GIS Electronic Instrument Transformer Test System for Transient Interference

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Solution Overview

Problem

Current electromagnetic compatibility test methods for electronic instrument transformers in smart grids do not adequately simulate real-world conditions, particularly for high voltage levels, leading to insufficient protection against electromagnetic interference and increased fault rates.

Innovation Solution

A GIS electronic instrument transformer test system based on opening-closing small capacity current of an isolating switch, which includes a power supply casing, a load casing, and a GIS pipeline with adjustable length, simulating onsite electromagnetic interference by using capacitive voltage dividers, primary transient test systems, and secondary converters to record and analyze voltage and current waveforms during switch operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If current electromagnetic compatibility test methods are used, then test standards can be followed, but the test conditions do not adequately simulate real-world high voltage environments leading to insufficient protection performance

Engineering Contradiction:
Improveelectromagnetic protection performanceVSAvoidsimulation of real-world conditions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the test parameters by using actual high voltage switch operation conditions (opening and closing of isolating switches) instead of standard test waveforms. This involves using real transient voltage and current parameters generated during switch operations to create test conditions that accurately reflect real-world electromagnetic interference environments.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary calibration by measuring actual transient voltage and current parameters during switch operations before using them for testing electronic instrument transformers. This preliminary measurement and characterization of real interference conditions allows the subsequent tests to be based on authentic operational data rather than theoretical waveforms.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If standard electromagnetic compatibility tests are conducted, then existing standards can be met, but the tests fail to detect electromagnetic interference issues that occur in actual high voltage substation environments

Engineering Contradiction:
Improvedetection of electromagnetic interferenceVSAvoidtest system configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary measurement system that captures actual transient voltage and current parameters during switch operations. This intermediary system acts as a bridge between the complex real-world interference environment and the electronic instrument transformer under test, translating real operational conditions into measurable test parameters without requiring direct exposure to full-scale high voltage interference.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a simplified copy of real electromagnetic interference conditions by measuring and reproducing transient voltage and current waveforms from actual switch operations. Instead of directly applying complex real-world interference, the system captures representative waveform characteristics and uses these copies for controlled testing, maintaining measurement precision while reducing test system complexity.

Inventive Principle:
Principle #26Copying

3Measurement precision

If electronic instrument transformers are placed closer to primary circuits to improve monitoring accuracy, then measurement precision improves, but vulnerability to electromagnetic interference increases

Engineering Contradiction:
Improvemonitoring accuracyVSAvoidelectromagnetic interference vulnerability
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful electromagnetic interference environment into a beneficial testing opportunity. By using actual switch operation transients as test stimuli, the harmful interference conditions become the basis for validating and improving electromagnetic protection performance. The same environment that causes vulnerability is used to verify and enhance protection capabilities.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements feedback by measuring actual transient parameters during switch operations and using these measurements to adjust and optimize test conditions. The system continuously refines its understanding of real interference characteristics and uses this feedback to improve the accuracy and effectiveness of electromagnetic compatibility testing for electronic instrument transformers.

Inventive Principle:
Principle #23Feedback

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 system effectively enhances the electromagnetic protection performance of electronic instrument transformers by simulating strong interference conditions, reducing fault rates and improving reliability in high voltage environments.

Implementation Method 1

a capacitive voltage divider used for protecting a power supply, which are connected in parallel, said capacitive voltage divider is used for reducing a resonance effect caused by higher power supply impedance

Methodology Applied
Scientific EffectCapacitive voltage division: Capacitance

Implementation Method 2

a high voltage test transformer and a capacitive voltage divider used for protecting a power supply

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

under the conditions of switch operation and system short circuit, the electronic instrument transformers are more vulnerable to interference by direct conduction and electromagnetic field coupling

Methodology Applied
Scientific EffectElectromagnetic field coupling: Electromagnetic Induction

Implementation Method 4

a first calibration primary transient test system, a first to-be-tested electronic instrument transformer, a second to-be-tested electronic voltage transformer and a second calibration primary transient voltage test system are arranged between the first isolating switch and the load casing

Methodology Applied
Scientific EffectElectromagnetic sensing: Electromagnetic Induction

Data Source

PatentEP3045930B1Testing system of GIS electronic mutual inductor and method therefor
Publication Date: 2018.05.16 STATE GRID CORPORATION OF CHINA
  • EP3045930B1 patent drawingFigure 1~2
  • EP3045930B1 patent drawingFigure 3
  • EP3045930B1 patent drawingFigure 4~5

AI summary

A GIS electronic instrument transformer test system based on opening-closing small capacity current of an isolating switch, in the GIS electronic instrument transformer test system that includes a high voltage test transformer connected to a BSG casing, a capacitive voltage divider, a load capacitor connected to the other BSG casing, an isolating switch between the two casings, a calibration primary transient test system and an to-be-tested electronic instrument transformer, wherein one end of a secondary converter is connected with the to-be-tested electronic instrument transformer, the other end of the secondary converter is connected with a merging unit, and the other end of the merging unit is connected with a fault recorder. When the isolating switch is opened and closed, a voltage value and a current valve of a high voltage bus are tested to compare with the output of the to-be-tested electronic instrument transformer. By means of the test system, electromagnetic environments of 110KV, 220KV and 500KV voltage levels in power transmission and outage processes can be simulated to load processes of opening-closing empty conducting wires and small capacity current of the isolating switch onsite, in order to generate similar onsite transient strong interference to check the electromagnetic protection performance of the electronic instrument transformer under the condition.