Synchronous Machine Grid Stability via Condenser Mode
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Solution Overview
Problem
Alternative energy power generation systems using synchronous generators face instability due to leading power factors caused by long transmission lines, which can lead to system instability during light loads, necessitating the disconnection of transmission lines and inefficient energy use.
Innovation Solution
A power generation system with a synchronous machine that can selectively operate as both a synchronous generator and a synchronous condenser, allowing for adjustment of power factor and voltage, using existing equipment to maintain system stability and energy efficiency by injecting reactive power at the point of generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If synchronous generators are used in alternative energy power generation systems, then the generators can be directly connected to the grid with predictable behavior, but long transmission lines create a leading power factor that causes system instability
Solution Approach 1:
The synchronous machine is designed to perform multiple functions: it can operate as a synchronous generator to produce electrical power from the prime mover, or as a synchronous condenser to provide reactive power compensation. This multi-functionality allows the same equipment to both generate power and stabilize the power factor, resolving the contradiction between direct grid connection and leading power factor instability
Solution Approach 2:
The system changes the operating parameters of the synchronous machine by switching between two modes: in generator mode, the machine operates with specific excitation and load parameters; in condenser mode, the excitation and reactive power parameters are adjusted to compensate for the leading power factor. This parameter adjustment allows the system to maintain stability while using long transmission lines
2Reliability
If transmission lines are disconnected to prevent leading power factor instability during light loads, then system stability is maintained, but efficient use of alternative energy sources is reduced
Solution Approach 1:
The harmful effect of the leading power factor is extracted and compensated for by the synchronous machine operating in condenser mode. By isolating the reactive power compensation function to a specific component (the synchronous machine), the system can maintain transmission lines connected for energy efficiency while separately addressing the stability issue through reactive power management
Solution Approach 2:
The synchronous machine acts as an intermediary between the prime mover and the grid, providing reactive power compensation to offset the leading power factor effect of long transmission lines. This intermediary function allows the transmission lines to remain connected and transmit active power efficiently while the synchronous machine mediates the power factor issue
3Object-generated harmful factors
If reactive loads or reactors are used to compensate for leading power factor, then power factor adjustment is achieved, but equipment complexity and cost increase
Solution Approach 1:
Instead of adding separate reactive loads or reactors for power factor compensation, the invention utilizes the existing synchronous machine to perform both power generation and reactive power compensation. This eliminates the need for additional compensation equipment, reducing system complexity and cost while achieving the same power factor adjustment effect
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 efficient use of alternative energy sources by maintaining system stability and preventing unnecessary disconnection of transmission lines, allowing for continuous energy supply and improved grid stability through local or remote control of reactive power.
Implementation Method 1
the synchronous machine is coupled to the prime mover and acts as a synchronous generator to supply power to the electrical grid
Implementation Method 2
A synchronous machine for power generation typically comprises a rotor holding a field winding which is magnetised by an excitation current
Data Source
AI summary
A power generation system is disclosed for supplying power to an electrical grid. The system comprises a synchronous machine and coupling means for coupling the synchronous machine to a prime mover. Control means are provided to control the system such that the system is selectively operable in two modes. In the first mode, the synchronous machine is coupled to the prime mover and acts as a synchronous generator to supply power to the grid. In the second mode the synchronous machine is decoupled from the prime mover and acts as a synchronous condenser. This can allow parameters of the grid, such as power factor and voltage, to be adjusted.