Compact Smart Meter Insulation Segmentation
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Solution Overview
Problem
Existing smart meters designed for top-hat rail installation in distribution boxes are large due to high safety requirements for surge protection, particularly the need for 8 kV insulation between the data communication interface and the three-phase alternating current electronics, which cannot be achieved cost-effectively with small-sized components, leading to a multi-module system that is costly and complex to assemble.
Innovation Solution
A smart meter with a primary circuit for three-phase alternating current, a secondary circuit for the data communication interface, and a measuring circuit with a smart metering microchip, where the measuring circuit provides 3 kV insulation between the primary and secondary circuits, and the secondary circuit provides 8 kV insulation, allowing for a compact design using inexpensive components and meeting safety requirements with a single device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 8 kV protective insulation is provided between the data communication interface and the primary circuit, then safety requirements are met, but the smart meter size becomes large and cost increases
Solution Approach 1:
The protective insulation is divided into two separate insulation stages: first insulation (3 kV) between the primary circuit and measuring circuit, and second insulation (3 kV) between the measuring circuit and secondary circuit. This segmentation allows achieving the total 8 kV protection level while using smaller, more compact insulation components than a single 8 kV insulation layer would require.
Solution Approach 2:
The measuring circuit acts as an intermediary between the primary circuit and secondary circuit, with each interface providing 3 kV insulation. This intermediate measuring circuit enables the total 8 kV protection through cascaded insulation stages, allowing compact component design while meeting safety requirements.
2Reliability
If 8 kV protective insulation is provided between the data communication interface and the primary circuit, then safety requirements are met, but the manufacturing cost increases
Solution Approach 1:
The protective insulation is divided into two separate insulation stages: first insulation (3 kV) between the primary circuit and measuring circuit, and second insulation (3 kV) between the measuring circuit and secondary circuit. This segmentation allows achieving the total 8 kV protection level while using smaller, more compact insulation components than a single 8 kV insulation layer would require, thereby reducing manufacturing cost.
Solution Approach 2:
Instead of using a single 8 kV insulation component, the invention changes the insulation parameter distribution to two 3 kV insulation stages. This parameter change enables the use of more cost-effective, smaller insulation components that are commercially available and easier to manufacture, while still achieving the required total protection level.
3Reliability
If a multi-module system is used to provide data communication interface, then safety requirements are met, but the device complexity and assembly effort increase
Solution Approach 1:
The invention combines the data communication interface (secondary circuit) and the power measurement circuitry (primary circuit) into a single integrated smart meter device. The measuring circuit serves as a bridge with appropriate insulation, eliminating the need for separate modules and reducing system complexity while maintaining safety through the cascaded insulation structure.
Solution Approach 2:
The measuring circuit performs multiple functions: it measures power consumption from the primary circuit, provides 3 kV insulation protection, and interfaces with the secondary circuit for data communication. This multi-functionality eliminates the need for separate protective devices and communication modules, reducing overall system complexity.
Data Source
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AI summary
The smart meter (1) has a primary circuit that is provided with connections for three-phase alternating current (AC). An operating side (4) of secondary circuit is arranged with data communication interface (5, 6). A measuring circuit with a smart metering microchip is provided between the primary circuit and the secondary circuit. The measuring circuit in relation with the primary circuit and secondary circuit has insulation with specific dielectric strength. The secondary circuit relative to the primary circuit has a specific insulation.