1, the lack of break induction table
After years of China’s large-scale transformation of urban and rural power grid construction, China’s induction technology and quality table has more start-up has been significantly improved. Advanced countries, especially in light of the experience, designed for long life and sub-induction meter long life, and to develop the relevant standards. However, compared with foreign brands, our induction meter there is a gap, mainly for poor performance, consistency, quality of materials and critical technology issues are not resolved and so on.
2, rapid technological upgrading electronic form
Residents with a table function is growing. Years of urban and rural residents a renovation project in a table, electronic energy meter case to promote the use of large area, and has been widely recognized by users, to 2005, domestic consumption of electronic energy meter induction over the table. Ordinary civil life of electronic energy meter to ensure that 15 or even 20 years. The electricity sector of the electronic energy meter requirements are not satisfied merely with the measurement function, they use the table of the functional requirements of the residents are growing. Integrates many features of the new residents have been using the table on its hardware and multi-rate tables, pre-paid form, such as almost no difference between the carrier sheet. Enhancements greatly improve the electricity supply sector of the population of modern management, the new residents of the electronic energy meter to achieve more in the future provide the basis for large-scale automatic meter reading.
Rapid development of multi-rate table. Since 2000, Shanghai started the first large-scale use of multi-rate table has a lot of multi-rate table for the power shortage in economically developed areas of the electricity sector in favor of China all of a sudden become the world’s population with the largest number of multi-rate table State residents with more technical and therefore the rate table to quickly improve and develop. With the market for functional and performance requirements continue to increase, residents of the table with a multi-rate techniques have also gone through several generations of evolution, in particular, and multi-rate characteristics of related tables display, real-time clock accuracy, communication means, communication Statute and so has made great progress, the main manufacturers of the product technology is mature, stable and reliable quality. With electricity demand management and energy-saving, multi-rate table to get more customers.
Into industrial and commercial use multi-table trend. As early as the beginning of this century, electronic energy meter has been replaced by induction on the table, a table of the main industrial and commercial use, but in recent years the demand for three-phase multi-function table showing a rising trend, mainly because of the power system in the expanding three-phase multi-table applications, not only that, three-phase multi-rate tables, three-phase combination significantly increased the demand for the table and have three-phase multi-function table is closer to, grouped into one class . Current ordinary domestic functions and performance of multi-table and import tables have been comparable, but significantly better than the import price table, 0.2S-level table has also been made using bulk, harmonics measurement, means of communication, network management functions While growing, but made a wide range of multi-function meter communication protocol, incompatible, reliability needs to be further strengthened.
Prepaid Table gradually perfecting. Pre-paid table after several years of silence, from 2006 onwards there was signs of recovery, this is due to the electricity sector to increase the intensity of the management of delinquent customers, the market demand is heating up again, also because of After years of continuous improvement of manufacturing, especially in parts of the IC card hardware and software improvements, the use of the CPU card and contactless cards, the latest technology, and technical conditions of unity, so that the performance of pre-paid form, especially security and reliability has been gradually perfected, at the same time, built-in quality and capacity of the relay also improved significantly.
Automatic meter reading technology promising. In the late 1990s, some areas of the power sector began a large-scale low-voltage power line carrier technology, but because of haste, use of less effective. In recent years, advances in communication technology as well as electricity market applications, the level of domestic automatic meter reading technology has made considerable progress. Particularly GSM / GPRS and CDMA communication technology has a large customer meter reading and management system has been widely used and has been successful, low-voltage power line carrier technology has gradually been more and more adopted in the electricity sector, the effect is generally satisfactory , while the short-range wireless meter reading meter reading, especially the residents are also three tables set copy and rural residents get the meter reading application and promotion.
3, various types of energy meter technology, the main problems
(1) induction table
Compared with foreign brands, our induction meter there is a gap, mainly as follows:
Consistency of performance is poor. Specific performance data, poor repeatability and consistency. Our induction meter automated production level is not high, most still manually processing methods mainly due to the involvement of the production process in manual too, is difficult to guarantee a high degree of consistency of product performance, but also increased the difficulty of production management.
