138 and 240 kv TX

[Windy924]

Delta 138 into substation stepping it down to 23k. Delta 240k stepping down to 23k more than one mile to tie switch from both stations that ties the 23k. I have closed/opened switch five times in the last few months. everytime seems like I am dropping load picking up load. Lots of load. could it be the two differnt primary voltages? Regulators are blocked at both stations.

 

[chris kennedy]

Welcome to the Forum. Wouldn't hurt to also post your question here.

 

[jghrist]

The secondary voltage at the 138-23 station will not be exactly the same as the voltage at the 240-23 kV station, so there will be power flow between the 138 and 240 kV systems. Even if the voltage were exactly the same magnitude, the phase angle might be different which would also produce power flow. In an extreme case, the voltage may be 30 or 60 degrees out of phase because of transformer connection differences. This case would be similar to a phase-phase fault.

Blocking the regulators will not correct the voltage difference, only keep it from changing.