Determining capacity of end line reactor 1

[Tofeil]

Dear friends
I have a 400-kV transmission line for a simulation which conductor type and tower configuration specified and compenseted through a end line reactor. how to determine a nominal capacity for the corresponding reactor in order to reduce switching overvoltage surges? The end line is opened without any load.
Regards

 

[magoo2]

The reactor is intended to reduce the steady-state voltage rise (Ferranti effect). You can calculate the receiving end voltage with and without a reactor. You can also estimate the steady-state reactive flow and size the reactor close to this.

I don't believe it will reduce the switching surge transient overvoltages or at least not in a significant way.

 

[QBplanner]

Switching over voltage contains two basic components: forced component and free component. High voltage line reactor is to control the forced component portion.

 

[magoo2]

Hey QB,

Can you elaborate on what you mean my free and forced components?

 

[QBplanner]

free "transient component" forced "steady state component". Two components superpose together would be teh switching transient

 

[Tofeil]

Thank you Dear QBplanner
I know about free and forced component, but my questions is following:
1- how to determine a nominal capacity for the EHV shunt reactor, while the line's load not assigned and my EHV line only recognized through conductor type and tower configuration?
2- how to determine capacity for the line by conductor type and tower configuration without load characteristics?
Thank you again!

 

[waross]

Line capacity is often limited by the ability of the On-Load-Tap-Changer to compensate for the voltage drop caused by the load. Reducing reactive current flow reduces the voltage drop under load and allows a higher capacity with a given tap changer.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[QBplanner]

here, we compensate EHV transmission system(Mesh) using 80% compensation level. It is a rule of thumb. 40% on each line end and normally one is switched and one is fixed. Hope you can size the reactor.
For some radial EHV lines, we use different schemes based on the system requirements. we apply different sizes other than 40% 40%. it depends on the network you have and line parameters, SLG operation for neutral reactor requirements, reactive Var control via the lines, normal operation voltage control ,generator stability, power frequency O/V control , switching transient concerns and others. I knew in a sub we put in a small EHV reactor only to accommdate the neutral reactor and SLG operation.