GE EX2100e Data Sheet

GE Energy 
 

EX2100e Excitation Control for 
Steam Turbine Generators 
  

The EX2100e excitation control is GE Energy’s advanced 
platform for generator excitation systems. EX2100e builds on 

the EX2100 experience of over 700 units in gas, steam, and 

hydro applications for new units and upgrades, in addition to 
GE’s 40 years of experience with over 6,000 excitation 

systems in 70 countries. 

 
The “e” designates enhanced technology with a new 

controller from the Mark* VIe controller family and ControlST* 

software suite for commonality with GE’s family of plant 
control systems. In addition, the EX2100e offers a brushless 

dual redundant regulator option for cost effective reliability. 

 

Architecture

 

The system consists of one or multiple controllers, a 

protection module, power conversion bridges, and the power 

magnetics / transformers. Typical functions performed in the 
controller and protection system include: 

Control 
•  Automatic voltage regulator 

-  Reactive current compensator 

-  Volts per hertz limiter 

-  Overexcitation limiter 
-  Underexcitation limiter 

•  Manual field voltage regulator 
 

Protection 
•  Volts per hertz, dual level (24EX) 
•  Loss of excitation (40EX) 
•  Bridge ac voltage phase unbalance (47EX) 
•  Generator overvoltage (59EX) 
•  Off/online overexcitation (76EX) 

 

The software can also include the power system stabilizer 

(PSS). This enables the generator to produce and transmit 
more power in a stable manner by reducing low frequency 

rotor oscillations. Power system studies are available to 

optimize the tuning of the stabilizer for the best performance. 
These studies include computer simulations for transient 

stability analysis. Field testing services are also available for 

commissioning to verify and document system performance 
to existing specifications.

 

 

 
 

 

 

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Redundancy

 

Large steam turbine generators have potential source (bus 

fed) static excitation controls with power potential 
transformer to step down the bus voltage to a suitable 

voltage for the excitation controls. These controls are 
normally supplied with either a full multi-bridge or a warm 

backup for redundancy to maximize system reliability. 

Redundant controls include online repair capability for circuit 
boards and power supplies. Multi-bridge units can support 

online repair of the power conversion bridges. Units with 

redundant rectifier cooling fans can also be replaced online 
to support equipment availability. 

 

Medium and small steam turbine generators often have 
brushless excitation controls with an ac-rotating generator 

connected to the shaft of the main generator. These units are 

equipped with the EX2100e excitation control brushless 
regulators. They are normally supplied as simplex, non-

redundant, control systems, but are also available in warm 

backup configuration for redundancy. They share the same 
overall control design and software features as static exciter 

systems for consistency. Steam turbine generators contain: 

 

 
Redundancy 

Large 

Potential source static exciter  Multi-bridge 

Median and 

small 

Brushless regulator or 

potential source static exciter 

Simplex and 

warm backup 

option 

 

 
 

 

 
 

GEA-S1244 

fact sheet