Design and application of remote prepaid system for smart energy meter
The power system uses smart energy meters to realize remote centralized reading. The principle is to use remote intelligent meter reading tools to collect and analyze user data, and then use the data communication transmission function to transmit the data collected from users to the management platform. Collecting user data is the basic information to realize intelligent electricity consumption. The development of automatic electric energy meter reading technology is the only way to realize intelligent electricity consumption and electricity management, and it is also an inevitable product of the development of power system and intelligent digital life.
1 The main methods of remote collection of electricity data
1.1 RS485 communication method
1.2 Narrowband power line carrier communication method
1.3 Broadband Power Line Carrier Communication Mode
1.4 Micro power wireless communication method
2 Realization of remote centralized reading system of smart energy meter
The structure of the remote centralized reading system consists of an upper computer and a lower computer. The upper computer includes a central management station, and the lower computer includes a data concentrator and a collection terminal. The role of the host computer has two aspects, one is responsible for setting the system, sending commands, monitoring and displaying system status, and the other is maintaining two-way communication with the data concentrator. The data concentrator is the communication hub of the whole system and has a very important position, not only to receive instructions, centralized and statistical data, but also to connect smart meters and central stations. The collection terminal is connected to the smart meter, and is mainly responsible for the data collection and recording of the user’s real-time electricity consumption. Not only that, but also the related parameters of the meter can be set and data forwarding can be realized. Therefore, the data concentrator needs to communicate with the central station and the smart meter at the same time. The system uses the concentrator tool to transmit the communication data with the central station in the form of GPRS, and then the short-range communication with the smart meter uses wireless communication., it can be seen that the concentrator itself needs a module for wireless communication.
3 Basic requirements for smart meter design
In order to realize remote centralized reading, the overall requirements for the design of smart meters mainly rely on three different units, and the corresponding functions are energy collection, signal processing and data communication. Generally speaking, smart meters have the following major functions:
(1) Input and output function This kind of meter needs to display data, usually with the help of LCD display screen. The display of this kind of electricity meter displays many contents, such as the operation status of the equipment, the year, month, day, time, peak and valley values of electricity consumption, and circular display of the average value of electricity. In addition, this kind of electricity meter also has many functions in terms of information input, such as start, pause, confirm and so on.
(2) Data storage The smart meter uses a secondary storage system for data storage. The first level is implemented by the program memory flash memory of the CPU, and the second level is implemented by the extended flash memory.
(3) Meter reading If you want the meter data to be transmitted more smoothly, the infinite module SI4438 can achieve this purpose. Of course, in addition to this, RS485 interface can also be used to summarize the data to be transmitted into the concentrator, and then use the wireless network to perform remote automatic meter reading for these data. If you have doubts about some data, you can also use the terminal to read the meter on the spot.
(4) Communication There are two main communication methods for smart energy meters, one is through the Si4438 wireless module, and the other is through the RS485 interface. The communication function of the latter is more powerful and flexible, and the distance between 1.2 kilometers can meet the needs of users. More importantly, this method can be interconnected with the currently mainly used handheld meter reading terminal equipment, making meter reading easier.
(5) Programming After programming is adopted, the use of related functions of the meter will become more flexible. When designing the scheme, wireless radio frequency technology can be used for the data transmission method of the entire system, so that the commands sent by the host computer are transmitted to the RS485 interface through the data concentrator, and then the entire meter can be programmed and controlled.