measure AC line
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Transcript of measure AC line
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5/21/2018 measure AC line
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C. Voltage )
AC . ,
. AC .
, , , , RMS .
RMS .
RMS .
. Current ) . .
.
. Frequence ) AC .
, 1 .
. Phase Angle and Power Factor ) AC .
(0~360 ) (0~2 ) .
, (volt) 0-360 2 .
.
0-360 2 .
.
( ) ( ) ,
( ) ( ) .
.
(degree) (phase angle).
.
AC , (cos) .
PF = cos 0 90 Radians .
. Watts and Vars ) (P) .
(P=EI).
X X (cos)
. (P=EIcos).
( )
2
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.
X ( ) .
0 ( ) cos 1 P=EI .
.
.
( ) .
.
, ?
. . Watthours) Varhours)
,
. ,
.
.
100 watt 1 100wh .
10,000vars(10Kvars) 24 240KVARHs
.
.
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AC
.
AC
. , , , , ,
.
AC
.
AC , , , AC
.
1. ?
* .
* .
* .
* .
2. ?
*
* PT CT
*
*
*
*
*
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Cccuracy ) : .
pparent Power ) : (Cos ) (VA) verage Value ) :
. , 0.637 .
alanced Load ) : 2 (1 3 , 3 3 , 3 4 ) AC .
Burden : . .
I x Z= VA I =
Z =
. .
E / Z= VA
E =
Z =
.
CT : AC . (Current Transfomer)CT Ratio : 2 1 .Error : ( ) .Frequence : 1 . (cycle/second)Harmonic :
.
Harmonic distortion : .
SCR Triac .
Hertz :High Voltage : 15KV 250KVHorse Power : 1HP = 746Watts .
.
Inductor : ( ) .
. , .
Killowatt : 1000Watt :WKillowatthour : 1 1000wattLagging Current : .
90 . , ,
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.
Leading Current : . 90 .
Low Voltage : 600voltMidium Voltage : 600volt 15kvOhm s Law : DC
V = I R, I = R/V
AC
Power Factor = COS = P/V x I
Z = V/I = P / I x C OS
I = V/Z = P/V x COS
V = IZ = P /I x C OS
P = I x Z x COS = V x I x COS Phase Angle : , . -
0 P.F = 1 .
-
90 P.F = 0 .
0 COS = 1, P=VI .
90 COS = 0, P=0 .
P = V x I x COS . COS power factor .
Power Factor P.F) : P.F AC cosin
VICOS P.F =
VI
P.F :
VICOS :
VI :
V :
I :
Primary : . ( 1 )
Reactive Power : . (VAR )VAR = V x I x SIN
R M S : Root mean square . . RMS ( ) watt .
DC .
RMS = 0.707 x
R T U : Remote Terminal Unit .
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. RTU SCADA SYSTEM .
SCADA : supervisory control and data aquisition.
.
Secondary : . ( 2 )
Sinusoidal Voltage and Current : : 0.707 x = RMS
: 0.637 x
True Power : . watt .WATT = V x I x COS
nbalanced Load ) : 2 (1 3 , 3 3 , 3 4 )
.
V.A : Volt Ampare . volt ampare .
VAR : VA . wattWATT : 1 1
1A 1 .
watt . "W"
Watthour : 1 watt 1 . "WH" .
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C .
.
: ,
, .
AC .
AC .
. .
2 .
(220)volts .
, (220)VAC 110V .
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. 220VAC ,
1/2 . 180 .
.
.
3HP 3 3 .
(A B, B C, A C) 220VAC 440VAC .
(Y) .
AC .
. , 3
.
) : 380VAC (A-B, B-C, A-C) : 380/ 3 = 220VAC (A-N, B-N, C-N)
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) AC
AC .
.
) AC
AC AC .
Ohm's Law : = X (E=IR). ,
.
AC 10ohm 15ohm 110 Volt AC
.
