DC Microgrid Fault Location Using Single-Ended Local Measurements
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Solution Overview
Problem
Existing fault detection and location methods for DC microgrids are slow, system-dependent, and require communication, making them inadequate for fast and reliable protection in DC microgrids.
Innovation Solution
A deterministic closed-form mathematical formulation using time domain data sampled at high frequency, which allows for fast fault detection and location without relying on fault resistance, system topology, or communication, using only single-ended local measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If communication-based fault detection methods are used, then measurement precision can be improved, but response time increases and reliability decreases
Solution Approach 1:
The patent extracts and eliminates the communication dependency from the fault detection system. By using only local single-ended measurements at one bus, the method removes the time-consuming communication环节 between multiple measurement points, achieving fast fault location without sacrificing precision through the use of specialized mathematical formulations that work with limited local data
Solution Approach 2:
The patent segments the fault detection problem into local measurable quantities (voltage and current at one bus) versus global system parameters. By formulating the fault location algorithm to depend only on locally available measurements and known line parameters, the method achieves both speed (through local processing) and precision (through careful mathematical design)
2Measurement precision
If system-dependent fault detection methods are used, then measurement precision can be improved, but device complexity and adaptability worsen
Solution Approach 1:
The patent creates a universal fault detection method that works across different DC microgrid topologies (radial, meshed, multi-terminal) without requiring system-specific customization. The single-ended measurement approach combined with the proposed mathematical formulation provides a one-size-fits-all solution that maintains high accuracy across diverse system configurations, eliminating the need for complex system-dependent algorithms
3Measurement precision
If communication-based fault detection methods are used, then measurement precision can be improved, but reliability decreases due to communication delays and uncertainties
Solution Approach 1:
The patent extracts and eliminates communication from the fault detection chain, using only local measurements processed through a deterministic mathematical algorithm. This removal of communication eliminates the source of delays and uncertainties, providing reliable and repeatable fault location results that are independent of communication system performance
Solution Approach 2:
The patent uses pre-known line parameters (resistance and inductance per unit length) and pre-established mathematical relationships to enable immediate fault location calculation from local measurements. This preliminary preparation of system data and algorithm formulation allows for reliable, real-time fault detection without requiring real-time data exchange or complex real-time computations
Data Source
AI summary
Systems and methods of determining fault location on a DC microgrid feeder need to be extremely fast to protect the circuit breaker and converter-source components. This disclosure develops a seminal theoretical foundation for fast fault location on a DC feeder that uses only single-ended local measurements in time domain. The theory provides a closed-form deterministic solution for fault location, making the resulting fault location method agnostic to system-topology and immune to fault resistance. The theory is developed with ideal DC voltage sources and is extended to practical converter-sources. The performance of the resulting method is demonstrated by simulating a DC feeder with converters connected at both ends, modeled in PSCAD (power systems computer-aided design).