Gas Density Relay Self-Calibration Using Temperature Compensation

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Solution Overview

Problem

Current gas density relays in SF6 electrical equipment require regular manual calibration, which is costly, risky, and disrupts power operations, while existing online monitoring systems are prone to electromagnetic interference and lack effective self-calibration capabilities.

Innovation Solution

A gas density relay with an integrated online self-calibration function, comprising a gas density relay body, sensor, temperature regulation, and intelligent control unit, allowing for contact signal sampling and calibration without additional equipment, ensuring safe and reliable operation by regulating temperature and pressure to perform self-calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual calibration of gas density relays is performed regularly, then measurement precision is maintained, but loss of time and productivity decrease due to operational disruption

Engineering Contradiction:
Improvegas density relay calibration accuracyVSAvoidpower operation disruption time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The gas density relay performs self-calibration automatically by utilizing the existing temperature and pressure sensors already present in the system. The calibration process is initiated and executed by the relay itself without requiring external calibration equipment or manual intervention, thereby maintaining measurement precision while eliminating operational disruption and time loss associated with manual calibration procedures

Inventive Principle:
Principle #25Self-service

2Ease of operation

If additional calibration equipment is installed for self-calibration, then ease of operation improves, but device complexity increases

Engineering Contradiction:
Improvecalibration operation convenienceVSAvoidrelay structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The temperature and pressure sensors originally designed for monitoring gas density are dual-used for calibration purposes. The existing sensor data serves both operational monitoring and calibration functions, eliminating the need for additional dedicated calibration equipment while maintaining ease of operation through automatic self-calibration capabilities

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The relay utilizes its own internal sensors and processing units to perform calibration, requiring no external calibration equipment. The system self-manages the calibration process by comparing sensor readings against predefined reference values and automatically adjusting calibration parameters, thereby improving operational convenience without increasing device complexity

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If temperature regulation mechanism is added for calibration, then manufacturing precision improves, but ease of manufacture decreases

Engineering Contradiction:
Improvecalibration accuracyVSAvoidrelay assembly difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The temperature sensor originally intended for gas density monitoring is repurposed to provide temperature data for calibration operations. This multi-functional use of existing components achieves the necessary calibration accuracy without requiring separate temperature regulation mechanisms, thereby maintaining ease of manufacture while improving manufacturing precision

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The calibration process leverages the existing temperature and pressure sensor data already collected during normal operation. By processing this existing data through the relay's control unit, the system achieves accurate calibration without requiring additional temperature regulation hardware, thus maintaining manufacturing simplicity while improving calibration precision

Inventive Principle:
Principle #25Self-service

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

Enables reliable and cost-effective self-calibration of gas density relays, reducing maintenance needs and ensuring safe operation of electrical equipment by integrating temperature and pressure regulation within the relay, thus improving power grid reliability and reducing operational costs.

Implementation Method 1

Temperature rise and fall of a temperature compensation element of the gas density relay is regulated through the temperature regulating mechanism

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The pressure regulator is controlled through the intelligent control unit, so that pressure rise and fall enable contact action of the gas density relay body

Methodology Applied
Scientific EffectPressure regulation: Pressure Increase

Data Source

PatentEP4027152B1Method for modifying a gas density relay with online self-calibration function and calibration method therefof
Publication Date: 2026.01.28 SHANGHAI ROYE ELECTRICAL CO LTD
  • EP4027152B1 patent drawingFigure 1~2
  • EP4027152B1 patent drawingFigure 3~4
  • EP4027152B1 patent drawingFigure 5~7

AI summary

The modification method for the gas density relay, the gas density relay with the online self-check function and the check method thereof provided by this application are used for high-voltage and medium-voltage electrical equipment, including a gas density relay body, a gas density detection sensor, a temperature regulating mechanism, an online check contact signal sampling unit and an intelligent control unit. Regulate temperature rise and fall of the temperature compensation element of the gas density relay body through the temperature regulating mechanism, which leads to a contact action of the gas density relay body, the contact action is transferred to the intelligent control unit through the online check contact signal sampling unit, and the intelligent control unit detects the operating value and/or return value of the contact signal of the gas density relay body based on the density value at the time of contact action. The gas density relay check can be completed without maintainer at the site, so as to realize free maintenance, greatly improve the reliability of power grid, increase work efficiency and reduce the cost.