External Breathing Buffer for Transformer Expansion Tank Oxygen Control
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Solution Overview
Problem
High-voltage systems face challenges in reducing oxygen and moisture intake from the atmosphere, leading to insulation degradation, with existing solutions being costly, ineffective, and lacking reliable monitoring methods.
Innovation Solution
An external breathing buffer system using inert gas is introduced, which connects to the expansion tank and regulates gas exchange based on temperature and pressure, reducing oxygen content and moisture input by exploiting dissolved oxygen consumption during thermal aging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If direct air contact is maintained in the expansion tank, then pressure equalization is simple, but oxygen and moisture intake from the atmosphere increases
Solution Approach 1:
An external breathing buffer filled with inert gas (nitrogen) acts as an intermediary between the expansion tank and the atmosphere. The buffer limits direct air contact while allowing pressure equalization, reducing oxygen and moisture intake into the insulating liquid system.
2Object-affected harmful factors
If separating membranes are used to replace direct air contact, then oxygen exclusion is improved, but costs and device complexity increase
Solution Approach 1:
Instead of using complex separating membranes, the invention uses a simple external breathing buffer filled with inert gas as an intermediary. This approach achieves oxygen exclusion without the complexity and high costs of membrane systems, particularly for retrofit applications.
3Object-affected harmful factors
If nitrogen or vacuum is enclosed in the expansion tank, then oxygen exclusion is improved, but retrofit costs and installation complexity increase
Solution Approach 1:
The system is segmented into two parts: the existing expansion tank and an external breathing buffer. This segmentation allows the buffer to be added separately without modifying the original expansion tank, making retrofit applications simple and cost-effective while achieving oxygen exclusion.
4Object-affected harmful factors
If total removal of oxygen is attempted, then oxygen exclusion is maximized, but technical limitations prevent complete removal
Solution Approach 1:
Instead of attempting complete oxygen removal which is technically impossible, the invention applies partial action by using an inert gas buffer to significantly reduce oxygen and moisture intake. This practical approach achieves sufficient oxygen exclusion to protect the insulating liquid system without requiring unattainable complete removal.
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 solution effectively limits oxygen and moisture intake, extending the service life of high-voltage systems, allowing for online monitoring and maintenance-free operation, while being cost-effective and requiring no downtime for installation.
Implementation Method 1
Load changes as well as fluctuations in the cooling system performance and also the outside temperatures lead to significant temperature changes and thus changes in the volume of the oil filling
Implementation Method 2
an inert gas is fed into the buffer space for faster and greater reduction of the air supply from the atmosphere
Implementation Method 3
the lowering of the oxygen concentration in the oil does not affect the oxygen content in the air space of the expansion tank (detected only in the case of thermal anomalies), since there is rapid replenishment from the atmosphere... with the onset of thermal aging of the insulation system dissolved oxygen is consumed
Data Source
Figure 1
Figure 2~3
AI summary
The method involves determining buffer space volume by lower and upper working temperatures (Tu, To) of an insulating fluid in a high-voltage system i.e. transformer. Gas is delivered from an external buffer space (15) by oil expulsion via a pipe opening (4), where the pipe opening is provided in a casing of inner small tank (3), during exceeding of pre-defined high pressure relative to atmospheric pressure. Air is supplied from the atmosphere into the buffer space via a compensation pipe (8) and by oil expulsion via the pipe opening, when low-pressure falls below the atmospheric pressure. An independent claim is also included for a device for reducing an oxygen content of air in an expansion tank of a high voltage system.