Material quality problems are not resolved. Induction meter to measure the lifetime guarantee accurate and reliable, must ensure that the structure of the long-term stability, the key energy meter parts have enough ability to adapt to a variety of harsh environment, which requires induction meter of the rotating element adequate wear characteristics, magnetic materials have magnetic properties and other long-term stability requirements. As the materials industry in China and the developed countries there is still a wide gap, a company how to detect, the choice of key components (such as magnetic thrust bearing, the damping magnet, etc.), is currently the issues to be addressed.
The key technology is not resolved. In addition to a more comprehensive selection of qualified design and materials, induction meter to achieve long life must also have reliable processes. Coil winding, core punching rivet system, the production of graphite bearings, magnetic thrust bearing is also a need to address aging issues.
(2) Electronic form
The display. Meter display is an important component, the original use of mechanical counter and when the counter and there is a certain percentage of cards of words and the probability of dislocation, and higher in the anti-tampering, its weakness against magnetic interference are more vulnerable to poor illegal users of the attack, although the increase in non-return device can be used to prevent the reverse, increasing the thickness of the motor shield reduced the magnetic field disturbances, but can not fundamentally solve the problem. LCD and resolves the above problems, but some manufacturers use the LCD display quality varies, especially in the ultraviolet radiation, high temperature and high humidity, low temperatures prone to problems.
Software reliability. Electronic energy meter case is a distinctive feature of the hardware manufacturers to use more and more close, and more and more features through software to achieve, so the reliability of the software largely determines the reliability of the meter itself. The quality of the hardware itself can be based on technical parameters and indicators, and through the associated experiments to verify its reliability, performance and quality, and reliability of the software is no good in the final product means you can quickly check out the normal various test cases, software may be running normally, but in some interference or unusual circumstances, if the software for these ill-considered, will be prone to problems.
Communication protocol. At present, the electronic energy meter regardless of communication interface, generally following the DL / T 645-1997 “multi-function meter communication protocol.” With the power sector continues to develop modern management, the existing DL / T 645 of the Statute has been in many respects, the meter can not meet the functional requirements, manufacturers need the new features are on the DL / T 645 extends the statute, but all manufacturers are mutually incompatible, there is no unified record management; the local power sector due to the local needs of the sector and the development of modern management, but also on the DL / T 645 extends the statute, and will be updated from time to time. Because of the lack of a unified communication protocol planning and management, the current communication protocol has been very confusing, leading to both the use of DL / T 645 of the Statute of the various manufacturers of the meter can not be interconnected in the same area at different times of the meter can not interoperability, coupled with various meter manufacturer, acquisition device manufacturers, software providers on the DL / T 645 is also biased understanding of the statute, may also lead to “even with the same communication protocol can not be interconnected” to happen.
Harmonic measurement. When the power source line with the presence of harmonics, harmonic power load will cause the non-linear waveform distortion. Harmonic case, the user side of the energy can be divided into fundamental input power, harmonic input power and harmonic output power, and linear load user should only be consumed by the fundamental input power, should not be included in the harmonic input power, users more pay; when the load is nonlinear, the load usually produces harmonic output power, then the user will also generate pollution but less pay. Currently, some manufacturers use DSP technology in addition to its own energy metering algorithm under accurate measurement of harmonics, the most dedicated digital multiplier chip can measure accurate measurement of harmonics user. This is usually measured in the residential customers there is no problem, but in the harmonic generation on a larger industrial metering will bring a greater injustice.
Multi-function table definitions. With the continuous development of multi-table technology, the electricity sector for multi-user functional requirements of the table more and more, in addition to the more standard variety of measurement data and reference variables, raised more information about power quality detection functional requirements, such as the quality of light there is for the off-phase voltage, overvoltage, undervoltage, loss of pressure, total loss of pressure, voltage unbalance, voltage distortion, voltage qualification rate, but many of these features is not clearly defined, or individual users have different definitions, resulting in a function the same for different users to different changes, if not as soon as possible to develop standards for uniform definition of multi-table feature will result in more and more confusing, is not conducive to multi-table technological progress.
