Preamble

Research on the Evolution of Smart Meter Technology
ZHANG Chunhui¹, ZHANG Zhen²
(1. State Grid Shandong Electric Power Company, Jinan, Shandong 250001, China;
2. Huaneng Jinan Huangtai Power Generation Co., Ltd., Jinan, Shandong 250100, China)

Abstract: The smart meter has evolved beyond a simple electricity measurement device to become a core component of the smart grid, enabling efficient monitoring, prediction, and management of power consumption. This transformation did not occur overnight but represents a long journey from mechanical meters to electronic meters and finally to today's highly intelligent devices, with each technological breakthrough laying the foundation for subsequent advances. In the mechanical era, measurement relied on mechanical rotation and counting, whose accuracy and stability were compromised by wear and environmental interference. The advent of electronic meters, powered by rapid developments in electronics, enabled sampling and processing of current and voltage signals, dramatically improving measurement precision and stability while introducing remote meter reading and data processing capabilities. However, limitations in data processing complexity and communication capacity drove the emergence of smart meters, which integrate IoT, big data, and cloud computing to achieve real-time monitoring, analysis, and prediction of power usage. These devices not only measure electricity accurately but also provide personalized consumption recommendations and energy-saving solutions based on user behavior.

Communication technology has played a crucial role in this evolution. From initial wired communication to the integration of wireless public networks, wireless private networks, and power line carrier communication, smart meters now enable real-time communication and data sharing with grid management systems, making power management more intelligent and efficient while delivering convenient, personalized experiences. Nevertheless, challenges remain, particularly regarding data security and privacy protection. As smart grids continue developing, smart meters must achieve tighter integration and coordination with other devices for more efficient and reliable power management. Looking forward, smart meter technology will continue innovating. With further advances in IoT, big data, and artificial intelligence, smart meters will gain more powerful functions and performance, providing a solid foundation for industry intelligence and efficiency. Addressing challenges related to data security, technical standards, and costs will be essential to promote continuous development and application.

Keywords: smart meters; technological evolution; power grid

1. Design Features and Quality Assessment of State Grid Smart Meter Models

1.1 The Initial 2009 State Grid Standard Smart Meter

Design Features: The 2009 standard provided the first definition of smart meters, though the "intelligent" functions were rudimentary, leading to differing opinions. Compared with DL/T614-2007 "Multi-function Electric Meters," this new standard introduced hardware clock circuits, programming passwords, fee control, load recording, tiered pricing, preliminary outage reading applications, and ESAM module security authentication.

Quality Assessment: The 2009 standard was converted and supplemented from State Grid's 2008 "Electric Meter Type, Function, and Bidding Technical Specifications." Due to the short conversion timeline, the new functions and technical requirements lacked scientific and detailed verification and testing. The standard content was incomplete and ambiguous, resulting in many original design and manufacturing quality deficiencies. The primary issues were incomplete and fixed energy metering functions that could not be selected as needed by other grid specialties or provincial grids; non-standardized meter operation and procedures; and some suppliers lacking experience in smart meter design and manufacturing, particularly in software design, component screening, and production processes, leading to high failure rates during initial operation. Consequently, in July 2012, State Grid's Marketing Department issued the "Notice on Further Strengthening Smart Meter Quality Control."

Application Status: From late 2009 to mid-2013, State Grid procured 225 million units of the 2009 standard smart meters, investing approximately 46.8 billion yuan. Currently, about 127 million units remain in operation, accounting for 27.7% of the total installed smart meters. After mid-2013, the 2009 standard smart meter was discontinued from State Grid bidding.

1.2 The 2013 State Grid Standard Smart Meter

Design and Testing Features: Like its predecessor, the 2013 standard maintained incomplete and fixed metering functions that could not be selected on demand—a persistent flaw in the new standard. However, it introduced many innovative and practical requirements for metering performance and function expansion, including advanced metering chips, refined event recording, enhanced metering security, anti-theft measures against strong AC/DC magnetic fields, technical specifications for 15 major components, province-wide centralized and unified automated verification, and gradual configuration requirements for HPLC and gateway functions. Nevertheless, the 2013 standard smart meter failed to meet the requirements for domestic implementation of the OIML IR46 standard.

Application Status: From mid-2013 to 2019, State Grid procured 400 million units of the 2013 standard smart meters, investing approximately 83.2 billion yuan. Currently, about 331 million units are in operation, representing 72.7% of the total. These meters were originally scheduled for replacement in 2019 by the "dual-core" smart meter—the first new-generation model. However, due to changes in State Grid's development strategy between January 2019 and January 2020, the 2013 standard smart meters continue operating. On April 19, 2020, online reports indicated that the first batch of 2020 smart meter bidding totaled 24.752 million units with a value of 4.26 billion yuan, suggesting that State Grid's procurement still favored the 2013 standard.

