Renewable Power Plant Control Fault Detection for Undersampled Oscillations
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Solution Overview
Problem
Conventional power plant control systems are prone to instability due to undersampled oscillations of measured power characteristics, leading to erroneous operation and potential damage to the power plant.
Innovation Solution
A method and system for operating a renewable energy power plant that independently monitors measurement signals to detect undersampled oscillations, allowing for a transition to a fault mode of operation to mitigate control faults and stabilize power plant operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback control systems are used to control the WPP based on measurements of power characteristics, then the power plant can satisfy grid requirements and provide stable operation, but the system becomes susceptible to instability when measured power characteristics fluctuate at relatively high frequencies
Solution Approach 1:
The patent applies preliminary action by performing spectral analysis on the measurement signal to detect oscillations before they cause instability. The controller continuously monitors the measurement signal for oscillations having a frequency greater than half the sampling rate, and preemptively transitions to fault mode operation when oscillations are detected, preventing the feedback control system from becoming unstable.
Solution Approach 2:
The patent introduces an intermediary mechanism - the spectral analysis module - that processes the measurement signal independently of the feedback control loop. This intermediary detects oscillations and triggers a mode transition, acting as a mediator between the measurement system and the control system to prevent instability without interfering with normal feedback control operation.
2Device complexity
If the sampling rate is reduced to simplify the control system, then device complexity is reduced, but undersampled oscillations occur leading to control faults
Solution Approach 1:
The patent introduces an intermediary spectral analysis module that processes the measurement signal to detect oscillations that would otherwise be missed due to undersampling. This intermediary component enables the use of lower sampling rates while maintaining control accuracy by providing early warning of oscillations through frequency domain analysis.
Solution Approach 2:
The patent replaces the need for high-rate mechanical sampling with a spectral analysis approach. Instead of relying on the feedback control loop to sample at a high rate to detect oscillations, the system uses spectral analysis to transform the time-domain measurement signal into the frequency domain, where oscillations can be detected regardless of the sampling rate.
3Measurement precision
If the sampling rate is increased to detect oscillations, then measurement precision is improved, but the device complexity and processing requirements increase
Solution Approach 1:
The patent replaces mechanical high-rate sampling with spectral analysis of the measurement signal. By transforming the time-domain signal into the frequency domain, the system can detect oscillations with high precision without requiring a high sampling rate, thus avoiding the complexity and processing burden of high-speed sampling hardware and software.
Data Source
AI summary
Operating a renewable energy power includes receiving a measurement signal indicative of a measured power characteristic of the plant at a point of connection to a power network; controlling the plant 12) according to a normal mode of operation to provide power by determining and dispatching power set points, the power set points being determined by: acquiring samples of the measurement signal at a sample rate; and determining the power set points based on the sampled measurements and a target level for the measured power characteristic; and monitoring the measurement signal to detect an undersampled oscillation of the measured power characteristic in the sampled measurements, and thereby detecting a control fault; and then controlling the plant according to a fault mode of operation.