The reliability of power line carrier technology. As the low-voltage distribution network of the most extensive coverage throughout every corner of every household, where there had stretches where the meter network, so residents of automatic meter reading is the most convenient and most economical communication channel, and no monthly fees. However, due to the complex structure of low-voltage power grid network, lack of planning, grid serious pollution and other reasons, resulting in a power line carrier signal attenuation is very serious, very large signal to noise ratio down the situation, although the PLC technology has made significant progress, the communication was successful rate has increased, and in some places of the pilot countries have relatively small ideal, but in large scale in carrier reliability of the technology to be further verified.
Energy meter industry technology trends and focus.
4, a comprehensive alternative to electronic energy meter sensor table
Electronic energy meter is able to replace the sensor table and become the darling of the market, has many advantages: ① reliability: accuracy for a long time constant, no round school, no installation, transportation impacts; ② Accuracy: Wide range, wide power factor, start-sensitive, anti-submarine and reliable; ③ Function: centralized meter reading, multi-rate, pre-paid, anti-tampering, multi-functional; ④ cost: cost-effective, can be reserved for extensions, up by raw materials price impact on small and so on.
Further enhance the performance measurement
With the electronic energy meter technology continues to progress, there are more users concerned about the meter’s range, light load accuracy, low power factor accuracy, starting sensitivity, anti-creep reliability, and accuracy of measurement of harmonics, etc. characteristics. They asked: ① wide range :8-10 rate as more and more users choose, or even require 20 magnification; ② High accuracy: accuracy and the actual starting current required to achieve the level of 50% or higher level; ③ affect the amount of more demanding: the amount of influence are more demanding, especially the amount of interference, such as the external magnetic field; ④ voltage, current, power, power factor, real-time parameters have higher accuracy requirements; ⑤ nonlinearity measurement accuracy: not only active but also reactive power.
Three-phase multi-function table of a further breakthrough in performance measurement
As the national grid and construction of large-scale transformation and economic growth accompanied by rapid expansion of a large number of users, high-end three-phase multi-function table to be more widely used. 0.2S scales, especially the gradual domestic use, so that the power users more than ever concerned about the energy measurement of the correlation algorithm, in particular, the measurement of nonlinear algorithms operating conditions, they are increasingly focusing on are: ① harmonic conditions can to provide both the active and reactive fundamental, harmonic, with a total power and other data; ② harmonic reactive conditions the accuracy of measurement; ③ accurate measurement of the transient load. ④ harmonic analysis function and practicality; ⑤ more accurately determine and record the state, especially a variety of transient, transient and steady-state parameters; ⑥ the further expansion of range and accuracy; ⑦ diversification of means of communication, network technology and interchangeability.
LCD monitors wheel speed counter and replace the word
LCD has been able to get more and more recognized by customers, mainly because: ① LCD reliability and life has been widely recognized by industry; ② LCD monitor can display more information (character prompt, multi-row display, etc.) ; ③ LCD than the word round counter and a better anti-theft; ④ meter reading data and manual meter reading data consistency requirements; ⑤ LCD display with low power consumption can be displayed when the power outage; ⑥ LCD display is also in the dark can be used to backlight display.
LCD monitor future trends and focus is to ensure its quality, increase service life, ensure that the requirement to meter machine life, especially in the anti-ultraviolet radiation, high temperature and humidity, low temperature further increased.
Further strengthen the anti-tampering requirements
With a more diverse way of stealing and covert, anti-tamper requirements for watt-hour meter is also increasing, which has become increasingly inadequate mechanical, electronic energy meter is showing a strong advantage.
