Voltage regulators vs. Shunt capacitors for LV

[Power0020]

I understand that with MV or HV power flow, a capacitance by end of feeder will cause voltage rise and reactive power support; however, with a LV system, since the system resistance isn't negligible, it may not be a very efficient solution.

Would a voltage regulator be more efficient in controlling the voltage with a LV feeder than a shunt capacitance? I doubt.

Any clue? past projects experience?

 

[Skogsgurra]

A shunt capacitor reduces line load. So it helps keeping voltage up. Regardless of line being inductive or resistive or a mix. Reducing line current also reduces losses.

For an HV line, a series capacitor compensates the line inductivity, and that's an entirely different story.

The answer to your question depends very much on what load you have. If mostly incandescent and heating (resistive loads), a capacitor will not help much. For asynchronous motors, it helps a lot.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[waross]

Both capacitors and voltage regulators are used.
Capacitors are used to improve lagging power factors and reduce current.
Voltage regulators are most common on long rural lines where the voltage drop becomes progressively greater the farther out from the source you are.
OLTCs can compensate for voltage drop on fairly short lines but cannot correct the progressively greater voltage drop with distance commonly seen on long rural lines.

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

 

[Power0020]

I wonder if the existing tap changer can be replaced with one having a greater voltage range? not sure if the is a common practice for distribution transformers 1~2 MVA with usually 9 step No Load Tap Changers (+/- 10%, 2.5% each step)?

 

[waross]

We have rural distribution lines 15, 20, 30 and more miles long. The loads are distributed.
The voltage drop with the distributed loads increases with the distance from the sub.
The voltage regulators are typically 10 or 15 miles out.


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

 

[prc]

It is not easy or common to replace an existing tap changer with a wider range tap changer. It requires replacement of windings also to extend tap range. A better solution is to provide a LV or HV voltage regulator. Nowadays this is becoming common due to renewable power sources at MV grid

 

[prc]

https://library.e.abb.com/public/55...ename=1LAB000588-LVR_Low-voltage-grid_en.pdf-

LV Voltage Regulators (2017-01)

https://library.e.abb.com/public/2c...ame=1LAB000589-LVR_Medium-voltage-grid_en.pdf

-MV Voltage Regulators (2017-01)