E= IR
110 VAC = I ( 10 Ohm) + (15 Ohm)
110 VAC = I ( 25 Ohm)
110VAC= I
25Ohm
4.4 Amps = I 4.4 A .
:
E= IR
E= ( 4.4 Amps) (10 Ohm) = 44 Volts AC
E= ( 4.4 Amps) (15 Ohm) = 66 Volts AC
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Kirchoff's Voltage Law .
0 .
44 VAC + 66 VAC = 110 VAC ( )
110 VAC .
,
.
( ),
.
. 1 . 1 .
CT AC .
.
CT 2 0-1mA DC 4-20mA DC DC
.
DC , , AC
.
. .
( ) VA VA .
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: 10 : 1 : VAp = Ep x Ip = 1000 VA
Ep = 100 VAC VAs = VAp - = 1000 VA
Ip = 10Amps AC Es = Ep / 10 = 10 VAC
= 0 Is = VAs / 10 = 100 Amps
2 2 .
CT :
2 VA .
. : 0.1 Ohm ( )
VA in = 50000 VA ( 100 V, 500 A ) : 1
E = IR, E = 5 Amps x 0.1 Ohm = 0.5 Volts : 2
CT CT , 0
.
CT CT 2
.
100 VAC x CT
500100 VAC x
5
100 VAC x 100 = 10,000 Volts
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CT (arc)
CT , ,
CT 2 .
.
.
:
Motor
) .
(PT) .
DC
(0 1 mA DC 4~12~20 mA DC) .
. 60Hz 5Hz 1 mA DC
60Hz 0 mA DC . 55 Hz -1 mA DC , 65 Hz
+1 mA DC .
4~20 mA DC . 60Hz 12 mADC
(12 mADC 4 mA DC 20 mA DC ) ,
55 Hz 4 mA DC 65 Hz 20 mA DC
) Watt Transducer ) " " . .
.
1 watt 1ohm 1volt 1 amp 1 volt .
AC
P= V x I x .
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,
.
fullscale
.
. 85-150 VAC 0-5
Amp . 0
150 VAC x 5 Amps x 1 = 750 watts .
, 110VAC 150volts
CT .
, (per element)
full scale 500watts .
. (single element) fullscale 500 watts , .
output range x 0.616 = 308 watts
* 0~1 mA DC
1 mA DC x 0.616 = 0.616 mA DC
* 4~20 mA DC16 mA DC x 0.616 = 9.856 mA DC + 4 mA DC = 13.856 mA DC .
( 0 )
uti-Element Transducer fullscale2 Element Transduce
2 3 3 .
Measured watts 308= = 0.616
fullscale watts 500
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2 2 . 1 500watts
1000 watts .
3 : P = 3EIcos .
, 2
. fullscale 1000watts 951watts
3 Element Transducer
3 3 4 . .
.
full scale 1500 watts . 1666, 2000, 4000watts
.
) . ;
VAR = V x I x sin .
30 (Lagging) .
P= VI x cos (cos ) ,
, .
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watts .
.
.
1, 2 3 . ,
PT's CT's .
.
. motor
0.6 (Lagging)
.
.
.
. , .
, . ,
.
.
, .
) .
.
, 1000 KWH/day .
.
? (
) .
15 . 15
X KWH , Y .
,
.
,
.
, (
) . (Load shedding) .
.
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.
.
( ) ( )
.
) . 1 VARH 1 VAR 0.1
10 VAR
15
.
,
.
, .
.
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C
.
AC
AC .
AC
. , , AC-DC
.
AC . , .
.
.
, .
,
.
.
,
.
, 1
.
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,
.
.
.
90 , 0 .
90 0
.
.
, .
,
.
.
.
.
.
, .
.
, .
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11 .
.
.
,
2% .
50 70 Hz .
AC
.
.
.
5 volt ,
.
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.
?
1. .
2. .
3. .
4. 50 70 Hz
1% 3% .
5. AC 6 7
.