2 Power Quality Voltage Variation Transient Wave Shape

2. Power Quality의 평가요소는? ● Voltage Variation(전압변동), Transient 전압, Wave Shape(파형특성), Voltage Imbalance(불균형전압), Flicker ● 전기 System 설계 Error ● 전기 System 시공 Error ● Grounding Error ● 고조파(K-Factor, Crest-Factor, TDD, THD) ● 부하의 상호간섭

6. Voltage Variation(전압변동)이란? 발생원인: 전력사고(단락, 지락등), 차단기 동작에 의한 Backlash, 부하의 급격한 변화, Weak Net(나약한 전력망). ITIC Curve : Voltage Tolerance Envelope Transient 500 Swell 400 300 200 과 전압 Safe Region Danger Region (위험한 영역) Safe Region (안전한 영역) 106 % 100 87 % 저 전압 Sag 0 1µs 1 ms 3 ms 20 ms 0. 5 s 10 s Steady State

EX) Sag 파 형 Example: 2 Phase Sag and 50% of nominal Example: 10%of nominal

EX) Converter-Load 파형

EX) Converter-Load (정현파)

EX) Converter-Load (정현파 + 3고조파)

EX) Converter-Load (정현파 + 3고조파 + 5고조파) Synthesis of a wave form

EX)Converter-load(정현파 + 3고조파 + 5고조파 + 7고조파 Synthesis of a wave form

EX) Converter-Load (합성 결과 파형)

EX) Converter-Load (고조파 찻수 분석)

Detuning Factor (fn= 60 Hz) 공진차수 공진주파수 Detuning Factor 5. 0 300 Hz 4% 4. 2 252 Hz 5. 67% 4. 08 245 Hz 6% 3. 78 227 Hz 7% 2. 67 161 Hz 14%

16. Power Quality 요약 P. Q. Monitoring Power Quality Solution §Real Time rms전압, 역률, • Power factor Correction §Voltage regulations Gas type Capacitor §ITIC(CBEMA) Plot Tuned & de-tuned filter §Sag, transient Automatic PFC • Voltage Disterbance §고조파 §에너지 Demand Surge Protection(TVSS) §Data 수집, 분석 Sag Correction EVR • Harmonic Solution K-factor transformer Noise cut transformer P. Q. Consulting § Site survey §현장부하 조사 §문제해결 §에너지 과소비 대책 Power Quality Problem Active-filter Third harmonic filter Tuned & De-tuned filter • 무정전 Static transfer Switch UPS