Power Supply Islanding Detection via Frequency Change Monitoring
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Solution Overview
Problem
In electrical power supply networks, detecting islanding events quickly and reliably is challenging due to the asynchronous nature of individual zones post-overload, which can lead to frequency deviations and potential network breakdowns.
Innovation Solution
Monitoring the power supply network by determining temporal frequency change values at multiple points and generating warning signals if the difference exceeds predetermined thresholds, using pointer-type measuring instruments and a central device to evaluate and reset signals accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If network frequency is monitored at a single point, then the monitoring system is simple, but islanding detection is slow and unreliable
Solution Approach 1:
The patent divides the power supply network into multiple monitoring sections with measuring instruments distributed at different points. Each section independently measures its local network frequency, and the central device compares these distributed measurements to detect islanding conditions, thereby improving detection reliability through spatial segmentation.
Solution Approach 2:
The patent implements a hierarchical monitoring structure where a central device coordinates multiple distributed measuring instruments. The central device receives frequency data from various sections and performs comprehensive islanding detection by comparing these nested levels of measurement, combining local autonomy with centralized analysis.
2Ease of operation
If frequency threshold values are used for islanding detection, then detection is straightforward, but false alarms occur due to frequency fluctuations
Solution Approach 1:
The patent replaces static frequency threshold comparison with dynamic frequency change rate monitoring. Instead of checking if frequency exceeds a fixed threshold, the system measures the rate of frequency change (df/dt) and compares it against dynamic thresholds, adapting to varying operating conditions and reducing false alarms while maintaining detection simplicity.
3Speed
If warning signals are reset immediately when frequency normalizes, then the system responds quickly, but premature all-clear signals may be generated
Solution Approach 1:
The patent implements a preliminary verification step before resetting warning signals. When frequency returns to normal range, the system first checks whether the frequency change rate also returns to normal levels. Only after both parameters confirm stable operation does the system reset the islanding warning signal, preventing premature clearance while maintaining responsive operation.
Data Source
AI summary
A method and a device are provided for monitoring an electrical power supply network. A temporal frequency change value is determined for at least two sections or for at least two points of the power supply network. The frequency change value indicates the respective temporal frequency change of the network frequency. A conclusion is drawn regarding a possible islanding within the power supply network, and a warning signal which indicates the possible islanding within the power supply network is generated when the difference between the frequency change values, exceeds a predetermined frequency change threshold value.