Harmonic Filter Bank Control for Renewable PQ Curve Compliance
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Solution Overview
Problem
Renewable energy power systems, such as wind turbines with DFIG configurations, face challenges in maintaining steady-state reactive power capabilities, which can move out of the required active power-reactive power curve at low or high active power outputs, necessitating an improved system for controlling harmonic filter banks to meet PQ requirements.
Innovation Solution
A method and system that utilize a controller to determine and adjust the number of active harmonic filter banks in operation based on actual power output and the number of online renewable energy assets, comparing required and actual filter banks to either maintain or adjust their operation by closing or tripping additional filter banks, using state and availability feedbacks to manage pole disagreements and ensure reactive power capabilities align with the PQ curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If harmonic filter banks are enabled to provide steady state reactive power output, then reactive power capability is improved, but the farm reactive power capability moves out of the required PQ curve at low or high active power output
Solution Approach 1:
The patent applies dynamics by making the filter bank configuration adjustable based on operating conditions. The system dynamically switches between different filter bank configurations (full configuration, first reduced configuration, second reduced configuration) depending on the active power output level, allowing the reactive power capability to adapt and remain within the required PQ curve across different operating points.
Solution Approach 2:
The patent changes the parameter of filter bank configuration based on the active power output. By switching between different filter bank configurations corresponding to different active power ranges, the system adjusts the reactive power output parameter to maintain compliance with the PQ curve requirements while still providing necessary reactive power support.
2Manufacturing precision
If filter banks are adjusted to maintain PQ curve compliance, then reactive power capability alignment is improved, but system complexity increases due to multiple configurations and control logic
Solution Approach 1:
The patent segments the filter bank operation into distinct configurations corresponding to different active power ranges. By dividing the operating range into segments (high active power, medium active power, low active power) and assigning specific filter bank configurations to each segment, the control system manages complexity through structured segmentation rather than continuous adjustment.
Solution Approach 2:
The control system dynamically selects the appropriate filter bank configuration based on the current active power output level. This dynamic switching between predefined configurations simplifies the control logic compared to continuous adjustment, as the system only needs to select from discrete, pre-optimized configurations based on operating conditions.
Data Source
AI summary
A method for controlling a renewable energy power system having at least one renewable energy asset connected to a power grid includes receiving, via a controller, at least one of an actual power output of the renewable energy power system or a number of the plurality of renewable energy assets that are online. Further, the method includes determining, via the controller, an actual number of active harmonic filter banks in operation based on at least one of the actual power output and the number of the plurality of renewable energy assets that are online. Moreover, the method includes adjusting or maintaining, via the controller, the actual number of active harmonic filter banks in operation to maintain steady state reactive power capabilities of the renewable energy power system to meet reactive power-active power curve requirements for the renewable energy power system.