Subscriber Line Module Leakage Current Isolation
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Solution Overview
Problem
Current methods for conducting DC set tests on subscriber line assemblies are hindered by interference from leakage currents, leading to erroneous results and require additional hardware and personnel, increasing space and economic costs.
Innovation Solution
Applying a predeterminable voltage to the subscriber line's two cores, connecting test impedances between the wires, and using existing switches and resistors on the module to determine current flow, allowing for internal measurement and subtraction of leakage currents to isolate the actual current for testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external measuring devices are used to conduct DC set tests on subscriber line assemblies, then measurement capability is provided, but interference from leakage currents causes erroneous results
Solution Approach 1:
The patent extracts the harmful leakage current component from the total measured current by applying Kirchhoff's current law. The measuring device measures the total current, and the leakage current is separately determined through additional measurements with test impedances connected to ground. By subtracting the leakage current from the total current, the harmful interference is removed to obtain the accurate current flow through the subscriber line assembly.
Solution Approach 2:
The patent introduces test impedances as intermediary elements connected between the subscriber line wires and ground. These test impedances serve as mediators to enable the determination of leakage current without directly connecting measurement equipment to the subscriber line in a way that would cause interference. The test impedances allow indirect measurement of leakage current while isolating the harmful effects from the main measurement.
2Measurement precision
If test impedance and relays are added to the subscriber line module to eliminate interference, then measurement accuracy improves, but hardware complexity and space requirements increase
Solution Approach 1:
The patent makes the measuring device multi-functional by enabling it to perform both the primary DC set test and the leakage current determination. The same measuring device that measures total current is also used to measure current through test impedances for determining leakage current. This eliminates the need for separate dedicated leakage current measurement equipment, reducing hardware complexity while maintaining test accuracy.
Solution Approach 2:
The patent combines the functionality of multiple measurement operations into a single integrated measurement process. Instead of using separate devices for total current measurement and leakage current measurement, the patent merges these functions into one measuring device that sequentially performs both measurements. This consolidation reduces the number of hardware components needed while achieving accurate interference-free testing.
3Reliability
If conventional test methods with test impedance are used, then interference is eliminated, but additional hardware and economic effort are required
Solution Approach 1:
The patent enables the subscriber line assembly to perform self-diagnosis by having the module itself conduct the DC set test and determine leakage current using its own integrated measuring device. The module uses its built-in resources (measuring device, test impedances) to test its own functionality without requiring external specialized equipment. This self-service approach reduces economic effort while maintaining reliable test results.
Solution Approach 2:
The patent recovers and reuses existing components within the subscriber line module for testing purposes. The measuring device and test impedances that are already part of the module's standard configuration are reused for DC set testing instead of requiring additional separate hardware. This approach discards the need for extra economic investment in specialized test equipment while maintaining test reliability.
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 method eliminates the need for external measuring equipment and additional hardware, reducing costs and ensuring accurate testing of subscriber line assemblies by isolating interference and determining correct functioning based on precise current measurements.
Implementation Method 1
a predeterminable voltage is applied to the two cores of the subscriber line
Implementation Method 2
Information representing the current flowing in the subscriber line is determined
Implementation Method 3
At least a first test impedance is then connected between ground and the first wire of the subscriber line
Data Source
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AI summary
The invention relates to a method and to an arrangement for performing a set test on a subscriber connection component (SLM) by means of a subscriber connection line (TAL) comprising two wires (a,b) and which is associated with the subscriber connection components (SLM). According to the inventive method, interference of, for example, leakage currents (ILeakage- a, ILeakage-b) on a subscriber connection line (TAL) which is associated with the subscriber connection component (SLM) are taken into account. A predetermined voltage (Ux) is adjusted on the subscriber connection line (TAL) and the current on the subscriber connection line (TAL) is determined (IMeasure-a-1, IMeasure-b-1). Subsequently, at least one test impedance (Ra, Rb) is connected to the subscriber connection line (TAL) and re-determines the current (IMeasure-a-2, IMeasure-b-2) flowing over the subscriber connection line (TAL). Finally, the subscriber connection component (SLM) can be tested as to whether it functions correctly with the help of the measuring data (IMeasure-a-1, IMeasure-b-1, IMeasure-a-2, IMeasure-b-2).