New Energy Grid Overvoltage Identification Using PLL Dynamics
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Solution Overview
Problem
Existing research lacks a method for identifying a dominant overvoltage in high-proportion new energy power systems, particularly focusing on the correlation relationships among different devices and buses in the power grid, and the dynamics of phase locked loops (PLL), which hinders effective safety and stability analysis and control.
Innovation Solution
A method and system for identifying dominant overvoltage in high-proportion new energy power systems by determining voltage amplitudes, establishing a voltage analytical calculation model considering PLL dynamics, and using an overvoltage limit ratio to identify dominant voltage constraints, focusing on VSC grid-connected systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing research focuses on calculation and evaluation of degree of overvoltage, then overvoltage assessment capability is improved, but identification of dominant overvoltage and correlation relationships among different devices and buses remains insufficient
Solution Approach 1:
The patent segments the overvoltage analysis by dividing the power system into multiple devices and buses, and further segments the overvoltage characteristics into different types (temporary overvoltage, sustained overvoltage, etc.). This segmentation enables independent analysis of each segment while maintaining the ability to identify correlation relationships among them through the dominant overvoltage identification mechanism.
Solution Approach 2:
The patent introduces an intermediary mechanism - the dominant overvoltage identification module that acts as a mediator between the overvoltage detection system and the control system. This intermediary analyzes the correlation relationships among different devices and buses, identifies the dominant overvoltage sources, and provides targeted control recommendations, thereby recovering the lost information about correlation relationships.
2Reliability
If research on dominant overvoltage identification considering PLL dynamics is conducted, then safety and stability control is improved, but system complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-establishing the voltage analytical calculation model that incorporates PLL dynamics characteristics before actual overvoltage events occur. The model pre-identifies potential dominant overvoltage sources and their correlation relationships, allowing the system to respond quickly and accurately when overvoltage events actually occur, thereby improving reliability without proportionally increasing operational complexity.
Solution Approach 2:
The patent utilizes parameter changes by incorporating PLL dynamics parameters (such as phase-locked loop bandwidth, damping ratio, etc.) into the voltage analytical calculation model. By adjusting and optimizing these parameters, the system achieves accurate dominant overvoltage identification while maintaining manageable system complexity through parameter-based modeling rather than complex structural changes.
Data Source
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AI summary
A method and system for identifying dominant overvoltage of a high-proportion new energy power system. The method comprises: respectively determining a new energy machine end voltage amplitude value and an alternating current bus voltage amplitude value (101); determining an overvoltage limit value ratio according to a ratio of the new energy machine end voltage amplitude value to the alternating current bus voltage amplitude value (102); determining a threshold overvoltage limit value ratio (103); respectively determining a maximum new energy machine end voltage value and a maximum alternating current bus voltage value that can be borne by a new energy machine end and an alternating current bus (104); and performing dominant voltage safety constraint identification according to the overvoltage limit value ratio, the threshold overvoltage limit value ratio, the maximum new energy machine end voltage value, and the maximum alternating current bus voltage value, and determining an identification result (105). According to the method, the overvoltage limit value ratio is used as an index, and powerful support can be provided for analysis and control of safety and stability of the high-proportion new energy power system.