There are currently stealing ways: interference measurement device, change the connection mode (Figure 1 form for the single-phase power line diagram of power stealing mode), open the cover to change the internal wiring or data. These will require electronic energy meter in the anti-tampering in the direction of the following: ① to strengthen the shield or the use of measurement devices more powerful anti-interference measurement device; ② strengthening the ability to detect abnormal wiring and records, such as increasing the current imbalance detection sensitivity; ③ alternative measure to provide more data, such as table provides split-phase three-phase metering function, single-phase single-line table provides measurement functions; ④ enhanced shell structure, so that the meter is difficult to be open, or open the surface significantly traces, and a permanent record; ⑤ greater variety and number of abnormal event logging.
A communication interface RS485 interface has become the trend, especially
With the gradual implementation of meter reading, home and power sector reform, automatic meter reading to become a strong user demand, so more and more meters with communication interface requirements. The current means of communication in one or several more or less there are some problems, can not fully meet user requirements. The meter is equipped with RS485 interface with a mature and cost advantages for the future use of newer, better communications technology, users now become the ideal choice gradually become the standard configuration.
The requirements of the communication interface further improved, such as anti-static, anti-lightning surge indicator, anti-man-attack capabilities. At the same time, carrier communication system, thanks to the power inherent in the unique advantages of the network, but also has been widely appreciated, and anti-jamming capability, and network protocols and other aspects of further development. Three-phase multi-function table and end products such as power distribution, communications need to transfer more data and demanding communication success rate, while the public network wireless satisfy such requirements, and therefore get more and more used.
Power line carrier applications to accelerate growth
As communications technology continues to evolve and automatic meter reading to become a strong demand for users to promote the dual forces, in particular, more and more users have selected the meter with RS485 interface, the next meter reading program must be focused, and Power line carrier is still the most desired meter reading means the user, so even large companies and foreign manufacturers of power line carrier communication technology studies into more power, and anti-attenuation, noise, anti-distortion, the efficiency of sending, receiving sensitivity, and other network functions have made considerable progress. Meter manufacturers to optimize their software and hardware design, power line carrier reliability has been improving, and in many applications in the field success. Power line carrier technology trends integrated use of various technologies, comprehensive development of the indicators, to ensure communication reliability, and further added data security.
Real-time clock and the increasing demand for related functions
In recent years, the use of multi-rate table is constantly expanding, especially in economically developed regions such as Shanghai, Jiangsu and other regions is growing rapidly. In 2005, the multi-rate table has been occupied electronic energy meter 20% of the share. In the ordinary form, the communication interface with the LCD display and the extensive use of real-time clock and associated functions are more requirements.
Real-time clock and the reasons for rapid growth-related functions are: ① the widespread use of multi-rate tables, especially single-phase multi-rate tables wide use; ② late electricity billing, line loss statistics accuracy, consistency requirements; ③ events record-keeping requirements, such as the local operating records, unusual events are stored, the command records. Multi-rate tables of the accuracy with real-time clock accuracy is directly related to electricity, so accuracy is very high, so more and more users require the use of temperature compensation in order to achieve high accuracy within the whole temperature range. For ordinary tables, because of cost considerations, you can allow the use of MCU software clock.
Modular design to trend
Electricity market and rapid technological progress in recent years, reform efforts in the larger, and thus the speed meter technology updates also put forward higher requirements, and various parts of the technical conditions for the management of their own characteristics, have different technical requirements, So each meter and have a variety of different versions, which also requires a single meter for meter manufacturers have significantly improved the speed of development, and can ensure high reliability.
In order to better solve this problem, modular design will become a trend. Whether it is hardware or software can be a modular design, the technology is relatively mature and part of the standard package storage, such as the measurement module, power module, RS485 module, RTC module, display module, the relay control module, IC card module, data storage module, these modules have been through rigorous internal testing, production and use in the field of verification. When designing a new product, developers only need to focus on new products, modules, development of new features, as well as the integration of the module, so not only shorten the product development cycle, but also improve the reliability of the product design.
