Grid Faulted Phase Identification Using Two-Plane Sequence Signatures
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Solution Overview
Problem
Existing power grid systems struggle to accurately identify fault types and faulted phases, especially in grids with renewable energy sources, due to limitations in fault current detection and control strategies.
Innovation Solution
A system and method using a relay and controller to monitor power grid lines, generate sequence voltages and currents, and determine first and second plane sequence signatures to identify fault types and faulted phases, even in weak infeed conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fault detection methods are used in power grids with renewable energy sources, then the system structure remains simple, but the fault type and faulted phase identification accuracy deteriorates due to weak infeed conditions
Solution Approach 1:
The patent segments the fault analysis into two distinct planes: the first plane uses positive and negative sequence components, while the second plane uses zero and negative sequence components. This segmentation allows accurate fault identification in weak infeed conditions by analyzing fault characteristics from multiple independent planes, resolving the contradiction between maintaining simple system structure and achieving high identification accuracy.
Solution Approach 2:
The patent transitions from conventional single-plane fault analysis to two-plane sequence analysis, adding a dimensional aspect to fault detection. By determining fault types and phases in two different sequence planes, the system achieves superior accuracy in identifying faults under weak infeed conditions without requiring additional hardware, effectively resolving the measurement precision versus device complexity contradiction.
2Measurement precision
If additional hardware or communication systems are added to improve fault detection accuracy, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent makes the existing relay device perform multiple functions: it not only detects faults but also determines fault types and faulted phases by analyzing two-plane sequence characteristics. This multi-functionality allows the single relay device to achieve high detection accuracy without requiring additional specialized hardware or communication systems, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The relay device uses its own existing measurement capabilities to perform comprehensive fault analysis. By utilizing the sequence components already available from the power system and processing them through two-plane analysis, the relay serves itself to achieve accurate fault identification without external assistance or additional hardware, eliminating the need for extra devices while maintaining high precision.
3Measurement precision
If conventional single-plane sequence analysis is used, then the system operation remains fast, but measurement precision deteriorates in weak infeed conditions
Solution Approach 1:
The patent performs preliminary determination of sequence components (positive, negative, and zero sequences) that can be used for both the first and second plane analyses. By pre-calculating these sequence components from the measured voltages and currents, the system enables rapid two-plane fault analysis without significant time penalty, resolving the contradiction between measurement precision and time loss in fault identification.
Data Source
AI summary
A system for detecting a fault type and faulted phase in a power grid includes a controller and a relay. The relay is configured to monitor a line of the power grid and generate a monitoring signal. The controller may be configured to determine, in response to the monitoring signal received from the relay, sequence voltages and sequence currents in the line. The controller may further determine, in response to the sequence voltages and sequence currents, an absence or a presence of a weak-infeed condition in the line. The controller may further determine, in response to the monitoring signal and the absence or the presence of the weak-infeed condition, a first plane sequence signature and a second plane sequence signature. The controller may further determine a fault type and faulted phase in the power grid in response to the first plane sequence signature and the second plane sequence signature.