1.3 The 2016 State Grid Design: IR46-Based "Dual-Core" Smart Meter (First New-Generation Model)

State Grid's "Design Scheme for IR46-Based Dual-Core Smart Meters" represented the first domestic implementation outline for OIML's IR46 standard.

Design Features: To implement IR46's metrological characteristic protection requirements, the dual-core architecture adopted a separated design with independent metering and management cores, departing from the integrated architecture of previous smart meters. Specific technical designs included dual-MCU and dual-memory solutions, voltage/current sampling or instantaneous value measurement, time-stamped energy data, more reliable real-time clock power supply design, HPLC communication, and online management core software upgrades.

Design Assessment: The dual-core smart meter's naming was inappropriate and the design content incomplete, with many missing elements. The term "dual-core" only indicated implementation of IR46's metrological characteristic protection, yet IR46 Part 1's core content includes both accuracy requirements and metrological characteristic protection, with the new accuracy system being more significant. The design scheme comprised six sections (meter type design, structural design, interface definition, metering core requirements, management core requirements, and dual-core testing) and four appendices (communication protocols, management core program upgrades, etc.), but lacked specific explanations for how to incorporate IR46 Part 1's accuracy requirements, software separation requirements, and Part 2's measurement control and performance testing. It also failed to address conventional smart meter design aspects including functional positioning and overall architecture, hardware/software design and testing, reliability design and verification, process design and testing, and type testing.

Project Lifespan: The dual-core smart meter project lasted only four years from initiation to pilot operation: project initiation in January 2015 (State Grid Marketing Department Document [2015] No. 53), design scheme release in September 2016, prototype development by domestic manufacturers in 2017, pilot operation in Zhejiang grid in November 2018, and transition to a technical reserve product in January 2019 when State Grid proposed alternative positioning and expanded functional requirements.

1.4 The 2019 State Grid Technical Requirements: Multi-Core Modular New-Generation Smart Meter (Second Model)

In June 2019, State Grid launched the second new-generation smart meter prototype, whose performance and functions encompassed both IR46 standard implementation and the alternative positioning and expanded functional requirements proposed in January 2019.

Design Features: The key difference from previous smart meters was its multi-core modular architecture. The multi-core design featured separated metering and management cores, expanded energy metering types from sinusoidal active/reactive power to fundamental active/reactive power and harmonic active power, increased active energy collection and freezing cycles from 15 minutes to 1 minute, proposed 10 legal-related and 7 non-legal software testing requirements, and extended service life from 8 to 15 years. The modular design included metering core modules, management core modules, and expansion function modules interconnected as a measurement system, with three typical application scenarios: electric vehicle orderly charging, residential load characteristic intelligent analysis, and "multi-meter integration" information collection.

Subsequent Development Needs: Following the prototype launch, the author identified necessary research topics including development of series product standards covering all performance and function designs for the new-generation three-phase smart meter, and new technology application development projects (detailed in Section 3.1).

Application Status Changes: In January 2020, State Grid adjusted its development direction, altering the trajectory of the second new-generation smart meter. The author contends that while the multi-core modular architecture represents a revolutionary departure from traditional integrated designs and the expandable function modules meet on-demand requirements, the product design issues stem from these very expansion modules. The alternative positioning and expanded functional requirements proposed in January 2019 included three application scenarios that now require re-evaluation to determine whether they are viable, improvable, or unsuitable under the adjusted development direction.

2. Comprehensive Review of State Grid Smart Meter Development (2009-2020)

2.1 Major Achievements in 11 Years of Development

Universal Coverage: By the end of 2018, State Grid achieved 99.87% user coverage with 458 million smart meters in operation, marking the second turning point in China's meter development history—the transition from induction and electronic meters to smart meters as the dominant grid measurement device. (Note: The first turning point occurred in 2005 when electronic meter production first exceeded induction meters.)

Unified Quality Management: State Grid established unified product standards (2009 and 2013 versions), unified manufacturing quality supervision (enhanced component specifications, high-temperature aging processes), and unified testing (province-wide centralized automated verification by provincial grid academies). A large-scale sampling inspection in August 2018 of 360,000 meters operating for 7 years yielded a 99.64% qualification rate, demonstrating satisfactory quality and stability, though questions were raised about the statistical methodology given high initial failure replacement rates, particularly for 2009 standard meters.