Need for a unified standard communication protocol
Current DL / T 645-1997 “multi-function meter communication protocol” for nearly 10 years old, the Statute of the content in many ways, the meter can not meet the functional requirements, so users and manufacturers of new definitions of data items Since the definition of the statute, resulting in data identifies conflicts and confusion, the statute resource utilization is low, while the interpretation of the statute is not clear, resulting in understanding of the differences. Therefore, regardless of the power sector users or manufacturers, are hoping for meter communication protocol be revised and improved in the new generation of communication protocol, you should also consider new technologies, new features extend the applicability and future management of the Statute.
Manufacturing and industry sector response
Emphasis on research and validation of measurement techniques
The core function is to measure the meter, so manufacturers have to pay attention to measurement techniques, especially high-end measurement techniques, to master its own power algorithm, because the meter can not be many other features at the expense of core technological progress meter . Industry sectors on how to verify the accuracy of the meter algorithm to work hard, and to develop related industries as well as national standards.
Enhance the reliability of key components of research and verification methods
LCD displays, batteries and other important components affecting the life of electronic energy meter to further improve, so manufacturers have to improve its reliability and how to study life. Industry sector to develop a validation study of the effectiveness of these components model and its verification method.
Reliability First, the cost of the second
Manufacturers should pay attention to the reliability of hardware and software designed to take full account of the complexity of the meter operating environment, hardware design margin and should be fully protected, software design, there is full redundancy and error correction, the test must be fully on equipment and methods. Users can not light the power sector and the pursuit of low prices, quick delivery and reliability for manufacturers in the design of the cost of sufficient space on the reliability of the test allow sufficient time.
Strengthen the research and application of communication technology
Meter of the core is to obtain accurate and timely measurement data, manufacturers should strengthen the communication of new technology research and applications, including local communications technology and telecommunications technologies, such as power line carrier, short-range wireless, mobile communications, wired and wireless networks . Industry sectors to actively be on the new communication technology applications and support.
Designed to enhance standardization, uniform standards
Manufacturers actively promote the new product should also strengthen the standardization of design, function modules will mature gradually standardized, in order to ensure the quality of new product design and speed. Industry sector should strengthen the importance of standards and research, timely introduction and improvement of standards, to strengthen the compatibility of the various manufacturers products, so as to fully avoid the risk of the meter industry standards, competitive and orderly manner.
3, various types of energy meter technology, the main problems
(1) induction table
Compared with foreign brands, our induction meter there is a gap, mainly as follows:
Consistency of performance is poor. Specific performance data, poor repeatability and consistency. Our induction meter automated production level is not high, most still manually processing methods mainly due to the involvement of the production process in manual too, is difficult to guarantee a high degree of consistency of product performance, but also increased the difficulty of production management.
Material quality problems are not resolved. Induction meter to measure the lifetime guarantee accurate and reliable, must ensure that the structure of the long-term stability, the key energy meter parts have enough ability to adapt to a variety of harsh environment, which requires induction meter of the rotating element adequate wear characteristics, magnetic materials have magnetic properties and other long-term stability requirements. As the materials industry in China and the developed countries there is still a wide gap, a company how to detect, the choice of key components (such as magnetic thrust bearing, the damping magnet, etc.), is currently the issues to be addressed.
The key technology is not resolved. In addition to a more comprehensive selection of qualified design and materials, induction meter to achieve long life must also have reliable processes. Coil winding, core punching rivet system, the production of graphite bearings, magnetic thrust bearing is also a need to address aging issues.
(2) Electronic form
The display. Meter display is an important component, the original use of mechanical counter and when the counter and there is a certain percentage of cards of words and the probability of dislocation, and higher in the anti-tampering, its weakness against magnetic interference are more vulnerable to poor illegal users of the attack, although the increase in non-return device can be used to prevent the reverse, increasing the thickness of the motor shield reduced the magnetic field disturbances, but can not fundamentally solve the problem. LCD and resolves the above problems, but some manufacturers use the LCD display quality varies, especially in the ultraviolet radiation, high temperature and high humidity, low temperatures prone to problems.
