BALANCE THREE PHASE SYSTEM DET 101 - Electric Circuit Fundamentals I CHAPTER 6 BALANCE THREE PHASE SYSTEM PPKSE
DET 101 - Electric Circuit Fundamentals I INTRODUCTION In general, three phase systems are preferred over single phase systems for the transmission of the power system for many reasons, including the following: Thinner conductors can be used to transmit the same kVA at the same voltage, which reduces the amount of copper required (typically about 25% less) and turn reduces construction and maintenance costs. PPKSE
DET 101 - Electric Circuit Fundamentals I INTRODUCTION The lighter lines are easier to install, and the supporting structures can be less massive and farther apart. Three phase equipment and motors have preferred running and starting characteristics compared to single phase systems because of a more even flow of power to the transducer than can be delivered with a single phase supply. PPKSE
DET 101 - Electric Circuit Fundamentals I INTRODUCTION In general, most larger motors are three phase because they are essentially self starting and do not require a special design or additional starting circuitry. PPKSE
DET 101 - Electric Circuit Fundamentals I THREE PHASE VOLTAGES The generator basically consists of a rotating magnet (called the rotor) surrounded by a stationary winding (called the stator). Three separate windings or coils with terminals a-a’, b-b’ and c-c’ are physically placed 120o apart around the stator. PPKSE
DET 101 - Electric Circuit Fundamentals I GENERATED VOLTAGES The three phase generator can supply power to both single phase and three phase loads PPKSE
DET 101 - Electric Circuit Fundamentals I THREE PHASE GENERATOR PPKSE
THREE PHASE GENERATOR Phase voltages of a three phase generator PPKSE DET 101 - Electric Circuit Fundamentals I THREE PHASE GENERATOR Phase voltages of a three phase generator PPKSE
DET 101 - Electric Circuit Fundamentals I THREE PHASE GENERATOR The sinusoidal expression for each of the phase voltages PPKSE
THREE PHASE GENERATOR The phasor diagram of the phase voltages PPKSE DET 101 - Electric Circuit Fundamentals I THREE PHASE GENERATOR The phasor diagram of the phase voltages PPKSE
THREE PHASE GENERATOR The effective value of each is determined by DET 101 - Electric Circuit Fundamentals I THREE PHASE GENERATOR The effective value of each is determined by PPKSE
DET 101 - Electric Circuit Fundamentals I THREE PHASE GENERATOR Rearranging the phasors and apply a law of vectors which states that the sum of any vectors drawn such that the head of one is connected to tail of the next, and that the head of the last vector is connected to the tail of the first is zero. PPKSE
Y CONNECTED GENERATOR IL = Line current DET 101 - Electric Circuit Fundamentals I Y CONNECTED GENERATOR IL = Line current IØg = Phase current of the generator The point at which all the terminals are connected is called the neutral point PPKSE
Y CONNECTED GENERATOR Relation between line and phase voltages DET 101 - Electric Circuit Fundamentals I Y CONNECTED GENERATOR Relation between line and phase voltages Appying Kirchhoff’s Law: PPKSE
DET 101 - Electric Circuit Fundamentals I Y CONNECTED GENERATOR PPKSE
Y CONNECTED GENERATOR From the phasor diagram that θ of EAB = ß = 300 DET 101 - Electric Circuit Fundamentals I Y CONNECTED GENERATOR From the phasor diagram that θ of EAB = ß = 300 PPKSE
Y CONNECTED GENERATOR In sinusoidal notation PPKSE DET 101 - Electric Circuit Fundamentals I Y CONNECTED GENERATOR In sinusoidal notation PPKSE
Y CONNECTED GENERATOR Phase voltage & Line voltage PPKSE DET 101 - Electric Circuit Fundamentals I Y CONNECTED GENERATOR Phase voltage & Line voltage PPKSE
Y CONNECTED GENERATOR Vector sum of the line voltages PPKSE DET 101 - Electric Circuit Fundamentals I Y CONNECTED GENERATOR Vector sum of the line voltages PPKSE
PHASE SEQUENCE (Y CONNECTED GENERATOR) DET 101 - Electric Circuit Fundamentals I PHASE SEQUENCE (Y CONNECTED GENERATOR) The phase sequence can be determined by the order in which the phasors representing the phase voltages pass through a fixed point on the phasor diagram if the phasors are rotated in a counterclockwise direction. PPKSE
PHASE SEQUENCE (Y CONNECTED GENERATOR) DET 101 - Electric Circuit Fundamentals I PHASE SEQUENCE (Y CONNECTED GENERATOR) Phase sequence from phase voltage Phase sequence is ABC This phase sequence can also be is BCA or CAB PPKSE
PHASE SEQUENCE (Y CONNECTED GENERATOR) DET 101 - Electric Circuit Fundamentals I PHASE SEQUENCE (Y CONNECTED GENERATOR) Phase sequence from phase voltage Phase sequence is ABC PPKSE
PHASE SEQUENCE (Y CONNECTED GENERATOR) DET 101 - Electric Circuit Fundamentals I PHASE SEQUENCE (Y CONNECTED GENERATOR) PPKSE
