Gas-Insulated Surge Arrester Monitoring via Capacitive Harmonic Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need for condition monitoring of gas insulated surge arresters (GIS) due to the difficulty in obtaining meaningful diagnostic measurements from metal oxide resistor columns inside the GIS surge arrester, as existing monitoring devices are not applicable and redesigning GIS designs for monitoring is costly and affects reliability.
Innovation Solution
A gas insulated surge arrester design that incorporates a capacitive element, such as a capacitive tap or metal field probe, to extract the capacitive component of the leakage current, enabling the use of existing monitoring devices for condition monitoring by compensating for system voltage harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a field probe is mounted at the base of the surge arrester to perform third harmonic analysis, then meaningful diagnostic measurement is enabled, but this approach is not applicable for GIS surge arresters since they are enclosed in metallic encapsulation
Solution Approach 1:
A capacitive coupling device is introduced as an intermediary element that can be mounted on the external housing of the GIS surge arrester. This device couples capacitively to the metal oxide resistor column through the housing wall, enabling third harmonic analysis without requiring direct access to the resistor column or opening the metallic encapsulation. The intermediary device transfers the diagnostic signal from the enclosed component to an external measurement point.
2Device complexity
If traditional surge counters with total leakage current measurement are used for GIS surge arresters, then monitoring is simplified, but meaningful diagnostic information about the condition of the surge arrester is not obtained
Solution Approach 1:
The monitoring function is segmented into two distinct measurement components: total leakage current measurement (for basic monitoring) and capacitive third harmonic current measurement (for diagnostic analysis). The capacitive coupling device specifically extracts the third harmonic component, which when processed through third harmonic analysis, provides diagnostic information about the condition of the metal oxide resistor column. This segmentation allows both simple monitoring and detailed diagnostics to coexist.
3Reliability
If GIS surge arresters are designed with enhanced monitoring capabilities, then condition monitoring is enabled, but cost increases and reliability may be affected
Solution Approach 1:
The capacitive coupling device serves as an external intermediary that attaches to the existing housing without requiring modification of the metal oxide resistor column or the internal GIS structure. This approach enables monitoring capability addition while minimizing manufacturing complexity and cost, as the device can be mounted on the external surface and couples through the existing housing wall.
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 accurate condition monitoring of GIS surge arresters using existing monitoring systems, minimizing cost and maintaining reliability by extracting the required measurement signal from within the metal clad housing.
Implementation Method 1
a capacitive element, such as a capacitive tap or metal field probe, to extract the capacitive component of the leakage current
Data Source
Figure 1
Figure 2~5
AI summary
A gas insulated surge arrester (1a, 1b, 1c) is disclosed, comprising a metal clad housing (3) within which a block stack (4) is arranged. The block stack (4) comprises at least one metal-oxide resistor column (2) and the gas insulated surge arrester (1a, 1b, 1c) is characterized by a capacitive element (9a, 9b, 9c) arranged to obtain an electric field measurement of the gas insulated surge arrester (1a, 1b, 1c); and by a bushing (10a, 10b, 10c) arranged through the metal clad housing (3) and arranged to the provide a capacitive third-order harmonic current measurement to an input of a surge arrester monitoring device (7). A monitoring system (100) is also provided, comprising a gas insulated surge arrester (1a, 1b, 1c) connected to a surge arrester monitoring device (7).