Software reliability. Electronic energy meter is a distinctive feature of the hardware manufacturers to use more and more close, and more and more features through software to achieve, so the reliability of the software largely determines the reliability of the meter itself. The quality of the hardware itself can be based on technical parameters and indicators, and through the associated experiments to verify its reliability, performance and quality, and reliability of the software is no good in the final product means you can quickly check out the normal various test cases, software may be running normally, but in some interference or unusual circumstances, if the software for these ill-considered, will be prone to problems.
Communication protocol. At present, the electronic energy meter regardless of communication interface, generally following the DL / T 645-1997 “multi-function meter communication protocol.” With the power sector continues to develop modern management, the existing DL / T 645 of the Statute has been in many respects, the meter can not meet the functional requirements, manufacturers need the new features are on the DL / T 645 extends the statute, but all manufacturers are mutually incompatible, there is no unified record management; the local power sector due to the local needs of the sector and the development of modern management, but also on the DL / T 645 extends the statute, and will be updated from time to time. Because of the lack of a unified communication protocol planning and management, the current communication protocol has been very confusing, leading to both the use of DL / T 645 of the Statute of the various manufacturers of the meter can not be interconnected in the same area at different times of the meter can not interoperability, coupled with various meter manufacturer, acquisition device manufacturers, software providers on the DL / T 645 is also biased understanding of the statute, may also lead to “even with the same communication protocol can not be interconnected” to happen.
Harmonic measurement. When the power source line with the presence of harmonics, harmonic power load will cause the non-linear waveform distortion. Harmonic case, the user side of the energy can be divided into fundamental input power, harmonic input power and harmonic output power, and linear load user should only be consumed by the fundamental input power, should not be included in the harmonic input power, users more pay; when the load is nonlinear, the load usually produces harmonic output power, then the user will also generate pollution but less pay. Currently, some manufacturers use DSP technology in addition to its own energy metering algorithm under accurate measurement of harmonics, the most dedicated digital multiplier chip can measure accurate measurement of harmonics user. This is usually measured in the residential customers there is no problem, but in the harmonic generation on a larger industrial metering will bring a greater injustice.
Multi-function table definitions. With the continuous development of multi-table technology, the electricity sector for multi-user functional requirements of the table more and more, in addition to the more standard variety of measurement data and reference variables, raised more information about power quality detection functional requirements, such as the quality of light there is for the off-phase voltage, overvoltage, undervoltage, loss of pressure, total loss of pressure, voltage unbalance, voltage distortion, voltage qualification rate, but many of these features is not clearly defined, or individual users have different definitions, resulting in a function the same for different users to different changes, if not as soon as possible to develop standards for uniform definition of multi-table feature will result in more and more confusing, is not conducive to multi-table technological progress.
The reliability of power line carrier technology. As the low-voltage distribution network of the most extensive coverage throughout every corner of every household, where there had stretches where the meter network, so residents of automatic meter reading is the most convenient and most economical communication channel, and no monthly fees. However, due to the complex structure of low-voltage power grid network, lack of planning, grid serious pollution and other reasons, resulting in a power line carrier signal attenuation is very serious, very large signal to noise ratio down the situation, although the PLC technology has made significant progress, the communication was successful rate has increased, and in some places of the pilot countries have relatively small ideal, but in large scale in carrier reliability of the technology to be further verified.
Energy meter industry technology trends and focus.
4, a comprehensive alternative to electronic energy meter sensor table
Electronic energy meter is able to replace the sensor table and become the darling of the market, has many advantages: ① reliability: accuracy for a long time constant, no round school, no installation, transportation impacts; ② Accuracy: Wide range, wide power factor, start-sensitive, anti-submarine and reliable; ③ Function: centralized meter reading, multi-rate, pre-paid, anti-tampering, multi-functional; ④ cost: cost-effective, can be reserved for extensions, up by raw materials price impact on small and so on.
Further enhance the performance measurement
With the electronic energy
The basis of rural power grid is very fragile, and the line erected not standardized, the phenomenon is more common, there are serious security risks, many rural consumers, the lack of electricity knowledge, a poor sense of security, the use of counterfeit electrical equipment and private pull random access phenomena prominent, easily lead to useelectrical safety incidents.