Enhanced Functionality: Building upon DL/T614, State Grid successively introduced new functions including fee control, tiered pricing, 1-minute active power collection/freezing cycles, time-stamped energy data, hardware clock circuits, programming passwords, outage reading, anti-magnetic theft measures, management core software upgrades, voltage/current waveform data output, proactive low-voltage grid outage reporting, and ESAM security authentication.

Architectural Innovation: The shift from integrated architecture in traditional electronic/previous smart meters to multi-core modular architecture in the new-generation meter represents a significant leap. The separated metering and management core modules accommodate IR46 implementation, while expandable function modules provide practical on-demand flexibility.

Operational Reliability: The 2013 standard smart meter, developed by addressing 2009 version defects and incorporating innovative functions, has demonstrated stable and reliable performance over seven years of operation. With 331 million units installed (72.2% of the total), it is expected to remain the primary procurement choice for the next 2-3 years.

2.2 Development Problems (2009-2020)

Rapid Development Cycles with Insufficient Consideration for Replacement Costs: The statutory 8-year verification cycle suggests new smart meters should operate longer than 8 years, yet:

• Case 1 (2009 Standard): High failure rates and non-standardized functions led to discontinuation after only 3.5 years of operation. Of the peak 225 million units installed (46.8 billion yuan investment), only 127 million remain, with complete replacement expected within 3 years.

• Case 2 (Dual-Core Project): Initiated in 2016 while 2013 standard meters had only been operating for 3 years, this premature launch aimed to pioneer IR46 domestic implementation. However, IR46's limitations (focusing only on active energy meters while other types remain under development), incomplete IEC standard adoption, and challenges in applying IR46 comprehensively to multi-type State Grid standards led to its termination after 4 years, becoming merely a technical reserve.

Initial Design Deficiencies:

1. Inadequate "Smart" Functionality: The 2009 standard provided only a basic definition without advanced interactive capabilities between distribution networks and users. International examples (GE, Hangzhou Haixing, German specifications) emphasize bidirectional communication, gateway applications, and autonomous decision-making. State Grid's meters lacked these advanced interactive functions, with ongoing disagreements between marketing/metering and distribution departments. The initial positioning of State Grid's information collection system as AMR (Automatic Meter Reading) rather than AMI (Advanced Metering Infrastructure) contributed to this limitation.

2. Incorrect Metering Function Positioning: Fixed and incomplete metering functions restricted selection by other grid specialties and provincial grids. While international designs offer selectable single-phase meters with 1, 0.5, or 0.2 accuracy classes and full-power metering (active, reactive, apparent), State Grid's single-phase meters only offered Class 2 accuracy (with ±0.6% factory error control), which the author argues is unreasonable. Proposed improvements include using 0.2-class meters for users consuming ≥500 kWh/month, 0.5-class for ≥200 kWh/month, 1-class for ≥100 kWh/month, and 2-class for others, plus load curve monitoring for ≥200 kWh/month users with alarm functions for deviation from typical patterns.

3. Unreasonable Accuracy Class for Single-Phase Meters: The uniform 2-class accuracy with ±0.6% error control is inflexible compared to international practices offering multiple accuracy classes for different consumption levels.

New-Generation Meter Issues: The second new-generation meter's design, combining IR46 implementation with alternative positioning and expanded functions from January 2019, requires re-evaluation following State Grid's January 2020 direction adjustment.

3. Expectations for State Grid's New-Generation Smart Meters

3.1 Redesign and Extended Pilot Testing Required

Redesign Components:
- Re-evaluate alternative positioning and expanded functional design
- Develop technical specifications for EV orderly charging metering
- Establish algorithms, assessment methods, and application specifications for residential load identification
- Create software testing requirements and application specifications
- Conduct reliability论证 and testing for 15-year service life
- Revise DL/T698.45 data communication protocol for new-generation meters

Address Initial Design Deficiencies:
- Enhance "smart" functionality, particularly bidirectional communication and gateway applications with autonomous decision-making capabilities for advanced user-grid interaction, including large-capacity residential and commercial equipment coordination, demand response, real-time pricing, and power market transaction metering.
- Open full-power metering functions for on-demand selection by grid specialties.
- Implement multiple accuracy classes for single-phase meters based on monthly consumption assessment.
- Deepen software testing research, expand testing scope, and improve efficiency.
- Reduce initial installation failure rates through improved reliability design and testing.

Domestic High-End Meter Development: State Grid should collaborate with industry authorities to promote domestic high-end meters for grid gateway applications, develop high-reliability, high-stability, long-life technical specifications, advance domestic high-reliability component production, conduct reliability design论证 and service life testing, and arrange parallel operation with imported meters to accumulate long-term data and achieve comprehensive domestic substitution.

