Renewable energy is continuously growing worldwide and it now starts compromising the stability of  electrical grids. Compare to fossil fuel power plants, energy production of wind and photovoltaic  energy is fluctuating. As a result, the renewable energy fluctuation is a big challenge to power  grid stability.

What is Power System Stabilizer (PSS)?

Power System Stabilizer (PSS) is the generator control equipment which are used in feedback to enhance the damping of rotor oscillation caused due to small signal disturbance.

How Power System Stabilizer (PSS) works?

It is achieved by modulating the generator excitation so as to develop components of electrical torque in phase with rotor speed deviation. The PSS thus contributes to the enhancement of small-signal stability of power systems.


  1. Improve damping of the system
  2. The dynamic stability of the system is improved
  3. Reduced power losses.


With our collaboration with Reivax, we offer the stand-alone PSS Power System Stabilizer module – PWX.  It is a stand-alone control unit that is designed to provide the PSS function with existing generator AVR/Excitation system.

The PWX module damps electromechanical oscillations that result from the operation synchronized to a system. This is possible due to the synthesis of a signal in phase with the rotor frequency, which is treated to generate a damping torque. The  PSS is based on the integral of the accelerating power and follows the PSS2B model, defined on IEEE 421.5.

It works with other existing OEM excitation system.

The user-friendly interface provide the ease interface during PSS testing and commissioning.

PSS Studies & Tuning Service:

To implement a PSS project, detailed studies and services are also the key component.  It starts from:

1. Data Collection from various constituents follow by verification.

a. to identify the model requirements and translate them into specific criteria: location of critical stations, list of critical units, list of critical components (e.g. generator, excitation system, governor…), type of models and data to be collected, and finally, types of tests to be performed. 

2. Analytical studies and Simulation

a. Linear analysis and simulation were carried out on the system.

3. Install and commission the PWX PSS module for the involved the power generator units. 

4. Offline Tuning System 

PSS parameter will be studied and determined through the modelling and simulation. 

5. Performance verification, Field tuning of PSS 

On-site tuning and testing will be carried by specialist to verify the PSS settings. 



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