Grid Frequency Load Control to Limit Flicker Distortion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power controller devices for AC power grids face limitations in responding to frequency instability, leading to potential equipment trips and system collapse, and introduce unwanted distortions like flicker due to synchronized waveform chopping.
Innovation Solution
A power control device with a frequency sensing block and logic block that adjusts load consumption based on grid frequency deviations, using processors and power electronics to selectively reduce RMS voltage without introducing a DC component, and implementing a modulation strategy to randomize the responses of multiple devices to minimize distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power controller devices chop voltage waveforms synchronously to reduce load consumption during frequency instability, then the aggregate load reduction compensates for power generation imbalance, but unwanted distortions such as flicker are introduced in the AC power grid
Solution Approach 1:
The patent applies periodic action by implementing modulation strategies that randomize the waveform chopping timing across multiple power controller devices. Instead of all devices chopping synchronously, they operate at different phases of the voltage waveform, distributing the load reduction effect over time while maintaining the aggregate compensation effect. This periodic but desynchronized approach reduces flicker distortion while preserving grid stability benefits.
Solution Approach 2:
The patent applies local quality by allowing each power controller device to independently determine its own chopping strategy based on local conditions. Each device adjusts its waveform reduction pattern individually rather than following a centralized synchronous command, enabling localized adaptation that collectively achieves grid-wide stability while minimizing individual device contribution to flicker distortion.
2Reliability
If speed governors are used to regulate power output of generation units in response to frequency variation, then the power generation compensates for load imbalance, but the response is slow due to mechanical operations required for speed adjustment
Solution Approach 1:
The patent replaces the mechanical speed governor system with an electronic control approach. Power controller devices use electronic sensing and control circuitry to detect frequency deviations and rapidly adjust load consumption accordingly. This electronic substitution eliminates the mechanical inertia and slow response characteristics of traditional speed governors, enabling much faster response to frequency instability events.
Solution Approach 2:
The patent applies preliminary action by having power controller devices continuously monitor grid frequency and stand ready to adjust load consumption immediately upon detecting frequency deviations. Rather than waiting for mechanical systems to respond, the electronic control system is pre-positioned to execute load reduction commands instantly, providing advance compensation for generation imbalances before they escalate into severe instability events.
3Productivity
If power controller devices reduce RMS voltage supplied to electrical load to reduce power consumption, then the load dynamically responds to compensate for power generation deficit, but the same portion of voltage waveform is chopped-off by every device creating distortions
Solution Approach 1:
The patent applies asymmetry by introducing intentional asymmetry in the waveform chopping patterns across different power controller devices. Instead of all devices chopping the same symmetric portion of the voltage waveform, each device is configured to chop different portions or phases of the waveform. This asymmetric approach distributes the distortion effects and prevents the coherent addition of identical waveform modifications that cause severe flicker and distortion.
Solution Approach 2:
The patent applies dynamics by making the waveform chopping strategy adaptive and variable rather than static and uniform. Power controller devices dynamically adjust their chopping patterns based on real-time grid conditions, allowing the system to optimize between load reduction effectiveness and distortion minimization. This dynamic approach enables the system to respond flexibly to changing operating conditions while maintaining productivity.
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
The solution effectively compensates for power generation imbalances, reduces the likelihood of aggregate load creep-up, and maintains acceptable flicker levels, enhancing grid stability and reducing the risk of system instability while minimizing distortions in the AC power grid.
Implementation Method 1
the power electronics of the power controller are configured to lower the RMS (root mean square) voltage supplied to the electrical load, in order to lower its electrical consumption, which may involve simply chopping-off segments of the voltage waveform
Implementation Method 2
When the AC power grid experiences a significant imbalance due to a power generation deficit, the kinetic energy will be tapped and converted in electricity to feed the load, thus compensating the power generation deficit temporarily
Data Source
AI summary
A power control device for use in an AC power grid for regulating an electrical power a load that is supplied by the AC power grid consumes. The power control device has a frequency sensing functional block for detecting a deviation of the grid frequency from a nominal grid frequency and a logic functional block for performing a load adjustment process during which the power the load consumption is reduced. The load adjustment process is based at least in part on the variation of the frequency of the AC power grid. The load adjustment process is design such that for a plurality of power control devices the individual response produce a grid-wide effect that compensates imbalance between power generation and load in fashion that may reduce unwanted distortion in the AC power grid, such as flicker.