Switchgear Testing via Magnetic Current Measurement
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Solution Overview
Problem
Testing of switchgear in power transmission systems poses safety risks due to the need to manipulate grounding isolators, which is disadvantageous and limits the reliability of measurements such as switching time and resistance determination.
Innovation Solution
A method and system for testing switchgear that maintains the grounding isolators closed during current generation and measurement, allowing for reliable determination of current magnitude and switching times without opening the grounding switches, using devices like current transformers and Rogowski coils to measure currents directly or indirectly through the switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If earthing disconnectors are manipulated for testing the switchgear, then electrical connection for testing can be established, but safety risks increase and measurement reliability is limited
Solution Approach 1:
A current transformer is introduced as an intermediary device to measure the current flowing through the switch under test. The current transformer couples magnetically to the switch current path without requiring direct electrical contact or manipulation of the earthing disconnectors, enabling safe and reliable current measurement while maintaining the earthing disconnectors in their closed position throughout the testing process
2Productivity
If earthing disconnectors are manipulated to establish electrical connection, then testing can be performed, but safety risks increase
Solution Approach 1:
The current transformer serves as a magnetic intermediary that allows testing operations to proceed without manipulating the earthing disconnectors. By measuring current through magnetic coupling rather than direct electrical contact, the system enables full testing capability while eliminating the safety hazards associated with opening or closing earthing disconnectors during testing
Solution Approach 2:
The patent replaces mechanical manipulation of earthing disconnectors with a magnetic field-based measurement system. Instead of physically opening or closing switches to establish test connections, the current transformer uses electromagnetic induction to measure switch current, substituting a safe non-contact method for the hazardous mechanical operation
3Reliability
If current magnitude and switching times are measured without manipulating grounding isolators, then safety is improved, but measurement precision may be compromised
Solution Approach 1:
The current transformer provides high-precision current measurement through magnetic coupling with the switch current path. The transformer's secondary winding accurately reproduces the primary current waveform, enabling precise measurement of both current magnitude and switching time characteristics without any manipulation of the earthing disconnectors, thus maintaining both safety and measurement precision
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 safer and more reliable testing of switchgear by avoiding manipulation of grounding isolators, allowing for precise measurement of switching times and electrical resistance without compromising safety, thereby improving maintenance and defect detection.
Implementation Method 1
a current transformer to measure the current flowing through the switch
Implementation Method 2
or a Rogowski coil to measure the current flowing through the switch
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention provides a method and a system (9) for testing a switching installation (30) for power transmission installations. In this case, the switching installation (30) comprises a switch (2) which selectively connects or disconnects a first side (6) of the switch (2) to a second side (7) of the switch (2), and comprises two grounding disconnectors (10, 11). Each of the two grounding disconnectors (10, 11) is provided in order to selectively connect the first side (6) or the second side (7) to ground (1) or disconnect said first side or said second side from ground (1). In order to test the switching installation (30), a current is generated through the switch (2) and a magnitude of the current through the switch (2) is determined. In this case, the two grounding disconnectors (10, 11) are closed during the process of generating the current and the process of determining the magnitude of the current.