Extreme Minimum Short Circuit Required for the HVDC cable

[Tinh123]

Hi,

I'm not too familiar with HVDC cable operating characteristic so any help would be appreciated. I was asked recently to determine the extreme minimum short-circuit required for the operations of the future installed HVDC line. From what I have been reading the last 2 days is that this current can be determined through the simulation of EMTP on the AC connected network (on the importing side) with the losses of multiple generation in the connected AC network. Not too certain that this is the only way to obtain the "Extreme minimum SC". Can this current be obtained through some fault analysis software like Aspen, if so, would it be accurate??

 

[itsmoked]

extreme minimum

Now that's a dichotomy you don't hear often. Can you explain what an extreme minimum short circuit is?

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[Tinh123]

Hi Itsmoked,

Thank you for your response to the subject. The definition that I received for extreme minimum short circuit current is the fault current resulted in the loss of 2 elements in the system -- N-2 conditions (N-2 would be either the losses of 2 lines, 2 generators, or combination of loss of line and critical generator). I was thinking of obtaining this value through the simulation of fault current on the bus where the HVDC inverter connected to with the 2 largest units modeled as out of service -- in Aspen Oneliner, but not quite sure this is the correct in obtaining the minimum or extreme, short circuit current. Apologize for the gibberish, but any help would be great. Thanks.

 

[bacon4life]

Which type of HVDC converter will be used? Is the minimum short circuit current related to commutation of a current source inverter?

Aspen allows sub-transient, transient or synchronous generator reactances to be used. Some users choose to substitute sub-transient values for the other two, so you will need to carefully evaluate what time frame is appropriate for the study, and then verify that the data in ASPEN for all the generators is accurate.

 

[dapotiti18]

HI,
The approximate short circuit current calculation of a hvdc cable is mathematically express as :
(Kv)*(Kv), where Kv is hvdc voltage rating

 

[Tinh123]

Hi Bacon4life,

This is a B2B HVDC converter, classical thyristor based. From what I understand is that there is a required minimum short circuit current from the inverter/converter connected AC network during the fault, so that even during fault event, the HVDC would still function and provide partial support to the connected network. How do I determine this "minimum short circuit current"? Can I simulate the fault on the connected bus in Aspen and get the minimum sc current from there??

dapotiti18, thanks for your interest in the topic, I'm curious where did you obtain the mathematical expression and can you provide the link. Thank you.

 

[bacon4life]

The engineers at ASPEN have been pretty helpful to others here in the past, so they would probably be happy to help you identify if it will give you accurate results.