Partial Discharge Pulse Marker Discrimination for Generator Monitoring
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Solution Overview
Problem
Current partial discharge monitors in power plants cannot accurately determine the origin of partial discharge pulses, leading to false alarms and inefficient analysis, as they detect pulses from all sources within the power plant, including non-threatening locations, which complicates the identification of generator-specific issues.
Innovation Solution
A method and system using marker pulses to differentiate the time of arrival of partial discharge pulses and marker pulses at multiple modules along isophase buses, allowing for the identification of whether a partial discharge pulse originated from the generator by calculating differential values, thereby filtering out non-generator sources and reducing false alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If total detected pulse activity from all plant sources is monitored, then comprehensive coverage of partial discharge detection is achieved, but the ability to identify generator-specific issues is lost due to false alarms from non-generator sources
Solution Approach 1:
A marker pulse is introduced as an intermediary signal to bridge the gap between the generator and the detection system. The marker pulse is injected into the bus at a known location and time, serving as a reference that allows the system to distinguish generator-originated partial discharge pulses from other sources by comparing arrival times and correlation characteristics
Solution Approach 2:
The marker pulse is generated in advance at a predetermined location on the bus before the actual partial discharge detection occurs. This preliminary action establishes a known reference signal that enables subsequent identification and filtering of generator-specific pulses through time-of-flight analysis
2Measurement precision
If manual time-of-flight analysis is performed by experts, then accurate pulse origin determination is possible, but the process is time-consuming and requires specialized personnel
Solution Approach 1:
The system performs automatic time-of-flight analysis using the marker pulse as a reference. The detection system independently calculates arrival time differences and determines pulse origins without requiring expert intervention, thereby maintaining high measurement precision while eliminating the time loss associated with manual analysis
Solution Approach 2:
The marker pulse provides a known reference signal that enables the system to automatically feedback and adjust its analysis algorithms. By comparing the known marker pulse characteristics with detected partial discharge pulses, the system self-calibrates and accurately determines pulse origins through automated correlation and time-difference calculations
3Measurement precision
If six high speed digitizing circuits are used for simultaneous capture at all sites, then analysis quality is significantly improved, but system cost increases substantially
Solution Approach 1:
The marker pulse serves as a mediator that enables accurate analysis with fewer digitizing circuits. By providing a known reference signal, the marker pulse allows the system to achieve high measurement precision using sequential or reduced-number circuits, as the marker pulse compensates for the reduced simultaneous capture capability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate identification of partial discharge pulses originating from the generator, reducing false alarms and providing a more reliable analysis of generator health, enhancing maintenance efficiency and reducing unnecessary downtime.
Implementation Method 1
detecting a partial discharge pulse on the conductor at a first module
Implementation Method 2
generating a marker pulse on the conductor at the first module in response to the detection of the partial discharge pulse
Implementation Method 3
detecting the partial discharge pulse on the conductor at the second module; detecting the marker pulse on the conductor at the second module
Implementation Method 4
determining a differential value corresponding to a difference between a time of arrival of the partial discharge pulse at the second module and a time of arrival of the marker pulse at the second module
Data Source
AI summary
A marker pulse discriminator monitor that enables filtering of partial discharge pulses for monitoring the condition of a generator in a power plant system. The monitor detects partial discharge pulses emanating from the generator and includes a plurality of first modules connected to respective isophase buses adjacent to the generator. Each of the first modules generate a marker pulse in response to a partial discharge pulse. The monitor also includes an analyzer unit connected to the isophase buses adjacent to a step-up transformer. The analyzer unit receives each partial discharge pulse and each marker pulse and determines a differential value corresponding to a difference between a time of arrival of a partial discharge pulse and a time of arrival of a corresponding marker pulse to identify partial discharge pulses originating at the generator and to identify the isophase bus associated with the corresponding partial discharge pulse.