Electric Network Differential Protection With Master Clock Synchronization
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Solution Overview
Problem
Existing methods for differential protection in electrical networks face challenges with accurate time synchronization, particularly in non-deterministic communication networks, leading to uncertainties in current measurements and faults detection.
Innovation Solution
A method utilizing a master clock for precise time synchronization across devices in an electrical network, ensuring that current values measured at different points are timestamped with high accuracy, allowing for reliable comparison and application of Kirchhoff's node law to detect faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS or telegram synchronization is used for time synchronization in differential protection, then devices can be synchronized, but the synchronization accuracy is compromised due to variability in propagation times and complex algorithms required
Solution Approach 1:
A master clock device is introduced as an intermediary time reference that all measuring devices synchronize to. The master clock generates time signals that are distributed to all devices in the network, eliminating the need for complex peer-to-peer synchronization algorithms and GPS-dependent operations. This centralized time reference approach simplifies the synchronization architecture while improving accuracy.
Solution Approach 2:
The system implements a feedback mechanism where the master clock receives time signals from GPS satellites and distributes synchronized time references to all measuring devices. The master clock acts as a feedback hub that consolidates external time references and redistributes them uniformly across the network, ensuring consistent synchronization without requiring each device to independently process GPS signals.
2Reliability
If complex synchronization algorithms are implemented in each device, then time synchronization can be achieved, but the computational complexity and processing requirements increase significantly
Solution Approach 1:
The complex synchronization algorithms are extracted from individual measuring devices and centralized in the master clock device. The master clock performs the computationally intensive time signal processing and algorithm execution, while distributing simplified time references to all other devices. This extraction eliminates the need for complex local synchronization algorithms in each device.
Solution Approach 2:
Each measuring device operates autonomously by simply receiving and using the time signals from the master clock without needing to perform complex synchronization calculations. The devices serve themselves by trusting the centralized time reference, eliminating the need for inter-device algorithmic negotiations and reducing computational burden on each device.
Data Source
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AI summary
A method for monitoring an electrical network (3), in particular a medium-, high- or extra-high-voltage network, for differential protection is provided, wherein the method comprises: measuring, at a first time time determined according to a master clock (7), a first current value (25, 27) by means of a first device (5) at a first location (9) in the network (3) and assigning the first time time; receiving, at a second device (11), the first current value (25, 27) and the assigned first time time; comparing the first current value (25, 27) with a second current value (29, 31) which was measured at a second location (13) in the network (3) and is assigned to the first time time according to the master clock (7).