Power System Rotor Angle Determination Using Permanent Magnet Signalling Generator
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Solution Overview
Problem
Existing methods for determining the load angle and rotor angle in electrical power generators, especially during high load conditions and transient periods, are inaccurate due to magnetic saturation and require costly modifications, making them unsuitable for small synchronous generators and smart grids.
Innovation Solution
A power system comprising a synchronous electrical generator with a permanent magnet signalling generator coupled to its shaft, and an angle computation unit that calculates the rotor or load angle using voltage differences and space vector computations, allowing for accurate determination during both steady and transient states without requiring additional power supplies or external components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional load angle determination methods are used during high load conditions and transient periods, then the system can operate continuously, but the measurement precision deteriorates due to magnetic saturation
Solution Approach 1:
A permanent magnet signalling generator is introduced as an intermediary device coupled to the rotor shaft. This signalling generator produces a reference voltage signal that directly reflects rotor position without being affected by magnetic saturation in the main generator, thereby enabling accurate load angle measurement during transient periods and high load conditions
Solution Approach 2:
The permanent magnet signalling generator creates a simplified copy of the rotor's magnetic field characteristics. By using permanent magnets on the rotor that generate a proportional voltage signal, the system obtains a reliable reference that mirrors rotor position information without the complexity and saturation issues of the main generator's magnetic circuit
2Measurement precision
If existing load angle determination techniques are implemented, then angle measurement can be performed, but the device complexity and cost increase due to additional power supplies and external components
Solution Approach 1:
The permanent magnet signalling generator serves multiple functions simultaneously: it acts as both a position sensor and a reference voltage source. The same rotor shaft that drives the main generator also drives the signalling generator, eliminating the need for separate positioning mechanisms and reducing overall system complexity
Solution Approach 2:
The signalling generator is self-powered through its coupling to the rotor shaft. It generates its own reference voltage signal through electromagnetic induction as the rotor rotates, eliminating the need for external power supplies or batteries that would otherwise be required for active sensing systems
3Ease of operation
If voltage magnitude-dependent methods are used for angle determination, then calculations can be performed during steady state, but the measurement precision deteriorates during transitional state operation when voltage magnitude changes
Solution Approach 1:
The patent replaces voltage magnitude-based calculations with voltage angle-based calculations using space vector methodology. By computing the angle between voltage vectors rather than relying on voltage magnitudes, the system achieves immunity to voltage fluctuations and maintains measurement precision during transient operations
Solution Approach 2:
The calculation methodology transitions from using voltage magnitude parameters to using voltage angle parameters. This parameter change fundamentally alters the computation approach, making it insensitive to voltage magnitude variations while maintaining accuracy during both steady-state and transient conditions
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
This approach provides accurate and cost-effective determination of load and rotor angles, independent of voltage magnitude, enabling reliable out-of-step condition detection and reducing noise interference, suitable for small generators and smart grids.
Implementation Method 1
a permanent magnet signalling generator, coupled to the shaft; and an angle computation unit configured to calculate a rotor angle and/or load angle based on a voltage from the permanent magnet signalling generator
Data Source
AI summary
A power system includes a synchronous electrical generator having a rotor driven by a shaft; a permanent magnet signaling generator, coupled to the shaft; and an angle computation unit configured to calculate a rotor angle or load angle based on a voltage from the permanent magnet signaling generator and a voltage from the synchronous electrical generator.