In modern electricity metering systems, the Matching Relay Manganin Shunt, as the core sensing element for current sampling, plays a crucial role in converting large current signals into measurable voltage signals. Based on Ohm's law (V=I×R), the Shunt Terminal achieves accurate current measurement by measuring the voltage drop generated when current flows through a low-resistance resistor. Manganese-copper alloy, due to its extremely low temperature coefficient, excellent long-term stability, and good conductivity, has become the preferred material for manufacturing high-precision Static Copper Plates with Manganese. With the development of new energy sources, smart grids, and industrial automation, the performance requirements for copper manganese in electricity meters are constantly increasing, driving the technology to continuously evolve towards higher precision, lower power consumption, and greater integration.
Core Materials and Process Innovation: Breakthrough in Electron Beam Welding Technology
Traditional shunt terminals for magnetic latching relays often use tin soldering or silver soldering to connect manganin resistance elements to copper connectors. However, the presence of solder easily introduces additional resistance, thermal drift, and aging risks, affecting long-term metrological stability. In recent years, electron beam welding (EBW) technology has gradually become the mainstream process for high-end manganin shunts for electricity meters. This process utilizes a high-energy electron beam to directly fuse manganin and copper materials in a vacuum environment, without adding any solder, achieving metallurgical-grade atomic-level bonding.
Electron beam welding shunt assembly offers significant advantages: First, the solderless design eliminates resistance drift caused by solder joint oxidation and thermal fatigue, ensuring stable metering accuracy during long-term operation. Second, the extremely low thermal resistance and small temperature rise at the joint effectively suppress measurement errors caused by self-heating. Third, its high mechanical strength allows it to withstand lightning strikes of up to 3000A/10ms, and its oxidation and overload resistance far surpasses traditional welding methods. Furthermore, this process demands extremely high material purity and processing precision, reflecting advanced manufacturing capabilities, and has become the standard configuration for 0.5-level and above accuracy customizable copper manganin shunt resistors in medium- and high-power DC meters (such as charging piles and photovoltaic systems).
Evolution of Installation Methods: From Split-Type to Integrated-Type
Based on the installation method, electricity meter shunts can be divided into two main categories: external split-type and internal integrated-type. These two types differ fundamentally in structural design, performance, and application scenarios.
External split-type Manganin shunt resistors for current measurement are independent of the meter body and require connection via a sampling line. While offering flexible installation, they have significant drawbacks: long-distance signal transmission is susceptible to electromagnetic interference, and line impedance introduces additional errors; the use of 75mV or 50mV high-voltage signal output results in high resistance, leading to high power consumption (e.g., up to 22.5VA under 300A conditions), significant heat generation, and impacts system temperature rise and safety; the metering error is a combination of the meter, Manganese copper stamping, and wiring techniques, making the total error difficult to control, typically only suitable for accuracy classes 1.0 and below.
In contrast, the internal integrated Manganin shunt for single-phase latching relay directly encapsulates the manganese copper resistor inside the meter, forming an integrated structure. Its core advantages are: It employs a 6mV low-voltage signal transmission, resulting in lower resistance (e.g., 20μΩ), and power consumption is only 1/12 of that of a split-type system (approximately 1.8VA at 300A), significantly reducing heat generation and energy consumption; the sampling link is short and enclosed, avoiding external interference and wiring errors, achieving a metering accuracy of 0.5 class with an error stable within ±0.5%; it supports integrated lead seals to prevent tampering and improve metering impartiality; wiring is simplified, requiring only voltage and communication lines, increasing installation efficiency by over 50%, making it particularly suitable for space-constrained scenarios such as single-gun DC charging piles and vehicle-mounted energy storage systems.
Structural Specifications and Accuracy Level System
Structurally, the Electrical Meter Shunt follows a standardized design, with common models including the FL-2 basic type and the FL-29/FL-39 high-power types. The FL-2 model is suitable for current ranges from 1A to 15000A, with an output voltage selectable from 20mV to 100mV (standard is 75mV), and is widely used in AC and small-to-medium power DC energy meters. The FL-29/FL-39 models are designed for ultra-high current scenarios above 2000A, employing a high-temperature resistant isolation base to enhance overload capacity, and are suitable for industrial-grade high-voltage DC metering.
Accuracy classes are classified according to standards such as DL/T 2345-2021, into 0.2, 0.5, and 1.0 classes. Class 0.2 represents the highest accuracy and is suitable for laboratory calibration and key measurement; class 0.5 is the current mainstream high-precision standard, widely used in charging piles and photovoltaic systems; class 1.0 is suitable for general industrial and commercial metering. Accuracy depends not only on the performance of the manganese copper material but also closely related to the welding process, structural design, and temperature compensation mechanism.
Development Trends: Integration, Low Power Consumption, and Hybrid Sampling
Currently, Relay Resistor Shunt technology is exhibiting three major trends: First, in terms of manufacturing processes, electron beam welding is being widely adopted to improve reliability and environmental adaptability. Second, in terms of structure, the technology is evolving from discrete components to integrated systems, with built-in Manganese Copper Shunts becoming the technological iteration direction for DC energy meters. Third, at the system level, hybrid sampling schemes combining shunts and current transformers are being explored, balancing the requirements of large current measurement ranges and high accuracy, suitable for 1500V high-voltage, thousands of amperes energy storage and photovoltaic combiner scenarios.
Simultaneously, the application of new materials such as high-purity manganese copper alloys and composite metal films further reduces the temperature coefficient and long-term drift, improving stability over a wide temperature range (-40℃ to +70℃). Combined with PCB trace compensation, real-time noise monitoring, and software algorithm correction, modern Copper Manganese Shunt systems have achieved hardware and software co-optimization, ensuring metering accuracy in complex electromagnetic environments.
We focus on the research and development and manufacturing of high-precision energy metering components, providing Manganese Copper Shunts solutions that meet international standards. For technical consultation or customized services, please contact us for professional support.
contact us
