접촉기,회로 차단기,태양광 인버터,전기 계량기,태양 전지
Coordination Standard: IEC 60947-2
핵심원리: The short-time delay protection time of the upper-level air circuit breaker (3WT) > the instantaneous trip time of the lower-level molded case circuit breaker, realizing precise isolation of faulty branches and avoiding system over-tripping.
| 응용 시나리오 | Parameters of Upper-level 기중 차단기 (3WT2M40 ETU35WT F-4P) | Selection and Parameters of Lower-level Molded Case Circuit Breaker (Siemens 3VL Series) | Coordination Effectiveness Judgment |
| High-power Motor Circuit | Overload long-time delay: Ir = 1600A (1.0×에서) | 모델: 3VL2740-1AA33-0AA0 | Lower-level instantaneous trip current (3200에이) < Upper-level short-time delay current (12800에이) |
| (예를 들어, 160kW/380V motor, rated current ≈ 320A) | Short-circuit short-time delay: Isd = 8×Ir = 12800A | 정격전류: 400에이 | Lower-level instantaneous operating time (≤ 0.02초) < Upper-level short-time delay time (0.2에스) |
| Short-time delay time: 0.2에스 | Overload long-time delay: Ir = 320A | ✓ Full selective coordination | |
| Instantaneous protection: 끄다 (Ii = Off) | Instantaneous trip: Ii = 10×Ir = 3200A | ||
| 여행 유형: TMD | |||
| General Power Circuit | Overload long-time delay: Ir = 1600A | 모델: 3VL2763-1AA33-0AA0 | Lower-level instantaneous current (4800에이) < Upper-level short-time delay current (9600에이) |
| (예를 들어, 물 펌프, 팬, total current ≈ 600A) | Short-circuit short-time delay: Isd = 6×Ir = 9600A | 정격전류: 630에이 | Lower-level operating time < Upper-level short-time delay time |
| Short-time delay time: 0.3에스 | Overload long-time delay: Ir = 600A | ✓ Full selective coordination | |
| Instantaneous protection: 끄다 | Instantaneous trip: Ii = 8×Ir = 4800A | ||
| 여행 유형: TMD | |||
| Lighting/Socket Distribution Circuit | Overload long-time delay: Ir = 1600A | 모델: 3VL2732-1AA33-0AA0 | Lower-level instantaneous current (3000에이) < Upper-level short-time delay current (8000에이) |
| (3상 4선식 시스템, total current ≈ 250A) | Short-circuit short-time delay: Isd = 5×Ir = 8000A | 정격전류: 320에이 | Operating time meets level difference |
| Short-time delay time: 0.2에스 | Overload long-time delay: Ir = 250A | ✓ Full selective coordination | |
| Instantaneous protection: 끄다 | Instantaneous trip: Ii = 12×Ir = 3000A | ||
| 여행 유형: TMD | |||
| Emergency Power Supply Circuit | Overload long-time delay: Ir = 1600A | 모델: 3VL2750-1AA33-0AA0 | Lower-level instantaneous current < Upper-level short-time delay current |
| (예를 들어, EPS/UPS output, current ≈ 400A) | Short-circuit short-time delay: Isd = 7×Ir = 11200A | 정격전류: 500에이 | Upper-level instantaneous current (16000에이) is much larger than that of the lower level; upper-level operates only in case of severe short circuit |
| Short-time delay time: 0.4에스 | Overload long-time delay: Ir = 400A | ✓ Selective coordination + backup protection | |
| Instantaneous protection: Ii = 10×In = 16000A | Instantaneous trip: Ii = 10×Ir = 4000A | ||
| 여행 유형: TMD |
Notes on Coordination Design
- Setting of Upper-level Instantaneous Protection: For branch short-circuit faults, it is recommended to turn off the instantaneous protection of 3WT (Ii = Off) and retain only the short-time delay protection; the instantaneous protection shall be enabled as backup only when bus short circuit occurs in the system (short-circuit current ≥ 12800A).
- Cable Cross-section Matching: The cable between the upper and lower-level circuit breakers shall meet the “short-circuit withstand capacity” to prevent cable burnout before the circuit breaker operates.
- Ambient Temperature Correction: When the temperature inside the distribution cabinet exceeds 40℃, derating of the rated current of the circuit breaker is required (derating by 1% for every 1℃ rise) to ensure stable protection characteristics.
- Selection of Lower-level Trip Type: TMD 트립 유닛 (열 자기 여행) is preferred for motor circuits, and MIC trip unit (전자 여행) can be selected for lighting circuits to improve protection accuracy.
