전력품질정의

전력품질의미

전력품질규정

영향적 파형

전력 품질평가

IEEE 1159규정

TypicalDuration

Typical SpectralContent

Nanosecond 5 ㎱ rise < 50 ㎱

Microsecond 1 ㎲ rise 50 ns - 1 ㎱millisecond 0.1 ㎱ rise > 1 ㎱Low Frequency < 5 ㎐ 0.3 - 50 ㎳ 0% ~ 400%Medium Frequency 5 - 500 ㎐ 20 ㎲ 0% ~ 800%High Frequency 0.5 - 5 ㎐ 5 ㎲ 0% ~ 400%Sag 0.5 - 30 cycle 10% ~ 90%Swell 0.5 - 30 cycle 110% ~ 180%Interruption 0.5 cycle - 3 s < 10%Sag 0.5 cycle - 3 s 10% ~ 90%Swell 0.5 cycle - 3 s 110% ~ 140%Interruption 3 s - 1 min < 10%Sag 3 s - 1 min 10% ~ 90%Swell 3 s - 1 min 100% ~ 120%

> 1 minute > 1 minute 80% ~ 90% > 1 minute 110% ~ 120% steady state 1% ~ 2% steady state 0% ~ .1%

0~100kHz steady state 0% ~ 20%0~6Hz steady state 0% ~ 2%Broad Band steady state < 25 ㎐ steady state 0% ~ 1%

intermittent 0% ~ 7% < 10 s

0%

Typical VoltageMagnitude

Power Frequency Variations

NotchingNoise

Waveform distortion

Voltage Fluctuations

Voltage ImbalanceDC Offset

HarmonicsInter - harmonics

Short -duration Variation

Interruption SustainedUnder voltagesOver voltages

Instantaneous

Momentary

Temporary

Short -duration Variation

Categories

Impulsive

Oscillatory

Transient

Safe Region

Transient

Swell

Overvoltage

Sag Low Voltage

DangerRegion 106%

87%

150K50~60 1250 1M 100M30M

Hz

Harmonicsradioactive

Noiseconductible

Noise

Surge

%

400

300

200

100

1µs 1ms 3ms 20ms 0.5s 10s Steady state

-2

-2

-1

-1

0

1

1

2

2

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0 1 2 3 4 5 6t [msec]

sin(x)0.8*sin(3*x+3.6)0.5*sin(5*x+0.6)

0.22*sin(7*x+3.8)

6펄스 12펄스 6펄스 12펄스

2nd – – 1.0% 1.0%

3rd – – 1.0% 1.0%

4th – – 1.0% 1.0%

5th 20.0% – 20.0% 2.0%

7th 14.3% – 12.0% 1.2%

11th 9.1% 9.1% 8.0% 8.0%

13th 7.7% 7.7% 7.0% 7.0%

17th 5.9% – 4.5% 0.5%

19th 5.3% – 4.0% 0.4%

23rd 4.3% 4.3% 3.0% 3.0%

25th 4.0% 4.0% 3.0% 3.0%

Harmonics이론적인 값 측정값

0.120.130.160.170.230.270.420.5966kV

0.240.260.320.350.460.550.861.233kV

0.360.390.470.530.690.821.31.822kV

0.70.760.911.31.62.53.56.6kV

23th초과23th19th17th13th11th7th5th전압

0.0110.8810.898Min

0.7290.9280.956Ave

0.9980.9790.999Max

역률

24[%]36[%]30[%]변압기 평균부하율

-10.14.9-4.3Min

-1.513.57.6Ave

14.820.218.5Max

무효[Mvar]

-1.522.217.2Min

20.633.728.8Ave

61.640.241.2Max

유효[MW]

6.623.317.7Min

24.136.430.2Ave

62.544.445.3Max

피상[MVA]

전력

1.7000.6001.850Min

5.1251.4424.529Ave

15.5603.27012.020Max

THD[%]

0.5461.3541.243평균 불평형율[%]

17584293Min

639961810Ave

252515212597Max

전류[A]

0.8400.9200.760Min

2.1691.6701.193Ave

4.1002.8002.120Max

THD[%]

0.1320.5650.136평균 불평형율[%]

20.43620.55820.192Min

21.79121.73721.722Ave

22.68222.58422.658Max

전압[V]

#3 Main Tr#2 Main Tr#1 Main Tr진단대상

전력품질Power Quality

20%이상

RST

Hz3th 5th 7th 9th 11th

각주파수영역별 크기가설정치이상인지점검

각상간의 실효치차가설정범위(예:20%) 이상여부 점검

반주기실효치와최대치의설정범위와의벗어남점검

고조파(전압/전류)전압/전류상간불평형고전압/저전압/순간정전

h

l

H

L

½ cycle

변압기기Transformer

RST

Coil 전원

차이나면결상

RST

Coil 전원

상이하면이상

RST

Coil 전원

크면기계적걸림

전류검출전불필요한아크현상발생여부점검

전류검출시간상호차이에서기계적걸림점검

검출전류시간비교, 결상점검

극간상태불균형기계적걸림순간결상

차단기기Circuit Breaker

출력으로나타나는결과치분석으로문제설비예지

맥류와직류로변화하는과정에서의문제설비예지

입력전원을분석하여Drive에미치는영향을예지

출력전원직류전원입력전원

AC

입력

Tr 52 LCONV

89

MDSLINV'HSC

B

드라이버Thy’or Driver

M

입측

출측10% 20%이상

RST

전류

설정값

각상간실효값의율(%)한계점검

변압기중성점접지의전류량이상한계점검

변압기입력, 출력측의전류비교허용범위점검

상간전류불평형접지전류검출입/출측전류(전압)비교