Power Quality Grading Using Harmonic Current and Voltage Compensation
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Solution Overview
Problem
Existing power grid systems face low compensation accuracy and speed for harmonic voltage and current due to the use of hysteresis comparators and serial active power filters in traditional methods.
Innovation Solution
A method and apparatus that adjusts harmonic current and voltage through comparison with actual compensating currents and switch actuation durations, using hysteresis comparators and parallel active power filters, to improve compensation accuracy and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hysteresis comparator is used to compensate harmonic current detected by dq0 transformation method, then compensation is achieved, but compensation accuracy of harmonic current is low
Solution Approach 1:
The patent changes the control parameter from simple hysteresis comparison to a comprehensive evaluation system that considers multiple parameters including harmonic current magnitude, voltage magnitude, and power factor. This multi-parameter approach enables more accurate determination of power quality levels and improves compensation accuracy by adapting control strategies based on actual grid conditions.
2Measurement precision
If serial active power filter is used to compensate harmonic voltage detected by dq0 transformation method, then compensation is achieved, but compensation accuracy of harmonic voltage is low
Solution Approach 1:
The patent implements dynamic control by continuously monitoring multiple parameters (harmonic current, voltage, power factor) and adjusting the compensation strategy in real-time based on the determined power quality level. This dynamic adaptation allows the system to optimize compensation accuracy for harmonic voltage under varying grid conditions, rather than using a fixed compensation approach.
3Productivity
If dq0 transformation method is used to detect harmonic current and voltage, then detection is achieved, but computation amount is large
Solution Approach 1:
The patent segments the power quality assessment into discrete levels (first through fourth levels) based on threshold comparisons of harmonic current, voltage, and power factor. This segmentation approach simplifies computation by replacing complex continuous analysis with discrete level determination, reducing computational burden while maintaining detection capability.
Data Source
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AI summary
The present application relates to a power quality level determining method and apparatus for a power grid, a device, and a storage medium. The method includes: obtaining a harmonic current to be compensated and a harmonic voltage to be compensated in a power grid; performing a compensation processing on the harmonic current to be compensated according to a compared result of the harmonic current to be compensated and an actual compensating current, to obtain an adjusted harmonic current, where, the actual compensating current comprises an actual output current of a current adjusting inverter; performing a compensation processing on a harmonic voltage to be compensated according to the harmonic voltage to be compensated and a pre-obtained object switch actuation duration, to obtain an adjusted harmonic voltage, where, the object switch actuation duration comprises a duration when a plurality of groups of power switch devices in an active power filter are controlled to be turned on or off; and determining an object power quality level for the power grid according to the adjusted harmonic current and the adjusted harmonic voltage. The method can improve compensation accuracy of the harmonic voltage and harmonic current in the power grid.