impact of load growth on short-circuit MVA in constrained grids

[KojoSincal]

In a grid system experiencing load growth, what happens to the short-circuit MVA (SC MVA) at a particular bus if:
No new transmission capacity is added
A previously offline generator is brought online to meet the increased demand
How does bringing this additional generator online impact the SC MVA at that bus?
I'm particularly interested in understanding the implications of a decreasing SC MVA in this scenario. What challenges can it lead to in terms of grid stability, power quality, and future integration of renewable energy?
Looking forward to insights from the engineering community on this.

 

[jghrist]

If generation is brought on line, it provides an addition source of fault current, so the SC MVA will increase.

 

[waross]

Not to contradict jgrist but to add to his post.
The Available Short Circuit Current (ASCC) will not exceed the ASCC of the transformer calculated on the basis of an infinite bus.
If you are able to withstand the max ASCC of the transformer, you are safe.
The ASCC may be less with less generation online.
I generally look at the transformer ASCC.
If the calculated ASCC is greater than the switchgear rating, then I look at mitigating factors (usually feeder impedance) that may reduce the ASCC to below the rating of the switchgear.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[cranky108]

If the new generation that is brought on is of the inverter type, and an older conventual generation is taken off, then the fault current could go down.
Just use the infinite bus method.

 

[Pandit1]

When no new transmission capacity is added, bringing a previously offline generator online to meet increased demand typically increases the short-circuit MVA (SC MVA) at the bus. This is because the additional generator adds more fault current contribution to the system.

Implications of Decreasing SC MVA:

Grid Stability: Decreasing SC MVA can lead to instability issues, as the system may not handle large disturbances effectively.
Power Quality: Lower SC MVA can result in voltage sags and swells, affecting sensitive equipment.
Future Integration of Renewables: It can pose challenges for integrating renewable energy sources, which often require robust short-circuit strength for stable operation and protection coordination.
These challenges underscore the need for careful planning and potentially upgrading transmission capacity to maintain a resilient and high-quality power grid.