Excitation system ceiling voltage

Our GT Generator will be upgraded with the turbine Advanced gas path.
The Generator output will increase to 296 MW , the power factor of 0,85 will require 184 MVar instead of 171 MVar that are now capable.
GE proposed to replace the Excitation transformer (PPT) since it will require 3150 KVA instead of 2600 KVA.

Due to the high costs imposed GE came with another proposal

TO decrease the excitation ceiling voltage from 2 pu to 1,92 pu

Can you share similar experiences?

From the little things i red, the higher the ceiling voltage (maximum votlage supplied from the excitaiton to the GEN filed) the quicker the AVR control.
Hello Stratford,

What is the type of excitation systems that you got?

According to your description looks like Potentiel bus fed ?
Is it a static excitation
A brushless excitation?

Also is the AVR EX2100E?

About ceiling PARAMETERS ( voltage/current) i suggest you to have a read on this document:

I will have a better look on what it returns and let you know


Can be also a coumpound source excitation ?

3.2 Compound-source rectifier system:
•power to the exciter is formed by utilizing current as well as voltage of the main generator
•achieved through a power potential transformer (PPT) and a saturable current transformer (SCT)
•the regulator controls the exciter output through controlled saturation of excitation transformer
•during a system fault, with depressed generator voltage, the current input enables the exciter to provide high field forcing capability
An example is the GE SCT-PPT.