Real-Time Voltage Support Strength Assessment for Renewable Grid Buses
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Solution Overview
Problem
The integration of renewable energy sources into traditional power networks faces challenges in real-time monitoring of voltage support strength due to the randomness and fluctuation of wind and solar power output, leading to difficulties in ensuring safe and reliable power transmission.
Innovation Solution
A method and apparatus for determining voltage support strength in real-time by collecting bus operating voltage and line current, calculating Thevenin equivalent potential, short circuit ratio, and critical short circuit ratio, and evaluating safety margins using electrical parameters to classify voltage support strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offline data is used to calculate short circuit ratio, then calculation accuracy is maintained, but real-time monitoring capability is lost due to time hysteresis
Solution Approach 1:
The patent transforms the static offline calculation method into a dynamic real-time calculation method by using Thevenin equivalent circuit theory. The system continuously updates the Thevenin equivalent impedance and open-circuit voltage based on real-time phasor measurement unit (PMU) data, allowing the short circuit ratio to be calculated dynamically without losing accuracy. This resolves the contradiction by making the calculation system adaptive to changing operating conditions while maintaining real-time performance.
Solution Approach 2:
The patent introduces Thevenin equivalent parameters (Thevenin equivalent impedance and Thevenin equivalent open-circuit voltage) as intermediary variables that bridge the gap between offline accuracy and real-time speed. These intermediaries are calculated from real-time measurement data and used to derive the short circuit ratio, enabling accurate real-time monitoring without direct reliance on outdated offline data.
2Measurement precision
If multiple electrical parameters are used for short circuit ratio calculation, then calculation accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent extracts and focuses on the essential parameters needed for short circuit ratio calculation by using Thevenin equivalent circuit theory. Instead of considering all possible electrical parameters, the method identifies and utilizes only the critical Thevenin equivalent impedance and open-circuit voltage, along with bus operating voltage and line current. This extraction of essential parameters reduces computational complexity while maintaining evaluation accuracy.
Solution Approach 2:
The patent changes the parameter representation from multiple raw electrical parameters to transformed Thevenin equivalent parameters. By transforming the problem into the Thevenin equivalent domain, the calculation becomes more efficient as the transformed parameters inherently capture the essential system characteristics, reducing the number of parameters that need to be processed while preserving calculation accuracy.
Data Source
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AI summary
Provided are a method, apparatus and device for determining voltage support strength of a renewable energy power system in real time, a storage medium and a computer program product. The method includes following operations. A bus real-time operating voltage and a collection line current of a monitoring point of the renewable energy power system are collected; a system's Thevenin equivalent potential of the monitoring point is calculated according to the bus real-time operating voltage and the collection line current; a short circuit ratio of the monitoring point and a critical short circuit ratio of the monitoring point are calculated according to a nominal voltage of the monitoring point, the system's Thevenin equivalent potential and the bus real-time operating voltage; a safety margin of the short circuit ratio of the monitoring point is calculated according to the short circuit ratio of the monitoring point and the critical short circuit ratio of the monitoring point; and a strength division result of the voltage support strength of the renewable energy power system is determined according to the safety margin of the short circuit ratio of the monitoring point and a set voltage support strength division criterion. The method greatly reduces electrical parameters involved in the calculation of the short circuit ratio, improves algorithm efficiency and provides technical support for strength division of the voltage support strength.