Synchronous Generator Conversion to Condenser Using Variable Frequency Drive
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Solution Overview
Problem
Retired synchronous generators require time-consuming and costly processes to be decoupled from turbines and brought to operational speed for use as synchronous condensers, often necessitating dedicated starting motors that need to withstand various operational events, which is inefficient and costly.
Innovation Solution
A system comprising a synchronous generator decoupled from a turbine, equipped with a variable frequency drive and an exciter, controlled by a controller to accelerate the rotor to operational speed, allowing the generator to function as a synchronous condenser without the need for additional starting motors, using a movement assembly with thrust bearings, steady rest bearings, and turning gears for support and initial speed facilitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a dedicated starting motor is attached to the rotor shaft to bring the generator to operational speed, then the generator can be brought to operational speed, but the assembly process becomes time-consuming and the motor design becomes complex
Solution Approach 1:
The generator uses its own stator windings to generate the starting torque needed to rotate the rotor, eliminating the need for an external starting motor. The controller energizes the stator windings to create a rotating magnetic field that drives the rotor to operational speed, allowing the system to start itself without additional hardware assembly.
2Speed
If a dedicated starting motor is attached to the rotor shaft, then the generator can be brought to operational speed, but the motor needs to be designed to withstand various operational events increasing complexity
Solution Approach 1:
The generator utilizes its existing stator windings and controller to generate starting torque, eliminating the need for a separate starting motor that would require complex design to withstand operational events. The stator windings are energized by the controller to create a rotating magnetic field that safely accelerates the rotor without requiring additional motor components.
3Speed
If additional starting hardware is installed on the rotor shaft, then the generator can be brought to operational speed, but the conversion process becomes costly
Solution Approach 1:
The generator is converted to synchronous condenser mode by utilizing its existing stator windings and controller to provide starting torque, eliminating the need for expensive additional starting hardware. The controller energizes the stator windings to create a rotating magnetic field that accelerates the rotor, providing a cost-effective conversion that requires minimal additional investment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the conversion of synchronous generators to synchronous condensers with minimal disruption and cost, allowing for efficient generation or absorption of reactive power, and facilitates easy reconfiguration back to synchronous generation mode without additional hardware installation.
Implementation Method 1
A variable frequency drive, coupled to the generator, provides electrical energy to the stator to turn the rotor at a rotational speed that is proportional to a frequency of operation of the variable frequency drive
Implementation Method 2
An exciter facilitates injection of excitation current into the generator rotor at any speed of rotation including standstill
Data Source
AI summary
An approach for converting a synchronous generator to a synchronous condenser is disclosed. In one aspect, a variable frequency driver is used to provide a starting power source to accelerate a synchronous generator decoupled from a turbine to an operational speed to act as a synchronous condenser. In another aspect, the synchronous condenser can be recoupled back to the turbine to form the synchronous generator.