Rogowski Coil Test Signal Injection for GIS Protection Circuits
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Solution Overview
Problem
Current test methods for Rogowski coils in Gas Insulated Switchgears (GIS) fail to effectively simulate high currents, making it impossible to properly test the protection circuit and switches, as they do not represent the actual signals generated by the coil during high current events, and do not adequately test the components upstream of the digitalization stage.
Innovation Solution
A test device that generates a test voltage representative of the secondary signal from a Rogowski coil, transforming it into a voltage between 0.5 V and 10 V, using a capacitive circuit with resistors, and injects this signal into the coil's terminals to test the coil and its associated protection system, allowing for the simulation of high currents and testing of the entire protection circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a test current is directly injected into the digitalization stage to test protection functions, then the protection devices can be tested, but the components upstream of the digitalization stage (wires, integrator, coil) cannot be tested
Solution Approach 1:
The patent uses a test voltage source to generate a test signal that copies the characteristics of the actual secondary voltage signal from the Rogowski coil. This test signal is transformed through transformation means to simulate the voltage output that would occur during real high current events, allowing comprehensive testing of the entire protection circuit without requiring actual high currents.
Solution Approach 2:
The patent introduces transformation means as an intermediary between the test voltage source and the protection system. This intermediary transforms the test voltage into a form that represents the actual coil output, enabling the test signal to properly exercise all components in the signal path including the coil, wires, and integrator.
2Measurement precision
If conventional test methods are used to test protection circuits, then some protection functions can be verified, but the test signals do not represent the actual signals generated by the coil during high current events
Solution Approach 1:
The patent employs transformation means that can adjust electrical parameters (voltage level, impedance) to transform the test voltage into a signal that accurately represents the Rogowski coil's actual output characteristics under different operating conditions, including various default scenarios.
3Reliability
If high currents up to 100 000 A are required to simulate real defaults for testing, then accurate testing of protection responses can be achieved, but portable generators can only generate several tens or hundreds of A
Solution Approach 1:
The patent creates an electrical equivalent of the high current effect by generating a test voltage that produces a secondary signal identical to what the Rogowski coil would generate during high current events. This allows testing the protection circuit's response to high current conditions using only small test currents through portable equipment.
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 test device allows for the comprehensive testing of Rogowski coils and their protection systems, ensuring proper operation by simulating high currents and verifying the functionality of switches and circuit breakers, while protecting the main circuit from common mode signals.
Implementation Method 1
the magnetic field created by the primary current which usually circulates in conductor 2 generates a voltage at the terminals 7, 9 of the coil
Implementation Method 2
transformation means to transform said test voltage into a voltage comprised between 0.5 V and 10V, representative of a secondary signal generated by said Rogowski coil, said transformation means comprising output terminals for connection to conductors
Data Source
AI summary
A test device to test a Rogowski coil and an associated protection device connected to the coil via conductors. The test device includes means to generate at least one test voltage, transformation means to transform the test voltage into a voltage representative of a secondary signal generated by the Rogowski coil, the transformation means including output terminals for connection to conductors, and means to process an output voltage of the coil.