The Generator Circuit Breaker designed for three-phases AC up to 15kV rated voltage, and can be used for switching and protecting generators in industrial, mining and power plants applications. The product conforms to IEC/IEEE 62271-37-013. The breaker can be installed in the switchgear in fixed or withdrawable arrangements. It is the optimum choice for the control and protection of MV generators.
Generator circuits exhibit unique challenges:
- High continuous current levels
- Significant DC component in fault current
- High asymmetry in the first cycle
- High rate-of-rise of recovery voltage (RRRV)
- Out-of-phase switching
DC Component dan Asymmetric Fault Current:
- In generator fault conditions, fault current contains a significant DC offset which can extend the peak current well beyond symmetrical values.
- Asymmetry can exceed 2.5x nominal current.
- Breaker must withstand and interrupt such conditions within 1–3 cycles.GCB must be tested for “full asymmetrical interruption”, as per IEEE C37.013.
Rate-of-Rise Recovery Voltage (RRRV) :
- Generator systems typically have very fast RRRV, especially during switching and fault clearing.
- GCB must resist dielectric failure after contact separation.
- Vacuum interrupters (such as the Eaton VCP-WG) are an ideal choice because of their fast dielectric recovery.
Switching Duty
| Duty Type | Requirement (IEEE C37.013) |
|---|---|
| Full asymmetrical | Yes |
| Out-of-phase switching | Up to 30° (6.5 pu voltage peak) |
| High current transfer | 12,000 A or more |
| TRV capability | 2–4 kV/µs |
The generator circuit breakers meet the strict service-duty requirements set forth by IEEE for generator Circuit applications, including:
- Generator circuit configuration
- High continuous current levels
- Unique fault current conditions
- Unique voltage conditions
- Very fast RRRV
- Out-of-phase switching
TECHNICAL DATA
| Parameter | Unit | 50 kA | 63 kA | 75 kA | |||
|---|---|---|---|---|---|---|---|
| DO | FIX | DO | FIX | DO | FIX | ||
| General | |||||||
| Maximum Voltage | kV | 15 | |||||
| Continuous Current | |||||||
| Rated Current | A rms | 1200 | 1200 | 1200 | 1200 | 1200 | 1200 |
| 2000 | 2000 | 2000 | 2000 | 2000 | 2000 | ||
| 3000 | 3000 | 3000 | 3000 | 3000 | 3000 | ||
| 4000 | 4000 | 4000 | 4000 | 4000 | 4000 | ||
| 5000 | 5000 | 5000 | 5000 | 5000 | 5000 | ||
| – | – | 6000 | 6000 | 6000 | 6000 | ||
| – | – | 6300 | 6300 | 6300 | 6300 | ||
| – | – | 7000 | 7000 | 7000 | 7000 | ||
| Dielectric Strength | |||||||
| Power Frequency Withstand Voltage | kV rms | 36 | |||||
| Lightning Impulse Withstand Voltage | kV peak | 95 | |||||
| Operating Time | |||||||
| Interrupting Time | ms | 50 | 50 | 83 | 83 | 83 | 83 |
| Closing Time | ms | 47 | |||||
| Minimum Opening Time | ms | 30 | 30 | 54 | 54 | 54 | 54 |
| Short Circuit Capability | |||||||
| Short Circuit Current | kA rms | 50 | 50 | 63 | 63 | 75 | 75 |
| Asymmetrical Interrupting Capability | % DC | 75 | 75 | 75 | 75 | 63 | 63 |
| Short-Time Current Carrying Capability | kA rms | 50 | 50 | 63 | 63 | 75 | 75 |
| Duration of Short-Time Current | s | 3 | 3 | 1.4 | 1.4 | 1 | 1 |
| Closing & Latching Capability | kA peak | 137 | 137 | 173 | 173 | 206 | 206 |
| Generator Source Interruption | |||||||
| 1st Symmetrical Current | kA rms | 25 | 25 | 31.5 | 31.5 | 40 | 40 |
| 1st Asymmetrical Current | % DC | 130 | |||||
| 2nd Symmetrical Current | kA rms | – | – | 40 | 40 | 50 | 50 |
| 2nd Asymmetrical Current | % DC | – | – | 110 | 110 | 110 | 110 |
| Transient Recovery Voltage (TRV) | |||||||
| RRRV | kV/µs | 3.4 | |||||
| TRV Peak (E2 = 1.84 × V) | kV peak | 27.6 | 30.9 | ||||
| Time to Peak (T2 = 0.62 × V) | µs | 9.3 | |||||
| Endurance | |||||||
| Load Switching Endurance | Operations | 10,000 | |||||
| No-load Mechanical Endurance | Operations | 10,000 | |||||