Forward-Looking Metrology Research: Concurrently conduct advanced research on sinusoidal full-power metering, ultra-low power factor metering, fundamental wave metering, non-linear load metering, and direct 10-35kV high-voltage metering to improve operation quality, reduce grid losses, suppress harmonic pollution, and improve large-user metering mechanisms. Recommend reforms to international standard development mechanisms to increase Chinese industry participation in IEC and IEEE standards, accelerating the introduction of international metrology technologies.

3.2 Need for Long-Term Development Planning

Reviewing 2009-2020 reveals a曲折 development process with significant achievements but also unresolved research challenges. Based on accumulated quality management experience and new requirements for energy internet enterprise construction, State Grid should develop a long-term smart meter development plan incorporating international metrology and communication technologies.

4. 2021 Market Demand and Emerging Issues

As 2022 approaches, this paper summarizes 151 articles on new-generation smart meter market and technology development for new power system construction, extracting five influential categories: domestic market, international market, renewable energy grid integration metrology, information collection system updates, and user-side IoT applications.

4.1 2021 State Grid Procurement: 28.2% Year-over-Year Growth

In 2021, State Grid procured 66.736 million new-generation smart meters in two batches (30.402 million and 36.334 million units) totaling 16.97 billion yuan, representing a 28.2% increase from 2020's 52.056 million units. Growth drivers included:
- First year of new-generation meter deployment
- Replacement of 430 million non-IR46-compliant meters (2009/2013 versions) requiring 53.7 million units annually over 8 years
- New user growth (15 million units at 3% of 510 million users)
- Batch application of smart IoT meter functions
- Expanded application of domestic high-accuracy gateway meters
- Fault replacement demand (2.55 million units at 0.5% of installed base)

Price Increase: The 2021 average unit price was 254.28 yuan, 19.6% higher than 2020's 212.6 yuan.

2022 Outlook: With 376 million legacy meters remaining and 53.7 million requiring annual replacement, plus new demands from renewable energy integration and IoT functions, 2022 demand is projected at 60 million units. However, the 6% cap on individual supplier awards limits enterprise development, prompting companies to explore high-end meters, industrial markets, and international expansion.

4.2 Progress in Gateway Meter Localization

Over 20 years, Wasion has introduced high-end technologies including 0.1S-class active energy metering, non-linear load metering, and harmonic metering. In 2010, Wasion developed China's first 0.1S-class high-accuracy settlement three-phase gateway meter using digital multiplier technology, featuring fundamental/harmonic metering, satellite timing, and power flow detection. Employing proprietary algorithms (compound Newton-Cotes high-order integration for active power, reactive power algorithms, high-precision dynamic angle difference compensation) and international high-performance components, the meter achieves ±0.04% active power error and ±0.1% error over 15 years, reaching international advanced levels and breaking import monopolies. Currently deployed at inter-regional grid tie-lines, provincial substations, large renewable energy connections, and electrified railway traction stations, it has demonstrated stable, reliable performance.

4.3 Smart IoT Meters with Non-Intrusive Load Identification

In July 2021, Hunan Power pilot-installed 543 smart IoT meters in 5 low-voltage stations in Changsha and Xiangtan. Equipped with non-intrusive load identification modules capturing high-frequency voltage/current waveforms, these meters use appliance characteristic combination algorithms to identify individual appliance consumption and timing. Additional features include harmonic metering, terminal temperature measurement, and self-monitoring of metering errors, extending service life from 10 to 16 years. These capabilities enable early warning of overheating risks, address metering blind spots for high-speed rail and telecom towers, and detect high-frequency interference from distributed generation, EV charging, and harmonic pollution sources. Hunan Power plans to deploy over 1,000 units in 2021.

4.4 Jiangsu Power: Multi-Core Modular Load Analysis Meters with Remote Software Upgrade

Previous non-intrusive load analysis required on-site module replacement for function upgrades, hindering large-scale application. While domestic standards prohibit online software upgrades, IR46's requirement for independent metrological and non-metrological hardware/software systems enables remote upgrades without affecting metering performance. The new meter design incorporates a metering core, general function core, and dedicated load analysis core, enabling residential load identification and online feature library updates through the information collection system. The remote system includes specialized communication topology and load matching algorithm upgrades. Using Mahalanobis distance-based multi-layer tree classification algorithms, the meter achieves 95-98% identification accuracy for single appliances and 70-90% for mixed loads, demonstrating accurate identification of typical household appliance consumption details without affecting metering performance.

