China's Modern Grid Measurement Technology Platform
Chunhui Zhang
June 21, 2018
1) IEEE1901.1 International Standard
Online Report:CECC Releases "IEEE1901.1 International Standard"
- On May 22, 2018, IEEE1901.1 "Technical Standard for Medium Frequency (below 12MHz) Power Line Carrier Communications for Smart Grid Applications" jointly developed by CECS, State Grid ICT Industry Group and other enterprises was formally released and implemented.
-The standard is based on State Grid's Q/GDW 11612 "Technical Specification for Low-Voltage Power Line Broadband Carrier Communication Interconnection and Interoperability," and makes extensive use of innovative technologies to propose physical layer communication specifications centered on OFDM, dual binary Turbo coding, and time-frequency diversity copying, and data link layer communication specifications represented by channel timing optimization, tree networking, and multi-table area network coordination, and data link layer communication specifications represented by channel optimization, tree networking, and multi-table area network coordination. coordination as representative of the data link layer technical specifications.
The release of this standard fills the gap of international standard for medium frequency power line carrier communication application in the field of smart grid, and enhances China's international influence and voice in the field of Internet of Things.
- The IEEE1901.1 standard realizes the effective application of Internet of Things (IoT) technology based on power line carrier communication in the energy Internet by constructing a high-bandwidth, high-reliability, low-latency, and low-cost power line communication network to support multiple application scenarios such as remote automatic meter reading and power distribution station monitoring.
The standard will promote the development of the entire industry of power line carrier communication chips, communication modules and smart terminals.
2) State Grid, broadband (IF) power line carrier communication technology development process
Why does State Grid emphasize the development of broadband (IF) power line carrier communication technology?
State Grid's power consumption information collection system construction, starting in 2010, was basically completed in 2017, with 430 million households, 99% coverage, for power consumption information collection equipment and user engineering investment in huge amounts, about 51 billion yuan. Among them, 70% of the local communication methods use narrowband (low-speed) power line carrier communication technology. After years of operation, the communication rate of narrowband (low-speed) carrier communication method is slow, the success rate of automatic collection is low, and some single-phase meters in residential neighborhoods can't be copied for 24h, which has become the technical bottleneck of local communication, and it is difficult to be solved for a while. As a result, the State Grid has taken advantage of the resources of the distribution network's household power lines, and has made the practical application of broadband (intermediate frequency) power line carrier communication a key development issue for new communication technologies.
According to the prediction of distribution and power management communication flow put forward by the experts of China Electricity Academy of Sciences (CEA), the broadband (medium frequency) carrier communication rate needs to meet the following requirements of power information collection:
- Communication rate of AMR/AMI: 1.2/20 k bps
- Load management: 10 k bps
- Expansion of the power distribution business, distribution automation, alarm management, and DG are the key issues in the development of new communication technologies. automation, alarm management, and DG all at 10 k bps;
-Distribution video monitoring requirements at 1 M bps; other video communication requirements newly proposed by distribution.
- In July 2012, the State Grid's "New Generation of Intelligent Power Line Carrier Communication Key Technology Research" project was launched. The intelligent PLC is a carrier communication technology with cross-band (150 k Hz - 10 M Hz), frequency self-awareness, self-adaptation, self-organization, and coordinated communication functions.
The project is led by the China Academy of Electric Sciences, with the participation of State Grid Communications Corporation (SGCC) and Nanrui Group.
In November 2014, the project passed acceptance. Its intelligent PLC system has carried out practical testing and verification on medium and low-voltage power lines in Shaoxing and Changchun power grids.
- In July 2014, at the technical exchange meeting on the topic of "Research on the Full Performance of Imported High-end Electric Energy" (Changsha:Wisepac) organized by the author of this paper, Huawei Haisi introduced its independently designed Hi3911 type broadband (IF) carrier chip with frequency band:2--12MHz,communication rate 200k--14M bps.
From this estimate: Huawei Haisi's IF carrier chip launch time is more like a little earlier.
- In October 2014, the State Grid held a seminar on low-voltage power line broadband carrier communication technology standards, proposed broadband carrier communication unit technical specifications, inspection specifications, communication protocols (preliminary draft).
- In November 2014, in the power line carrier communication new standards, new products (Qingdao:Neusoft) technical exchange meeting organized by the author of this paper, focusing on the exchange of international/domestic broadband and OFDM narrowband carrier communication new technology.
