Power Plant Grid Impedance Modeling for Oscillation Prediction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing models fail to explain low-frequency oscillations in power systems due to communication delay and real power effects, particularly why oscillations occur in voltage and reactive power but not in real power, and do not account for the impact of ramping up power on oscillation formation.
Innovation Solution
A method involving a computing device that receives SCADA/PMU data streams to determine grid impedance and power plant control parameters, including communication delay, and models the integrated system of power plants and the grid using Thevenin equivalent impedance, estimating voltage control droop gains and communication delays to simulate and predict oscillation events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a simplified feedback model is used to explain low-frequency oscillations, then the model can successfully explain oscillations due to communication delay and voltage control gain reduction, but the model cannot explain the real power effect on voltage or why oscillations appear only in voltage and reactive power
Solution Approach 1:
The patent transitions from a static simplified feedback model to a dynamic comprehensive model that incorporates real-time varying parameters including communication delay, voltage control gain, and grid impedance. This dynamic model successfully explains both the communication delay-induced oscillations and the real power effect on voltage, resolving the limitation of the simplified model.
Solution Approach 2:
The patent introduces additional parameters (grid impedance, communication delay, voltage control gain, real power effect) to the model to enhance its explanatory capability. By changing and incorporating these parameters, the model can now explain phenomena that the simplified model could not, including why oscillations appear only in voltage and reactive power channels.
2Measurement precision
If grid impedance is determined using SCADA/PMU data streams, then accurate grid impedance and power plant control parameters can be obtained, but the complexity of data processing and modeling increases
Solution Approach 1:
The patent employs a unified modeling framework that simultaneously determines grid impedance, voltage control droop gains, and communication delays using the same SCADA/PMU data stream. This multi-functional approach consolidates multiple determination processes into a single comprehensive model, reducing overall system complexity while maintaining high accuracy.
Solution Approach 2:
The patent uses feedback from actual power plant data streams to continuously refine and validate the grid impedance determination. By incorporating real-time measurements of voltage, reactive power, and communication delay into the modeling process, the system achieves accurate parameter determination while using the data efficiently to reduce processing complexity.
Data Source
AI summary
In some aspects, the techniques described herein relate to a method including: receiving a data stream from one or more power plants at the same location by a computing device; based on the received data stream, determining a grid impedance of the one or more power plants with respect to a grid by the computing device; based on the received data stream, determining power plant control parameters and communication delay for each of the one or more power plants; and modeling the integrated system consisting of the one or more power plants and the grid based on the determined grid impedance and the power plant control parameters by the computing device.