| Brand | RW Energy | 
| Model NO. | High-Current Current-Limiting Circuit Breaker/Short-Circuit Current Limiter(FCL) | 
| Rated voltage | 20kV | 
| Rated normal current | 1250A | 
| Rated frequency | 50/60Hz | 
| Series | DDXK | 
A core protection component for high-capacity power systems (35kV-220kV grids, industrial parks), the FCL responds in ≤10ms to short-circuit faults. It limits peak fault current to 15%-50% of the expected value before safe breaking, shielding generators/transformers. Supporting 630A-4000A current ratings, it fits AC/DC systems and integrates with switchgear for stable grid operation.
Feature
High-Speed Interruption: It operates and interrupts the short-circuit current at the front part of the first power frequency half-cycle of the short-circuit current—well before the current rises to its peak. The total interruption time is 2–5 ms, approximately 10–20 times faster than that of conventional circuit breakers.
Current-Limiting Interruption: It starts limiting the short-circuit current 1 ms after a short-circuit occurs, and finally restricts the short-circuit current to 15%–45% of the expected value.
High Interruption Capacity: The rated prospective short-circuit interruption current ranges from 63 kA to 200 kA, while the rated short-circuit interruption current of currently common circuit breakers usually only reaches 40.5 kA to 50 kA.
Built-in Rogowski Current Sensor: It features accurate measurement, fast response speed, and can be arranged in a phase-separated manner or integrated into switchgear cabinets.
High Reliability: One of the product’s competitive advantages is its outstanding reliability. Special design and craftsmanship ensure the product’s high reliability, which has been verified and well-received in on-site applications.
Main Parameters
No.  |  
   Item  |  
   Unit  |  
   Technical Parameters  |  
  |
1  |  
   Rated Current  |  
   A  |  
   630~6300  |  
  |
2  |  
   Rated Voltage  |  
   kV  |  
   7.2/12/20/40.5  |  
  |
3  |  
   Rated Frequency  |  
   Hz  |  
   50/60  |  
  |
4  |  
   Rated Prospective Short - Circuit Breaking Current  |  
   kA  |  
   63/80/120  |  
  |
5  |  
   Rated Insulation Level (Power Frequency / Lightning)  |  
   7.2kV  |  
   kV  |  
   23/60 kV  |  
  
12kV  |  
   42/75 kV  |  
  |||
20kV  |  
   50/125 kV  |  
  |||
40.5kV  |  
   95/185 kV  |  
  |||
6  |  
   Breaking Time  |  
   ms  |  
   2~5ms  |  
  |
7  |  
   Cut - off Current / Prospective Short - Circuit Current Peak Value  |  
   %  |  
   20~45  |  
  |
8  |  
   DC Resistance of Main Circuit  |  
   μΩ  |  
   <40  |  
  |
9  |  
   Operating Current Setting Range  |  
   kA  |  
   6kA~60kA  |  
  |
10  |  
   Rated Breaking Current of Fuse  |  
   kA  |  
   63/120  |  
  |
11  |  
   Rated Short - time Withstand Current of Main Circuit  |  
   kA/s  |  
   31.5/2  |  
  |
12  |  
   Rated Peak Withstand Current of Main Circuit  |  
   kA  |  
   80  |  
  |

Figure 4: Using DDXK1 as rapid short-circuit protection for generators and transformers
(a) Rapid short-circuit protection at the 10kV/35kV side outlet of transformers
(b) Rapid short-circuit protection at generator outlets
(c) Rapid short-circuit protection for power plant branch busbars
(d) Rapid short-circuit protection at grid-connected generator outlets