- In 2015, it is understood that Huawei Hesse will (IF carrier chip) physical layer and communication protocols in the State Grid broadband carrier communication technology enterprise standards for **** enjoy. Each broadband carrier chip manufacturers in the chip physical layer uniform premise, independent development of broadband carrier products.
- In 2016, at a seminar on current hot issues in the development of the meter industry (Chongqing Huali) organized by the authors of this paper, the Chongqing Municipal Academy of Electrical Sciences presented the results of the on-site broadband carrier communication interconnection and interoperability test in a large-scale public transformer substation area (about 700 households).
- In 2017, Jiangsu ECS completed the interconnection test of broadband carrier modules, verifying the interconnection of broadband carrier modules under complex operating conditions in the field, such as overhead lines, pre-buried cables, urban and rural areas.
- In 2017, Chongqing University of Posts and Telecommunications, Chongqing Municipal Academy of Electrical Sciences, "System Generator-based Wideband Powerline Impulse Noise Realization Methods" proposed:Realization of Class A noise generator based on FPGA will be conducive to the assessment of anti-noise performance test of broadband PLC products.
- In 2017, the State Grid released:Technical Specification for Low-Voltage Power Line Wideband Carrier Communication Interconnection and Interoperability (Q/GDW 11612--2016)
It is understood that the standard is divided into six parts:
Part 1:General Provisions
Part 2:Technical Requirements
Part 3:Test Methods
Part 4:Technical Requirements
The standard is divided into six parts. Part 3:Test Methods
Part 4:Physical Layer and Communication Protocols
Part 5:Link Layer and Communication Protocols
Part 6:Technical Requirements for Application Layer
- In May 2018, CECC published:Intermediate Frequency (below 12MHz) Power Line for Smart Grid Applications. Carrier Communication Technology Standard (IEEE1901.1)"
3) Qingdao Neusoft:Launched a broadband (IF) carrier communication chip that complies with the IEEE1901.1 international standard and obtained an international license
Online report:
"IEEE releases a new standard for carriers, Neusoft's carrier chip obtains international license "
-Eastsoft launched a new carrier (IF) chip model:
Eastsoft SSC1667. now, there are at least 1 million chips in use in the network, and continue to deepen the application, with super capacitor power outage reporting station automatic identification and other functions.
-Eastsoft SSC1667 broadband (IF) carrier communication chip design performance
- 40nm Flash process, SOC chip integration, Flash built-in, low peripheral cost
- OFDM orthogonal frequency division multiplexing (OFDM) modulation technology
- communication rate of 6MHz
- Communication band 0.7MHz---12MHz
- Lower power consumption: static power consumption 0.7W/dynamic 1W
- Support the new/old national network broadband interconnection standard, support the frequency band switching
- 4 frequency bands, 6 modes, the specific support for the standards and frequency bands: (omitted).
4) Review
- China realizes zero breakthrough in the formulation of international standards for power line carrier communication technology
In the international arena, the intermediate-frequency (less than 12MHz) power line carrier communication technology standard (IEEE1901.1), which is applicable to smart grid applications, is jointly formulated by the Chinese Academy of Electrical Sciences and other units. It fills the gap of international standard for medium frequency power line carrier communication application in the field of smart grid.
After checking:
-Internationally, the development of broadband (high frequency: 2MHz and above) power line carrier communication standards: the focus area of the first research is the smart home network, and later oriented to the home digital multimedia, video, audio, data, energy intelligent control and other communication needs. In this regard, Home Plug (Home Plug) Alliance proposed broadband power line carrier communication technology standards earlier, broad, some of the broadband carrier communication standards, has been converted to IEEE international standards:
From the 2001 Home Plug 1.0 standard, the data rate of up to 14M bps, mainly located in the home network applications, but also for low-voltage Broadband access; Home Plug 1.0 --- Turbo standard in 2004, to enhance the data rate, the maximum data rate of 85M bps,; Home Plug AV standard in 2005, the band: 1.8 --- 25MHz, the maximum data rate of 200M bps, for the transmission of video, audio, data; Home Plug Green PHY standard in 2006, is for the home networking applications, the maximum data rate of 14M bps. Green PHY standard, designed for embedded smart energy and automation applications in homes and buildings, is interoperable with IEEE1901/Home Plug AV standard powerline network protocols and has features such as reduced data rate from 200M bps to a lower rate (note: 10M bps), low power consumption (note: 80% reduction in power consumption), low cost and wide home coverage. capabilities, among other features.
