Transformer Oil Drying Control to Prevent Insulation Overdrying

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Power transformers fail prematurely due to moisture accumulation in cellulose paper insulation, leading to insulation degradation and transformer failure, with existing methods either failing to effectively remove moisture or causing overdrying issues that compromise the transformer's ability to withstand short circuit events.

Innovation Solution

A system for continuously removing moisture from power transformers while maintaining optimal dryness levels, using a combination of sensors, a processor, and an overdry prevention bypass valve to manage moisture levels, with zeolite granules in drying cylinders to capture moisture from the oil, ensuring the transformer operates within a safe moisture range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If moisture removal is intensified to extend transformer life, then insulation aging is slowed, but overdrying occurs causing mechanical loosening during short circuit events

Engineering Contradiction:

Improvetransformer lifeVSAvoidwinding mechanical strength

Core Design Contradiction:

Duration of action of stationary objectVSStrength

Solution Approach 1:

The system continuously monitors moisture content in the cellulose insulation and adjusts the drying process accordingly. Sensors detect moisture levels and provide feedback to the control system, which modulates the drying intensity to prevent both excessive moisture (causing aging) and overdrying (causing mechanical loosening). This closed-loop control enables precise maintenance of moisture content within the optimal range.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically changes operating parameters during the drying process, including temperature, vacuum level, and gas flow rate. By adjusting these parameters in real-time based on moisture content measurements, the system can intensify drying when moisture is high and reduce intensity when approaching the target moisture level, thereby preventing overdrying while maximizing moisture removal efficiency.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If continuous moisture monitoring and control is implemented, then optimal dryness is maintained, but system complexity increases

Engineering Contradiction:

Improvemoisture level controlVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system incorporates automatic self-regulation through integrated sensors and control logic that autonomously monitor moisture content and adjust drying parameters without requiring constant manual intervention. The control system automatically determines when to intensify or reduce drying based on real-time moisture measurements, enabling the system to self-manage the moisture removal process while maintaining reliability.

Inventive Principle:

Principle #25Self-service

3Duration of action of stationary object

If aggressive drying is applied to remove moisture from insulation, then aging is reduced, but mechanical properties of windings deteriorate

Engineering Contradiction:

Improveinsulation service lifeVSAvoidinsulation mechanical stability

Core Design Contradiction:

Duration of action of stationary objectVSStability of the object's composition

Solution Approach 1:

The drying process transitions from static to dynamic control, where drying intensity continuously adapts based on moisture content measurements. The system employs variable intensity drying phases: intensive drying when moisture is high, and gentle drying when approaching target levels. This dynamic approach maximizes moisture removal while preserving mechanical integrity by avoiding excessive drying stress on the insulation and windings.

Inventive Principle:

Principle #15Dynamics

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

The system effectively extends the life of power transformers by slowing down aging effects, maintaining reliability, and reducing the risk of failure, while preventing overdrying that could lead to mechanical issues during short circuit events.

Implementation Method 1

zeolite granules in drying cylinders to capture moisture from the oil

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

any increase in operating temperature will drive moisture out of the cellulose paper insulation

Methodology Applied

Scientific EffectThermal diffusion: Diffusion

Implementation Method 3

This free moisture will either dissolve in the oil if the oil is 'dry' enough, or will 'rain down,' in an energized field

Methodology Applied

Scientific EffectPhase change: Phase Change

Data Source

PatentUS11801455B2Systems and methods for removing moisture from a power transformer

Publication Date: 2023.10.31 THE ARDRY GRP

AI summary

The disclosure includes embodiments of systems and methods for removing moisture from an electric power transformer. According to an embodiment, a moisture removal system includes a pump to move oil from the transformer into the system; one or more incoming oil moisture and temperature sensors to detect a first moisture level and temperature of oil; a processor to receive the moisture and temperature and determine an estimated paper moisture value of the insulation of the transformer, and compare the estimate to a target paper moisture value; and an overdry prevention bypass valve positioned in a first position to divert oil without drying when the estimated paper moisture value is equal to or less than the target value, and in a second position to channel oil through one or more drying cylinders when the estimated paper moisture value exceeds the target value.