Active Compensation Unit Harmonic Cancellation in Wind Farms
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Solution Overview
Problem
Wind farms face challenges in generating alternating electric currents for supply networks due to high harmonic levels, which are exacerbated by cascaded inverter embodiments, leading to non-compliance with electrical supply network requirements.
Innovation Solution
A wind farm configuration that includes a compensation wind power installation with an active compensation unit and a non-compensating wind power installation, where the active filter generates a modulated compensating component current to be superposed with non-compensating component currents, effectively reducing or eliminating harmonics at the network connection point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cascaded inverters with modulation methods are used to generate component currents, then the wind farm can feed electric current into the supply network, but the individual component currents develop high harmonics levels that negatively amplify and cause the total electric current to fail network requirements
Solution Approach 1:
The patent applies active compensation units that generate counter-harmonics to neutralize the harmful harmonics produced by the inverters. The compensation units detect the harmonic content in the component currents and inject compensating currents with opposite phase to cancel out the harmonics, thereby converting the harmful harmonic distortion into a beneficial harmonic cancellation effect that enables compliance with network requirements.
Solution Approach 2:
The active compensation units serve as intermediary devices between the inverters and the supply network. These compensation units process the component currents by filtering out harmonics and injecting corrected currents into the farm network, acting as a mediator that transforms the high-harmonic component currents into low-harmonic total current suitable for network injection.
2Manufacturing precision
If active compensation units are added to wind power installations, then harmonics can be compensated and current quality improved, but the device complexity and cost increase
Solution Approach 1:
The patent implements partial compensation by equipping only certain wind power installations within the farm with active compensation units, rather than all installations. This partial action approach achieves sufficient harmonic compensation for the total farm output while avoiding the excessive complexity and cost of universal compensation across all installations.
Solution Approach 2:
The active compensation units incorporate feedback mechanisms that continuously monitor the harmonic content of the component currents and adjust the compensation signals accordingly. This feedback control enables the system to automatically adapt to changing operating conditions and harmonic levels, maintaining current quality without requiring manual intervention or overly complex fixed compensation schemes.
Data Source
AI summary
A wind farm for feeding a total electric current into an electrical supply network at a network connection point is provided. The wind farm has at least one wind power installation designed as a compensation wind power installation and an active compensation unit to generate a compensating component current having a modulated compensation proportion. At least one wind power installation without compensation is configured to generate a non-compensating component current without a modulated compensation proportion. The compensating component current and the non-compensating component current are superposed to form the total electric current to be fed in in a farm network that connects the wind power installations. The compensating component current is generated so that the total current to be fed in influences an occurring reference current or an occurring reference voltage to achieve a prescribed current form for the reference current or a prescribed voltage form for the reference voltage.