PHASE SEQUENCE (Y CONNECTED GENERATOR) DET 101 - Electric Circuit Fundamentals I PHASE SEQUENCE (Y CONNECTED GENERATOR) PPKSE
Y CONNECTED GENERATOR WITH Y CONNECTED LOAD DET 101 - Electric Circuit Fundamentals I Y CONNECTED GENERATOR WITH Y CONNECTED LOAD PPKSE
Y CONNECTED GENERATOR WITH Y CONNECTED LOAD DET 101 - Electric Circuit Fundamentals I Y CONNECTED GENERATOR WITH Y CONNECTED LOAD If the load is balanced, the neutral connection can be removed without affecting the circuit in any manner PPKSE
Y CONNECTED GENERATOR WITH Y CONNECTED LOAD DET 101 - Electric Circuit Fundamentals I Y CONNECTED GENERATOR WITH Y CONNECTED LOAD PPKSE
DET 101 - Electric Circuit Fundamentals I PPKSE
DET 101 - Electric Circuit Fundamentals I EXAMPLE The phase sequence of the Y-connected generator in figure below is ABC. Find the phase angles v2 and v3. Find the magnitude of the line voltages. Find the line currents. Verify that, since the load is balanced, IN 0. PPKSE
DET 101 - Electric Circuit Fundamentals I EXAMPLE PPKSE
DET 101 - Electric Circuit Fundamentals I SOLUTION PPKSE
DET 101 - Electric Circuit Fundamentals I SOLUTION PPKSE
DET 101 - Electric Circuit Fundamentals I SOLUTION PPKSE
DET 101 - Electric Circuit Fundamentals I SOLUTION PPKSE
DET 101 - Electric Circuit Fundamentals I WYE – DELTA SYSTEM PPKSE
DET 101 - Electric Circuit Fundamentals I WYE – DELTA SYSTEM PPKSE
DET 101 - Electric Circuit Fundamentals I WYE – DELTA SYSTEM PPKSE
EXAMPLE For the three-phase system of figure below: DET 101 - Electric Circuit Fundamentals I EXAMPLE For the three-phase system of figure below: Find the phase angles v2 and v3. Find the current in each phase of the load. Find the magnitude of the line currents. PPKSE
DET 101 - Electric Circuit Fundamentals I EXAMPLE PPKSE
DET 101 - Electric Circuit Fundamentals I SOLUTION PPKSE
DET 101 - Electric Circuit Fundamentals I SOLUTION PPKSE
DELTA CONNECTED GENERATOR DET 101 - Electric Circuit Fundamentals I DELTA CONNECTED GENERATOR PPKSE
DELTA CONNECTED GENERATOR DET 101 - Electric Circuit Fundamentals I DELTA CONNECTED GENERATOR PPKSE
DELTA CONNECTED GENERATOR DET 101 - Electric Circuit Fundamentals I DELTA CONNECTED GENERATOR At node A PPKSE
DELTA CONNECTED GENERATOR DET 101 - Electric Circuit Fundamentals I DELTA CONNECTED GENERATOR Phasor Diagram PPKSE
DELTA CONNECTED GENERATOR DET 101 - Electric Circuit Fundamentals I DELTA CONNECTED GENERATOR Using the same procedure to find the line current as was used to find the line voltage of a Y-connected generator produces the following: PPKSE
DELTA CONNECTED GENERATOR DET 101 - Electric Circuit Fundamentals I DELTA CONNECTED GENERATOR Phasor Diagram PPKSE
PHASE SEQUENCE (DELTA CONNECTED GENERATOR) DET 101 - Electric Circuit Fundamentals I PHASE SEQUENCE (DELTA CONNECTED GENERATOR) PPKSE
DELTA – DELTA & DELTA - WYE THREE PHASE SYSTEM DET 101 - Electric Circuit Fundamentals I DELTA – DELTA & DELTA - WYE THREE PHASE SYSTEM PPKSE
THREE PHASE POWER WYE CONNECTED LOAD Average Power (for each phase) DET 101 - Electric Circuit Fundamentals I THREE PHASE POWER WYE CONNECTED LOAD Average Power (for each phase) PPKSE
THREE PHASE POWER For balanced Load (Total power delivered) PPKSE DET 101 - Electric Circuit Fundamentals I THREE PHASE POWER For balanced Load (Total power delivered) PPKSE
THREE PHASE POWER Reactive Power (for each phase) DET 101 - Electric Circuit Fundamentals I THREE PHASE POWER Reactive Power (for each phase) (Total reactive power) PPKSE
THREE PHASE POWER Apparent Power (for each phase) PPKSE DET 101 - Electric Circuit Fundamentals I THREE PHASE POWER Apparent Power (for each phase) PPKSE
THREE PHASE POWER (Total Apparent power) PPKSE DET 101 - Electric Circuit Fundamentals I THREE PHASE POWER (Total Apparent power) PPKSE
THREE PHASE POWER Power factor of the system PPKSE DET 101 - Electric Circuit Fundamentals I THREE PHASE POWER Power factor of the system PPKSE
EXERCISE THREE PHASE POWER PPKSE DET 101 - Electric Circuit Fundamentals I THREE PHASE POWER EXERCISE PPKSE
THREE PHASE POWER DELTA CONNECTED LOAD PPKSE DET 101 - Electric Circuit Fundamentals I THREE PHASE POWER DELTA CONNECTED LOAD PPKSE
THREE PHASE POWER Average Power PPKSE DET 101 - Electric Circuit Fundamentals I THREE PHASE POWER Average Power PPKSE
THREE PHASE POWER Reactive Power PPKSE DET 101 - Electric Circuit Fundamentals I THREE PHASE POWER Reactive Power PPKSE
THREE PHASE POWER Apparent Power PPKSE DET 101 - Electric Circuit Fundamentals I THREE PHASE POWER Apparent Power PPKSE
THREE PHASE POWER Power Factor PPKSE DET 101 - Electric Circuit Fundamentals I THREE PHASE POWER Power Factor PPKSE
DET 101 - Electric Circuit Fundamentals I EXERCISE PPKSE