Ground Connection Monitoring Circuit for Quantitative Resistance Sensing
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Solution Overview
Problem
Existing insulation monitoring devices for ungrounded power supply systems struggle to accurately determine the ground resistance independently of the measuring voltage, leading to unreliable ground connection monitoring and potential false alarms due to binary decision-making.
Innovation Solution
An active loop measurement device with an independent excitation voltage source is used to quantify ground resistance between the insulation monitoring device and the ground terminal, allowing for continuous monitoring and adaptive alarm thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an independent excitation voltage source is added to enable quantitative ground resistance measurement, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The electric measuring arrangement is integrated within the insulation monitoring device, with the independent excitation voltage source and measuring components nested inside the existing device structure. This allows quantitative ground resistance measurement capability to be embedded without requiring a completely separate external system, thereby improving measurement precision while limiting the increase in overall device complexity.
Solution Approach 2:
An independent excitation voltage source is introduced as an intermediary component between the ground-connection clamp and the ground terminal. This intermediary provides a controlled test signal that enables precise measurement of ground resistance by creating a known voltage condition, allowing accurate measurement without directly modifying the existing insulation monitoring functionality.
2Reliability
If continuous quantitative monitoring of ground resistance is implemented, then reliability is improved, but use of energy increases
Solution Approach 1:
The independent excitation voltage source operates by applying test voltages periodically rather than continuously. The measuring arrangement applies test voltages at specific intervals to measure ground resistance, allowing continuous monitoring capability while reducing energy consumption by keeping the excitation source inactive between measurement cycles.
Solution Approach 2:
The measuring arrangement dynamically adjusts its operation based on monitoring needs. The independent excitation voltage source can be activated or deactivated dynamically, and the measurement frequency can be adjusted based on system conditions, enabling reliable monitoring while optimizing energy usage according to actual requirements.
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 reliable and quantitative assessment of ground connection quality, reducing interference susceptibility and enabling customized alarm settings, thus ensuring accurate insulation monitoring.
Implementation Method 1
an independent excitation voltage source (UgEKE) for quantitatively determining a ground resistance (REKE) of the ground connection
Implementation Method 2
a series connection comprising the excitation voltage source for superimposing an excitation voltage UgEKE, a loop measuring resistance RmEKE, a loop coupling resistance RaEKE
Data Source
AI summary
The invention relates an electric measuring arrangement (10) and to a measuring method both for monitoring a ground connection for an insulation monitoring device (4), which is connected to at least one active conductor (L1, L2) of an ungrounded power supply system (2) and a ground terminal (PE) of an electric installation (3), with an active loop measurement device (20), which is connectable between a ground-connection clamp (E) of the insulation monitoring device (4) and the ground terminal (PE) and has an independent excitation voltage source (UgEKE) for quantitatively determining a ground resistance (REKE) of the ground connection (6) between the insulation monitoring device (4) and the ground terminal (PE).Furthermore, the invention relates to an insulation monitoring device (30) having an electric measuring arrangement (10) according to the invention.