Fault current time 1, 3 or 5 sec

In summary, the conversation discusses how to determine the fault current time for grounding cable sizing and the related temperature to the selected timing. It also mentions the required cross section of the cable conductor, the constant factor, and the allowed temperature increase. Additionally, the conversation touches on how much reactive energy will be dumped during a short circuit event and the fusion current and heat capacity of the chosen conductor.
  • #1
Khaled Abuzaid
2
0
Any idea how can we decide on the fault current time 1, 3 or 5 sec. for grounding cable sizing? Also, what is the related temperature to the selected timing?
 
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  • #2
How much reactive energy are you going to be dumping from which parts of your system during an event (short circuit plus time to open a breaker)? What is the fusion current for the conductor chosen? What is the heat capacity of the conductor (how long at fusion current to melt)?
 
  • #3
Khaled Abuzaid said:
Any idea how can we decide on the fault current time 1, 3 or 5 sec. for grounding cable sizing? Also, what is the related temperature to the selected timing?
Required cross section of cable conductor in mm2 is :
S = C⋅Ifault⋅√t
C...constant depending on material, type and design of a cable
I... RMS value of fault current in kA during fault time
t... fault time in seconds
Temperature increase allowed is typicaly Δϑ= 100-150 °C
 

Related to Fault current time 1, 3 or 5 sec

1. What is fault current time and why is it important?

Fault current time refers to the duration of a fault current, which is an electrical current that occurs when there is a fault or short circuit in a power system. It is important because it helps to determine the magnitude and duration of the current, which can impact the safety and stability of the system.

2. How is fault current time measured?

Fault current time is typically measured in seconds, and there are different time intervals that are commonly used, such as 1, 3, or 5 seconds. These intervals are chosen based on the type of power system and the equipment being used.

3. What is the difference between 1, 3, and 5 second fault current time?

The main difference is the duration of the fault current. A 1 second fault current time indicates a short duration fault, while a 5 second fault current time indicates a longer duration fault. The duration can impact the amount of damage to the system and the safety of the equipment and personnel.

4. How does fault current time affect circuit breakers?

Circuit breakers are designed to trip or open when a fault current occurs. The fault current time can impact the performance of the circuit breaker, as a longer duration fault may cause more damage and make it more difficult for the circuit breaker to interrupt the current.

5. Can fault current time be reduced or controlled?

Yes, there are various methods that can be used to reduce or control fault current time, such as using protective relays, fuses, and circuit breakers. These devices can detect and interrupt the fault current, minimizing its duration and potential damage to the system.

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