Rogowski Sensor Temperature Gradient Compensation

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Solution Overview

Problem

Rogowski sensors in Gas Insulated Switchgears (GIS) face precision issues due to temperature gradients, which affect current measurements, leading to inaccuracies in current values.

Innovation Solution

Incorporating multiple digital or analog temperature sensors around the Rogowski coil to measure and compensate for temperature gradients, allowing for accurate temperature compensation and correction of current measurements using computational means.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If Rogowski sensor is used in environment with temperature gradients, then the sensor can operate in practical GIS conditions, but the measurement precision deteriorates due to thermal expansion variations in coil thickness

Engineering Contradiction:
Improveoperational adaptabilityVSAvoidcurrent measurement precision
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The Rogowski coil is divided into multiple segments with independent temperature compensation for each segment. Temperature sensors are placed at different locations along the coil, and each segment's current measurement is compensated based on its local temperature gradient, allowing the sensor to maintain precision across the entire coil structure in practical GIS environments

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the temperature parameter from a single uniform value to a distributed spatial parameter. By measuring temperature at multiple points along the coil and using these temperature parameters to compensate for thermal expansion effects in each segment, the system maintains measurement precision while adapting to real-world temperature gradient conditions

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If temperature compensation is implemented using distributed sensors, then the current measurement accuracy improves to class 0.1, but the device complexity increases due to multiple sensors and computational means

Engineering Contradiction:
Improvecurrent measurement accuracyVSAvoidsensor and computation system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The compensation system is segmented into modular temperature sensor units distributed along the coil, each independently measuring local temperature. This modular approach achieves high accuracy through localized measurements while keeping each sensor unit simple and standardized, reducing overall system complexity compared to a monolithic compensation system

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses the Rogowski coil's own structure and integrated temperature sensors to perform self-compensation. The computational means processes temperature data from sensors already mounted on the coil itself, eliminating the need for external complex compensation apparatus and achieving class 0.1 accuracy through self-service temperature gradient compensation

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

Achieves an accuracy class of 0.1 in current measurement even under significant temperature gradients, ensuring precise energy metering and reducing measurement errors in high-temperature environments.

Implementation Method 1

They are subject to temperature gradients, for example between 5°C and 10 °C, which may affect the value of current measured by the sensor

Methodology Applied
Scientific EffectTemperature gradient: Temperature Gradient

Implementation Method 2

the current induced in the lower part of the coil is different from the current induced in the upper part because of the different thermal expansions

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4390407A1Device for measuring temperature gradients applied to a precision rogowski sensor
Publication Date: 2024.06.26 GENERAL ELECTRIC TECH GMBH
  • EP4390407A1 patent drawingFigure 1~2
  • EP4390407A1 patent drawingFigure 3~4
  • EP4390407A1 patent drawingFigure 5~6

AI summary

The invention relates to a Rogowski sensor (2) comprising a coil on a board (4), for a conductor (30, 40, 50) of a GIS, said sensor comprising at least 2 digital or analog temperature sensors (12, 14, 16, 18).