-International narrowband (low frequency: 500kHz and below) OFDM power line carrier communication standards:
In 2009, MAXIM released the G3 standard
In 2011, the PRIME Consortium was established, and released the G3-PLC standard; ITU (International Telecommunication Union) G9955 is compatible with the G3-PLC physical layer; IEEE G3-PLC is compatible with the G3-PLC physical layer; and IEEE G955 is compatible with the G3-PLC physical layer; and the G3-PLC is compatible with the G3-PLC physical layer. ---PLC physical layer; IEEE P 1901.2 is compatible with G3---PLC physical layer
2012, G3---PLC update released by ITUG9903; updated version released in October
2013, ITUG9903 releases updated version; IEEE 1901.2 voted to become official
< p>In 2014, ITU G9903 was released as a further update.These narrow-band communication standards, using OFDM low-frequency narrow-band carrier communication technology, with higher transmission rates and frequency bands have the advantage of flexibility and other advantages and rapid rise, mainly used for automatic meter reading management, smart home network, frequency band: 10k - 500k Hz , data transmission rate 20k - 150k bps.
-The above situation describes:
a1 Internationally, for a long time, the intermediate frequency (150k--12MHz) power line carrier communication method applicable to smart grid power consumption information collection has not been introduced into the international standard.
a2 Domestically, since 2009, after the State Grid proposed to carry out the construction of power user electricity information collection system, it has been carrying out multi-faceted cooperative research on medium frequency (less than 12MHz) power line carrier communication technology applicable to smart grid applications.
The proposal of IEEE1901.1 international standard is based on the results of the multifaceted cooperation and innovation and systematic research on the development of IF carrier chip for broadband (intermediate-frequency) power line carrier communication, on-site interference performance test for broadband carrier communication, discussion on interconnection and interconnection of broadband carrier communication, and formulation of standards for broadband carrier communication in the domestic market.
-From the application point of view, what are the technical difficulties and controversies in IF (below 12MHz) power line carrier communication?
Internationally, the delay in launching the international standard for intermediate frequency (less than 12MHz) power line carrier communications for smart grid applications is estimated to be mainly due to application technical difficulties and controversies.
After synthesizing the new standard/new product technology exchange meeting in Qingdao in 2014, and discussing the hot issues in the development of Chongqing meter industry in 2016, the author of this paper puts forward three difficulties and controversies in the development of IF power line carrier communication application technology:
One of them is the bi-directional high-frequency interference of IF power line carrier communication. In June 2013, ITU--R (International Telecommunication Union Radiocommunication Sector) released "Impact of Power Line Communication Systems on Radiocommunication Systems Operating Below 80 MHz (ITU--R SM.2158--3 Report)", which questioned the power line carrier communication method.
Note:SM Series, Spectrum Management.
(Note:We have not yet seen the comments on ITU--R SM.2158--3 report from the domestic authorities)
The second one is the assessment of the severity of the impact of the pre--embedded cables and reactive power compensation devices of the distribution network on the intermediate frequency power line carrier communication and the reasonableness of the improvement measures. As measured in the field, sometimes when the concentrator is arranged before the
reactive power compensation device (power side), the success rate of automatic meter reading is very low or even the meter cannot be read.
Third, the broadband carrier communication interconnection problem. It is understood that in China, the physical layer and communication protocols of IF carrier chips of various broadband carrier chip manufacturers have been unified, but the path selection and relay function of the network are still different, so the interconnection effect is not satisfactory in the actual networking and meter reading in the field.
Aiming at the above difficulties and controversial issues, it is understood that the State Grid metering department unified organization of field test analysis, put forward some improvement measures. But from journals, online rarely see reports in this regard.
This time, the IEEE1901.1 international standard puts forward the physical layer of intermediate frequency (less than 12MHz) power line carrier communication network, data link layer technical specifications, and its large number of innovative technologies used to improve the quality of communication signals (bits, frames) sent and received and data transmission performance. It is understood that the country then has the intention to continue to cooperate in the development of medium frequency carrier communication network network network layer and other layers of technical specifications, expects in networking technology, routing algorithms, data transmission, interconnection and other deep communication technology development and unification, to achieve a substantial increase in the rate of electricity information collection, automatic collection success rate, to solve the application of medium-frequency carrier communication quality of the application of the problem caused by the quality of the problem.
