Renewable Plant Frequency Response Control Beyond Deadband
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing renewable energy plant control systems fail to initiate real power response immediately when frequency deviates outside the deadband and do not sustain the response until the frequency returns within the deadband setting, leading to instability in power system frequency.
Innovation Solution
A method and system that measure frequency deviations and power output, generate an error signal within predetermined limits, and apply a control signal to the intermittent energy source to control power output, ensuring immediate and sustained frequency response by disregarding updated AGC commands and smoothly ramping power generation when frequency returns within the deadband.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing control systems use conventional frequency response control with deadband settings, then the plant operates normally under standard conditions, but the real power response does not begin immediately when frequency deviates outside the deadband
Solution Approach 1:
The control system pre-calculates and stores the difference signal between power reference and measured power output before frequency deviation occurs. When frequency deviates outside the deadband, this pre-computed signal is immediately applied without calculation delay, enabling immediate response while maintaining reliability through deadband filtering during normal operation.
2Adaptability or versatility
If existing control systems allow AGC commands to update power references continuously, then the plant can adapt to changing grid conditions, but the frequency response is overridden and not sustained until frequency returns within deadband
Solution Approach 1:
The control system dynamically switches between two operational modes: during frequency deviation outside deadband, it enters frequency response mode where AGC commands are blocked and the pre-computed difference signal is held constant to sustain response; when frequency returns within deadband, it transitions back to normal AGC control mode, allowing continuous adaptation to grid conditions.
3Reliability
If the control system applies frequency droop response to power reference, then frequency stabilization is achieved, but abrupt transitions occur when frequency returns within deadband
Solution Approach 1:
The control system prepares a ramped version of the difference signal in advance, creating a smooth transition profile before frequency returns to the deadband. This pre-prepared ramp signal cushions the transition, preventing abrupt changes in power output while maintaining frequency stabilization benefits.
Data Source
AI summary
A method for providing frequency response for a plant coupled to an electric power grid, the plant having an intermittent energy source, comprising: measuring frequency of the power output from the plant and determining a first difference between the measured frequency and a frequency reference; measuring power output from the plant and storing the measured power output as a stored value; while the first difference is within a deadband, determining a second difference as a difference between a power reference and the measured power output; while the first difference indicates over-frequency, determining the second difference as a difference between the stored value and the measured power output; while the first difference indicates under-frequency, setting the second difference equal to the power reference; generating an error by limiting a sum of the first and second differences between error limits; generating a control signal; and, applying the control signal to the source.