES LONG IF IT WERE 80 MILES LONG IF IT WERE 160 MILES LONG