I am getting a maximum trip time of 2 seconds. The protective device arcing fault current is 4kA.
As I have put only relay in the upstream and no breaker is there. Can I safely assume that the upstream device will trip prior to 2 sec as the protective device arcing fault current is around 4kA...
I have been analysing the arc flash results and I could see fuse on the primary side has tripped before the breaker on the secondary side of T2 transformer. Please find reference photo. Both the buses are seeing the same bolted and arcing fault. LV breaker(C1) on transformer side(T1) is...
I have transformer of 75kVA, 480/208V and z=3.6%. I am calculating the breaker settings Ir, Isd and Ii.
My breaker is of 250A.
Based on FLA, I am setting Ir and Ii by seeing fault current. I am confused about setting Isd. How should I set my values of Isd?
Can you please give me an example of...
I have transformer of 4190(Full load kVA) and Voltage is 21500V. FLA is coming out to be around 112.5A. Phase relay is kept at a CT ratio of 200/1 and Ground relay is kept at a CT ratio of 50/1.
Should I update the FLA(Amps) here as per my transformer data for both phase and ground elements?
I ran a study and I could see my SLG current coming out to be higher than the three phase current. This is first time, I encountered such scenario running studies. Is it because of impact of impedances? Can someone please give me an explanation or an article to read to understand such scenario...
I am trying to run arc flash analysis in SKM. My system is at 13.2 kV. Do I need to define voltage tolerances in EPRI method too if I am running my system at 13.2kV? What tolerance range is considered to calculate incident energy?
Are there any specific standards, that specify the allowable starting motor voltage drops, the behaviour of load torque w.r.t motor torque, behaviour of motor torque and acceleration torque and, variation of speed. I have ran studies for the first time on SKM and couldn’t find much on it.
I have a motor of 44kW rating. I am choosing a typical data in SKM for my load(fan model) and motor model for TMS studies. And I could see an error of motor torque could be smaller than the load torque. What should I do to mitigate this error? I tried using different model, but still couldn’t...
I am new to load flow analysis.I have been told to maintain a voltage of 0.95 pu on my buses. I ran load flow studies on SkM and could see that there is much voltage drop on my buses. I have modelled utility as an infinite bus. What should I do to bring the voltage drop at my downstream buses...
