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# Chapter 11 : AC Power Analysis - PowerPoint Presentation, Engineering Notes | EduRev

## : Chapter 11 : AC Power Analysis - PowerPoint Presentation, Engineering Notes | EduRev

``` Page 1

‹#› EENG 224
Chapter 11
AC Power Analysis
Huseyin Bilgekul
Eeng224 Circuit Theory II
Department of Electrical and Electronic Engineering
Eastern Mediterranean University
Chapter Objectives:
? Know the difference between instantaneous power and average
power
? Learn the AC version of maximum power transfer theorem
? Learn about the concepts of effective or Rms value
? Learn about the complex power, apparent power and power factor
? Understand the principle of conservation of AC power
? Learn about power factor correction

Page 2

‹#› EENG 224
Chapter 11
AC Power Analysis
Huseyin Bilgekul
Eeng224 Circuit Theory II
Department of Electrical and Electronic Engineering
Eastern Mediterranean University
Chapter Objectives:
? Know the difference between instantaneous power and average
power
? Learn the AC version of maximum power transfer theorem
? Learn about the concepts of effective or Rms value
? Learn about the complex power, apparent power and power factor
? Understand the principle of conservation of AC power
? Learn about power factor correction

‹#› EENG 224
An Electical Power Distribution Center
Page 3

‹#› EENG 224
Chapter 11
AC Power Analysis
Huseyin Bilgekul
Eeng224 Circuit Theory II
Department of Electrical and Electronic Engineering
Eastern Mediterranean University
Chapter Objectives:
? Know the difference between instantaneous power and average
power
? Learn the AC version of maximum power transfer theorem
? Learn about the concepts of effective or Rms value
? Learn about the complex power, apparent power and power factor
? Understand the principle of conservation of AC power
? Learn about power factor correction

‹#› EENG 224
An Electical Power Distribution Center
‹#› EENG 224
Apparent Power and Power Factor
1
2
cos( ) cos( )
m m v i Rms Rms v i
P V I V I ?? ?? = -= -
1
2
m m Rms Rms
S V I V I = =
Apparent Power
cos
Power Factor
()
v i
P
pf
Sp
S
Pf
??
= ×=
-
×
= =
? The Apparent Power is the product of the Rms value of voltage and current. It is
measured in V olt amperes (VA).
? The Power Factor (pf) is the cosine of the phase difference between voltage and
current. It is also the cosine of the angle of load impedance. The power factor may
also be regarded as the ratio of the real power dissipated to the apparent power of
? The Average Power depends on the Rms value of voltage and current and the
phase angle between them.
Page 4

‹#› EENG 224
Chapter 11
AC Power Analysis
Huseyin Bilgekul
Eeng224 Circuit Theory II
Department of Electrical and Electronic Engineering
Eastern Mediterranean University
Chapter Objectives:
? Know the difference between instantaneous power and average
power
? Learn the AC version of maximum power transfer theorem
? Learn about the concepts of effective or Rms value
? Learn about the complex power, apparent power and power factor
? Understand the principle of conservation of AC power
? Learn about power factor correction

‹#› EENG 224
An Electical Power Distribution Center
‹#› EENG 224
Apparent Power and Power Factor
1
2
cos( ) cos( )
m m v i Rms Rms v i
P V I V I ?? ?? = -= -
1
2
m m Rms Rms
S V I V I = =
Apparent Power
cos
Power Factor
()
v i
P
pf
Sp
S
Pf
??
= ×=
-
×
= =
? The Apparent Power is the product of the Rms value of voltage and current. It is
measured in V olt amperes (VA).
? The Power Factor (pf) is the cosine of the phase difference between voltage and
current. It is also the cosine of the angle of load impedance. The power factor may
also be regarded as the ratio of the real power dissipated to the apparent power of
? The Average Power depends on the Rms value of voltage and current and the
phase angle between them.
‹#› EENG 224
Apparent Power and Power Factor
? Not all the apparent power is consumed if the circuit is partly reactive.
Purely resistive
?
v
– ?
i
= 0,   Pf = 1
P/S = 1, all power are
consumed
Purely reactive
?
v
– ?
i
= ±90
o
,
pf = 0
P = 0, no real power
consumption
Resistive and
(R and L/C)
?
v
– ?
i
> 0
?
v
– ?
i
< 0
P/S < 1, Part of the apparent
power is consumed
Page 5

‹#› EENG 224
Chapter 11
AC Power Analysis
Huseyin Bilgekul
Eeng224 Circuit Theory II
Department of Electrical and Electronic Engineering
Eastern Mediterranean University
Chapter Objectives:
? Know the difference between instantaneous power and average
power
? Learn the AC version of maximum power transfer theorem
? Learn about the concepts of effective or Rms value
? Learn about the complex power, apparent power and power factor
? Understand the principle of conservation of AC power
? Learn about power factor correction

‹#› EENG 224
An Electical Power Distribution Center
‹#› EENG 224
Apparent Power and Power Factor
1
2
cos( ) cos( )
m m v i Rms Rms v i
P V I V I ?? ?? = -= -
1
2
m m Rms Rms
S V I V I = =
Apparent Power
cos
Power Factor
()
v i
P
pf
Sp
S
Pf
??
= ×=
-
×
= =
? The Apparent Power is the product of the Rms value of voltage and current. It is
measured in V olt amperes (VA).
? The Power Factor (pf) is the cosine of the phase difference between voltage and
current. It is also the cosine of the angle of load impedance. The power factor may
also be regarded as the ratio of the real power dissipated to the apparent power of
? The Average Power depends on the Rms value of voltage and current and the
phase angle between them.
‹#› EENG 224
Apparent Power and Power Factor
? Not all the apparent power is consumed if the circuit is partly reactive.
Purely resistive
?
v
– ?
i
= 0,   Pf = 1
P/S = 1, all power are
consumed
Purely reactive
?
v
– ?
i
= ±90
o
,
pf = 0
P = 0, no real power
consumption
Resistive and
(R and L/C)
?
v
– ?
i
> 0
?
v
– ?
i
< 0