5. International Smart Meter Market: Demand Growth and Intensifying Competition

5.1 Market Overview

Globally, 230 countries have approximately 7.5 billion people, with 89% (6.675 billion) having electricity access across 1.335 billion households. About 1.7 billion meters are in service, with 963 million smart meters deployed by 2020 (59% penetration), indicating 737 million units of remaining demand and sustained market growth. China leads with 62% of global smart meter installations, followed by North America, Europe, Asia (excluding China), Latin America, and Middle East/Africa. Major international suppliers include Landis+Gyr, Itron, GE, and Elster.

Chinese Exports: In 2020, Chinese enterprises exported meters to 160 countries/regions, shipping approximately 59 million single/three-phase smart meters worth over $1.3 billion (8.4 billion yuan) at an average price of $30.7 (200 yuan). Leading exporters include Hangzhou Haixing, Wasion, Kaifa, and Holley, with Haixing exporting $280 million (1.8 billion yuan).

5.2 Landis+Gyr: A Century-Old Brand

• 1993: Produced ZU-type 0.2S-class high-precision gateway meters using time-division multipliers
• 1995: Launched ZB-type 0.5S-class static three-phase meters based on Hall-effect multipliers
• 1998: Shandong Grid imported Landis+Gyr's automatic billing system with ZU meters and FAT processors
• 2004: Developed ZQ-type 0.2S-class high-precision settlement gateway meters using digital multipliers
• Early 2000s: Developed AMI infrastructure and Grid Stream command system
• 2016: Created mesh routers enabling multi-grid AMI solutions
• 2019: Partnered with Tokyo Electric Power to deploy over 20 million smart meters using IEEE802.15.4 Wi-SUN mesh networking
• 2021: Acquired Turkish supplier Luna for $60 million annual revenue, gaining market access and vertical integration capabilities; signed a 10-year, 2.3 million-meter contract with New Jersey's PSE&G using Grid Stream Connect AMI platform

Transformation: Since 2017, Landis+Gyr has evolved from a metering supplier to an advanced network and IoT solutions provider, generating $1.6 billion annual sales as an independent platform under Toshiba, delivering comprehensive smart grid solutions across 30+ countries.

5.3 Promoting High-Quality Chinese Smart Meters and AMI/AMR System Exports

Saudi Arabia Project: In April 2021, State Grid's China Electric Power Equipment and Technology Co. completed a landmark project deploying 5 million smart meters across western and southern Saudi Arabia. NARI Group provided the AMI/AMR solution, overcoming challenges including NB-IoT communication scaling from 5% to 50% through a short-connection meter reading scheme for million-level device access. The system manages 7.5 million meter connections with heterogeneous communication support and billion-level data storage/processing. Domestic suppliers including Linyang (330 million yuan), Ningbo Samsung (450 million yuan), Chint (over 100 million yuan in components), and Kaifa (2.4 million meters) participated, with NARI implementing the master station system.

Wasion's Global Expansion: Wasion Brazil and Mexico signed contracts exceeding 100 million yuan and 260 million yuan respectively in 2021. With 20 years of international experience, Wasion has expanded from power metering to water, gas, and thermal metering, and from products to comprehensive solutions and engineering services. Overseas business accounts for 15% of its 4 billion yuan 2020 revenue, with products sold to 50+ countries and factories in Tanzania, Brazil, and Mexico.

Market Strategy: While the domestic State Grid market is stable but limited by the 6% award cap, Chinese meter enterprises have achieved significant export success, capturing 50% of global market share for electricity, water, and gas meters. The Saudi project represents the first comprehensive export of meters and collection systems (including master stations), demonstrating the viability of product exports, semi-knocked-down exports with local assembly, and overseas manufacturing/joint ventures, primarily targeting Asia, Africa, and Latin America.

AMI Development Requirements:
- High-Quality Meter Development: Domestic meters can achieve international medium quality at low prices but haven't entered high-end markets. International quality standards include strict factory error control (40% of class for general meters, 25% for gateway meters), influence quantity indicators at 50% of standard requirements, flat error curves with 20% linearity, low internal temperature rise, and guaranteed accuracy throughout service life. Landis+Gyr's proprietary metering algorithm chips enhance reliability and security.
- AMI System Design: Most domestic enterprises lack experience in AMI command systems and master station/platform design, requiring increased investment and talent recruitment. Design should reference Landis+Gyr and NARI experiences, incorporating international functional requirements with flexible system modifiability.
- User IoT Applications: Local communication technologies (HPLC, Wi-SUN, narrowband wireless) must be validated against local residential density, climate, and communication media. Wi-SUN shows promise as a core IoT protocol, as demonstrated in Tokyo Electric Power's 20 million-meter deployment, offering end-to-end addressability, wide coverage, security, and scalability for smart home applications.

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