Smart meters are the smart terminal of smart grid. To adapt to the use of smart grid and renewable energy, it has the functions of power information storage, bi-direction multiple-tariff measurement, end user control, various data transfer mode of two-way data communication function and anti-tampering function, besides the function of the traditional basic electricity watt-hour meter measuring.
The working principle of smart electricity meter is that electricity meter first generates data: A/D conversion part samples analog signals into digital signals, and then computes and analyzes the power data through the single chip microcomputer in the meter. After that, the data is cached in the cache chip, and the user can read it through the corresponding interface and protocol. According to the use of electricity meters, then different manufacturers will use infrared, wired, wireless, GPRS, Ethernet and other ways to transmit data to the server, so as to achieve remote meter reading.
The current development of China’s smart meter industry is characterized by the modularization, networking, systematization and intelligent by relying on smart grid and modern management concept and utilizing advanced measurement architecture (AMI), efficient control, high-speed communication, rapid storage and other technologies. High reliability, intelligence, high precision, high performance and multi-parameter will become the trend of electric meter technology development.
Modular functions of smart meters
At present, integrated functional design is widely used in electricity meters. The performance of the metering module of the electricity meter is easily affected by the design of other hardware and software, while the metering part of the electricity meter is easily affected by the damage or failure of other functions. Therefore, once the electricity meter fails, the whole meter can only be replaced to ensure the smooth operation of power metering. This is bound to increase the maintenance cost of smart electricity meters, but also cause a serious waste of resources. If the modular design of intelligent electricity meter is realized, only the corresponding fault module can be replaced according to the fault point. This will greatly reduce the daily maintenance costs of the prefectural power companies.
In order to prevent the program of electricity meters from being tampered with and ensure the safety and reliability of the metering function of electricity meters, State Grid Corporation of China does not allow the online software upgrade of electricity meters. With the comprehensive spread of smart electricity meters in China, many problems and demands emerge. In order to solve the old problems and meet the new needs, the State Grid Company can only conduct a new tender by revising the standards. Local municipal companies can only remove all the laid electricity meters and replace them with new ones. This upgrading method not only has a long cycle and high cost, but also causes a large amount of resource waste, which brings great cost pressure and construction pressure to state Grid Company. If the modular design of smart electricity meters is realized, the metering and non-metering parts of electricity meters can be designed into independent functional modules. The upgrading of software and hardware of non-metrological functional modules will not affect the core metrological modules. This not only ensures the safety and reliability of the metering function of electricity meters, but also meets the changing functional requirements of residents in the process of electricity consumption.
The electricity meter will adopt modular structure. It will consist of a base and some more flexible communication components, I/O accessories, control accessories and modules, with customizable functionality. All modules can be replaced and combined to achieve different functional configurations to meet different requirements. In addition, all components and modules can be plugged and played, automatic identification.
Software will also be modular in the future, based on a unified operating system, to ensure that the underlying software architecture of intelligent terminals is consistent, to ensure the consistency of intelligent terminal software.
The modular design of smart electricity meters has the following advantages: First, only by replacing part of the functional modules can the electricity meters be upgraded and replaced without replacing the entire electricity meters, so as to get rid of the defects of batch replacement, elimination and system reconstruction caused by unchangeable in the design of traditional electricity meters; Secondly, due to the modularization of functions and standardization of structure, it is possible to change the power company’s over-dependence on the products of one meter manufacturer, and provide the possibility for the research and development of standardized electricity meters. Third, faulty modules can be replaced by on-site or remote upgrades to improve maintainability and save maintenance costs.
Interface integration for smart meters
The evolution of electricity meters from old mechanical meters to smart meters covers the process of integrating the interface of electricity meters. The smart Grid calls for bidding of tens of millions of watt-hour meter a year. The quantity is huge, involving hundreds of meter factory, chip providers, ports, providers, from R&D to production debugging, and then to installation. If there is no unified standard, it will increase the cost of huge detection, management costs. For power users, the variety of interfaces is bound to affect the user experience and application security. The smart electricity meter with integrated interface realizes the standardization of research and development design, automation of production verification, standardization of warehouse management, unification of implementation and installation, and informatization of payment for copy and reading. In addition, with the promotion of the four-meter collection scheme of water, electricity, gas and heat and the application of the Internet of things technology, intelligent electricity meters with integrated interfaces are the products that adapt to the information age, conform to the characteristics of intelligence and information of intelligent hardware, and meet the market demand of interconnection of all things.
In terms of interface, the base and module will be realized to meet the requirements of automatic interaction and automatic recognition in the future, and the optimization of communication protocol will be realized. Based on it to achieve functional customization, the application software model is required to be unified. Based on this model, different functional modules can be developed to meet different requirements.
The key components of the communication interface converter are modular in design and can support a variety of communication technologies, including carrier communication, micropower wireless, LoRa, ZigBee, and WiFi. In addition, also extended to include the M-bus general interface, 485 communication Bus interfaces. With a large number of modules and ports supporting different communication technologies, the communication rate can be guaranteed and adaptive. In addition, for different communication equipment, the communication module can overload protection and control the carrying capacity. All modules and the base of the device terminal automatically adapt and match, no need to set parameters.
Communication interface converter can support smart meter access of various specifications, which also requires smart meters to be modular and integrated, in order to effectively solve the plug and play requirements.
The modular and integrated design of smart electricity meters will reduce a large amount of waste of resources and reduce the cost pressure and construction pressure of power companies. It will not only reduce the detection cost and management cost of power companies, but also improve the user experience and application security for power users.
Post time: Nov-10-2020