At the same time, the authors of this paper propose that there is still a need to cooperate in the research and development of another important standard: the intermediate frequency power line carrier communication channel monitoring, management technical specifications. This technical specification is described in part 5 of this paper.
Mid-frequency power line carrier communication of high quality, only from the mid-frequency carrier communication network technology performance development and channel monitoring and management of the two aspects of the combination of measures, in order to better solve the mid-frequency power line carrier communication application of the three problems.
-Carrier module price. Compared with the narrowband (low-speed) carrier module, the current IF carrier module price is still high, which will affect its large-scale popularization and application. However, it can be expected that as the application volume of IF carrier modules continues to grow, its price can be reduced to a reasonable level.
-Expanding the carrier module update funding channels
2010 - 2017, the State Grid power information collection equipment bidding volume:Concentrator about 4.64 million units, collector about 51.15 million units. If 70% of the narrowband carrier module of the concentrator and collector is updated to medium frequency carrier module, according to the current price estimation of the medium frequency carrier module, the new module of the concentrator will invest 650 million yuan, the new module of the collector will invest 2.5 billion yuan, and the new module of the single-phase carrier meter (estimated at 15% of the 457 million households of the State Grid's power supply service area) will invest 3.4 billion yuan. Totaling the above three items, the State Grid needs to invest 6.55 billion yuan in adopting the medium frequency carrier module. According to the eight-year rotation cycle of traditional electronic meters, the annual need for carrier module renewal funds of 820 million yuan.
By the end of 2017, the construction of the State Grid's electricity consumption information collection system was basically completed. Now to apply to carry out the electricity consumption information collection carrier module update funds to solve the local communication technology bottleneck, whether this funding channel can go through, it is difficult to predict. State Grid, the focus of the current investment or extra-high voltage project and promote the intelligent construction of distribution networks.
Currently, the active fault alarm and repair of residential electricity low-voltage grid, power quality monitoring and control, distribution network and the development of practical interactive functions between users, is the State Grid to promote the construction of intelligent power distribution network short board. As a result, through all levels of power grid distribution management department to put forward the requirements: expand the power information collection system distribution with new functions, apply for medium frequency carrier module purchase funds, is another reasonable channel.
5) Domestically, the intermediate frequency power line carrier communication channel monitoring, management of technical specifications formulated
Internationally, EN50065: "3kHz to 148.5kHz band of low-voltage electrical installations on the transmission of signals":
Part 1: General requirements, frequency bands, and electromagnetic nuisance
Part 2--1. Immunity Requirements for AC Power Communication Equipment and Systems in the 95 kHz to 148.5 kHz Frequency Band for Operation in Residential, Commercial, and Light Industrial Environments
Part 2--2: Immunity Requirements for AC Power Communication Equipment and Systems in the 95 kHz to 148.5 kHz Frequency Band for Operation in Industrial Environments
Part 2---3: Immunity Requirements for AC Power Communication Equipment and Systems in the 3 kHz to 95 kHz Frequency Band for Operation in Electricity Providers
Part 2--2: General Requirements and Electromagnetic Interference. 95 kHz band for AC power communication equipment and systems operated by power providers and distributors
Part 4--1: Low--voltage decoupling filters--General specifications
Part 4--2: Low--voltage decoupling filters--Safety requirements
Part 4---3: Low--voltage decoupling filters--Input filters
Part 4---4: Low--voltage decoupling filters--Safety requirements
Part 4--2: Low--voltage decoupling filters--Input filters
Part 4---3: Low--voltage decoupling filters--Input filters <
Part 4---4: Low-voltage decoupling filters --- Impedance filters
Part 4---5: Low-voltage decoupling filters --- Segmentation filters
Part 4---6: Low-voltage decoupling filters --- Phase couplers
Part 7: Impedances of equipment
Domestic: Medium-frequency power line carrier communication channel Monitoring, management of the development of technical specifications, can refer to the EN60065 series of standards, combined with the characteristics of the intermediate frequency power line carrier communications, need to cover the intermediate frequency band and bidirectional electromagnetic nuisance limits; intermediate frequency carrier signal attenuation and signal-to-noise ratio measurements, concentrator siting surveys; bidirectional high-frequency interference monitoring;
Various types of application environments, the anti-conducted, amplified interference requirements; pre-buried cables, reactive power compensation equipment to the IF carrier communication impact test and processing program; co-frequency interference test and improvement methods; various types of de-root filters; equipment impedance; two-way communication and gateway technical specifications; other requirements.