Isolation Transformer for RCD Testing Without Power Interruption
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Solution Overview
Problem
Existing methods for testing residual current devices (RCDs) require disconnecting sensitive loads, leading to refusal of power disruptions and non-validation of installations, as they fail to ensure continuous energy supply during testing.
Innovation Solution
A device with an isolation transformer and phase-selective interface maintains power supply continuity by isolating and replacing the RCD cut-off device, allowing zero-sequence current measurement and tripping time assessment without apparent power loss, while also measuring insulation faults using a secondary power source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the RCD testing method requires disconnection of downstream loads, then the RCD can be properly tested for tripping function, but the sensitive load experiences power interruption and installation validation is refused
Solution Approach 1:
The patent introduces a double-pole switching device as an intermediary component between the RCD and the sensitive load. This switching device can be independently controlled to disconnect only for testing purposes while maintaining the load connection through alternative pathways or backup power sources, thus mediating between testing requirements and continuous power supply needs
Solution Approach 2:
The patent segments the power supply system into multiple independent control zones: the RCD testing circuit, the load power supply circuit, and the backup power circuit. This segmentation allows the RCD to be tested without necessarily interrupting the load power supply, as each segment can be controlled independently
2Measurement precision
If the cutting device is opened to test the RCD, then the tripping time can be measured, but the load experiences apparent power loss and visibility of triggering is lost
Solution Approach 1:
The patent introduces a measurement device with current sensors and timing circuitry as an intermediary between the RCD breaking device and the measurement system. This device can detect the actual tripping event and measure the tripping time through electrical signal analysis, eliminating the need to visually observe the breaking device operation or experience apparent power loss
Solution Approach 2:
The patent replaces the mechanical/visual observation method of detecting RCD tripping with an electrical measurement system. Current sensors, voltage detectors, and electronic timing circuits substitute for visual inspection of the breaking device, allowing precise measurement of tripping time without mechanical intervention or visual visibility 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 continuous power supply during RCD testing and maintenance, ensuring proper tripping and insulation fault detection without disrupting sensitive loads, thus overcoming the limitations of prior art.
Implementation Method 1
an isolation transformer, installed in parallel with the breaking device associated with an RCD, comprising a primary connected to the electrical distribution upstream of the breaking device associated with a RCD
Data Source
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AI summary
The device has an isolating transformer (1) connected to a breaking unit e.g. differential switch, associated to a residual differential device (2), and including a primary side connected to a harness in upstream of the unit via a charging circuit-breaker (9) and a voltage presence monitoring device (10). A secondary side is connected to the harness in downstream of the unit and upstream of a load (3) via a phase selecting interface (6), a phase inversion device (7) and a coupling device (5). The sides are connected to the harness so that the transformer forms a secondary power supply.