Multi-Criteria Protection Device for Electrical Network Error Detection
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Solution Overview
Problem
Existing protection devices in electrical energy supply networks rely exclusively on impedance change rate for error type identification, leading to incorrect disconnections or missed disconnections, especially under varying network conditions and deregulated power transmission scenarios, requiring more reliable and selective error detection methods.
Innovation Solution
A method and protection device that evaluate measured values using multiple protection criteria in parallel, incorporating different measured values and algorithms, to generate an error signal that considers all available results for each potential loop, enhancing reliability and adaptability to different network situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single protection criterion (impedance change rate) is used for error type identification, then the protection device operates with simple evaluation logic, but the reliability of error detection deteriorates due to incorrect disconnections or missed disconnections under varying network conditions
Solution Approach 1:
The evaluation logic is segmented into multiple independent protection criteria (impedance change rate criterion, current ratio criterion, voltage criterion) that operate in parallel. Each criterion independently evaluates the error type using different measured values and algorithms, and the final error type identification is determined by combining the results of all criteria. This segmentation allows the system to maintain high reliability through multiple evaluation paths while keeping each individual criterion relatively simple.
2Reliability
If multiple protection criteria are evaluated in parallel, then the reliability of error type detection improves by considering all available results, but the device complexity increases due to multiple algorithms and measured values
Solution Approach 1:
The protection device dynamically adapts its evaluation process by selectively activating different protection criteria based on the current operating conditions and available measured values. The system can adjust which criteria are applied in parallel depending on the network situation, making the complexity adaptive rather than static. This allows the device to maintain high reliability when needed while reducing complexity under normal operating conditions.
3Adaptability or versatility
If multiple protection criteria are used, then the adaptability to different network situations improves, but the computational requirements and processing time increase
Solution Approach 1:
The protection device performs preliminary actions by pre-configuring multiple protection criteria and their associated algorithms before actual error detection is needed. The system prepares the evaluation framework in advance, so that when an error occurs, the multiple criteria can be rapidly evaluated in parallel without requiring complex real-time decision-making about which criteria to use. This preliminary preparation reduces the processing time during actual error detection while maintaining adaptability to different network situations.
Data Source
AI summary
A method for generating an error signal indicating an error type of an error in a multi-phase electrical energy supply network. Measured values describe a current operating state of the network. The measured values are transmitted to a protection device. An evaluating device evaluates every possible loop of the network that can be affected with respect to the recognition of the error type of an error, by using the measured values. In order to be able to more reliably recognize the error type even under different network conditions, the measured values and/or values derived from the measured values are evaluated using at least two different protection criteria, for every possible loop. Each of the protection criteria is suitable for indicating an error type of an error present in the evaluated loop, and the error signal is generated in consideration of all available evaluation results of the protection criteria.