Adaptive Islanding Detection for Distributed Power Grids
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Solution Overview
Problem
Existing islanding operation detection systems for distributed power supplies face challenges in adapting to varying power grid characteristics, leading to ineffective detection and potential safety issues during grid power outages.
Innovation Solution
A detection apparatus and method that calculates frequency parameters and deviation parameters to detect islanding operations, with adaptive time gap changes and reactive power injection, allowing for accurate detection and prevention of islanding states in distributed power supplies connected to diverse power grids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed time gap is used between first term and second term for deviation parameter calculation, then the detection system is simple to operate, but it cannot adapt to varying power grid characteristics and flicker conditions
Solution Approach 1:
The patent applies dynamics by making the time gap between the first term and second term adjustable rather than fixed. The time gap change unit dynamically modifies this interval based on detected flicker conditions and power grid characteristics, allowing the detection system to adapt to varying operational environments while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent changes the time gap parameter based on detected flicker and power grid characteristics. By adjusting this temporal parameter dynamically, the system adapts to different power grid conditions without requiring complete system redesign, thus improving versatility while controlling complexity.
2Reliability
If a fixed second term length is used for frequency parameter calculation, then the calculation process is simple, but it cannot effectively detect islanding operations under varying grid conditions
Solution Approach 1:
The term change unit dynamically adjusts the second term length based on detected flicker and power grid characteristics. This dynamic adjustment improves islanding detection reliability under varying conditions while maintaining a relatively simple calculation framework that does not require complete redesign for different scenarios.
Solution Approach 2:
The patent changes the second term length parameter adaptively based on operational conditions. This parameter adjustment allows the system to maintain high detection reliability across different power grid characteristics without significantly increasing calculation process complexity.
3Measurement precision
If reactive power injection is used for islanding detection, then detection accuracy is improved, but flicker may occur in the power supply
Solution Approach 1:
The patent implements feedback by monitoring the power supply for flicker conditions and using this information to adjust the time gap and second term length parameters. When flicker is detected, the system modifies its detection parameters to reduce reactive power injection effects, thereby maintaining detection accuracy while minimizing harmful flicker in the power supply.
Solution Approach 2:
The patent changes detection parameters (time gap and second term length) in response to flicker conditions. By adjusting these parameters dynamically, the system maintains islanding detection accuracy while reducing the occurrence and severity of flicker in the power supply during reactive power injection.
Data Source
AI summary
An islanding operation is detected appropriately through interconnection to the power grid which may have various characteristics. A detection apparatus is provided, which includes a frequency parameter calculation unit configured to calculate frequency parameters according to frequencies of power supplied by a power supply, a deviation parameter calculation unit configured to calculate a deviation parameter according to a frequency deviation based on the frequency parameters in a first term and the frequency parameters in a second term earlier than the first term, an islanding operation detection unit configured to detect whether the power supply is in an islanding operation based on the deviation parameter, and a time gap change unit configured to change a time gap between the first term and the second term.