High Voltage Bushing Connection Restoration via Machining and Conductive Plating
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Solution Overview
Problem
Current methods for maintaining and replacing high voltage bushings (HVBs) in gas-cooled generators are insufficient in preventing early failures, as they often result in subsequent failures shortly after maintenance or replacement, often due to issues like leaking asphalt and inadequate contact surface engagement between the tubular lead and the lower stud connector.
Innovation Solution
A method involving disassembly, inspection, and restoration of the HVB connection by applying conductive material, machining to precise diameters, and silver plating, along with contact surface checks using a bluing agent to ensure proper engagement and surface area contact, is employed to maintain and repair HVB connections, addressing the inefficiencies in existing practices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If current maintenance and replacement methods are used for HVB connections, then the process is simple and quick, but the service life is reduced due to early failures
Solution Approach 1:
The patent applies preliminary action by inspecting and restoring contact surfaces before reassembly. The method includes disassembling the HVB connection, inspecting contact surfaces for degradation, machining surfaces to remove contaminants and irregularities, and applying conductive material to ensure proper electrical contact. This preliminary restoration prevents early failures and extends service life.
Solution Approach 2:
The patent applies parameter changes by modifying the physical and electrical parameters of contact surfaces. The machining process changes the surface geometry and roughness, while the application of conductive material changes the electrical conductivity parameter. These parameter changes ensure optimal electrical contact and reduce resistance, preventing overheating and failure.
2Reliability
If contact surfaces are not properly restored, then the maintenance process is faster, but electrical resistance increases causing overheating and failure
Solution Approach 1:
The patent performs preliminary inspection and restoration of contact surfaces before reassembly. This includes disassembling the connection, inspecting surfaces for contaminants and irregularities, machining surfaces to proper specifications, and applying conductive material. This preliminary action ensures reliable electrical contact and prevents future failures.
Solution Approach 2:
The patent replaces inadequate mechanical contact with optimized electrical contact. By machining surfaces to precise tolerances and applying conductive material, the method substitutes poor mechanical mating with controlled electrical contact, ensuring reliable current flow and reducing resistance-related failures.
3Reliability
If asphalt is allowed to leak from HVB, then the HVB structure remains intact, but electrical discharge occurs causing degradation
Solution Approach 1:
The patent performs preliminary inspection and restoration during maintenance outages to detect and address asphalt leakage issues before they cause electrical discharge. By inspecting contact surfaces and restoring proper connections, the method prevents the conditions that lead to asphalt leakage and subsequent electrical discharge.
Solution Approach 2:
The patent applies preliminary anti-action by preventing the conditions that lead to asphalt leakage. Through proper contact surface restoration and securing of HVB connections, the method prevents the mechanical stress and electrical arcing that would otherwise cause seal degradation and asphalt leakage.
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 method significantly extends the service life of HVBs by ensuring proper contact surface engagement and reducing electrical resistance, thereby minimizing the likelihood of premature failure during maintenance and replacement processes.
Implementation Method 1
contact surface checks using a bluing agent to ensure proper engagement and surface area contact
Implementation Method 2
applying conductive material to at least one of a mating portion of a tubular lead and a mating portion of a high voltage bushing
Implementation Method 3
silver plating, along with contact surface checks
Data Source
AI summary
A method of maintaining a high voltage bushing can comprise inspecting a high voltage bushing connection, the high voltage bushing connection comprising a tubular lead, a lower stud connector, and the high voltage bushing. A method of maintaining a high voltage bushing can also comprise restoring the high voltage bushing connection, which can further comprise applying conductive material to at least one of a mating portion of a tubular lead and a mating portion of a high voltage bushing, machining an outside diameter of at least one of the mating portion or the tubular lead and the mating portion of the high voltage bushing to a predetermined outer diameter, and machining a mating portion of a lower stud connector to a predetermined inner diameter. A high voltage bushing connection can comprise a restored mating portion of a tubular connector and a restored lower stud connector.