National Grid Single Phase Meter DDS-GW Solution
With the rapid development of electronic energy meter technology, the intelligentization and informationization of power grids has become an inevitable trend. Therefore, smart meters potentially have huge market demand. In order to better build and develop the national grid, the State Grid Corporation of China promulgated a new "Smart Energy Meter Series Standard" in September 2009 to regulate and standardize the development of the power meter industry. The new smart meter standard puts new demands on the design and production of smart meters. The national network single-phase table DDS-GW solution is generated to meet the requirements of the new national network standard.
The national network single-phase table DDS-GW solution uses NXP's low-power LPC1100 series Cortex-M0 microcontroller as the main control chip, which is designed according to the national grid company's smart meter series standard, and meets the "Smart Energy Meter Function Specification". Measurement, local fee control, zero-line anti-stealing, instant / appointment / timing / day freeze, event recording and other functions, with RS485 communication interface and infrared communication interface.
The national network single-phase meter DDS-GW uses NXP's 32-bit Cortex-M0 microcontroller LPC1100 as the main control chip, plus the function unit of metering unit, fee control, RS485, infrared communication, data storage, LCD display and so on. The system structure of the national network single-phase table is shown in the figure below.
High-performance Cortex-M0 processor - tailored to the power industry
The traditional single-phase energy meter solution mainly uses 8-bit single-chip microcomputer as the main control chip, but with the increasing standard of smart energy meter, the traditional solution will be limited in hardware resource utilization and software design. The national network single-phase meter DDS-GW uses NXP's 32-bit LPC1100 series Cortex-M0 microcontroller as the main control chip. The microcontroller is NXP's tailor-made single-phase meter for the power industry. It is based on the Cortex-M0 core, with a clock speed of up to 50MHz, with 3 serial ports, 1 I2C interface, 1 SPI interface and 128K on-chip Flash. Supports three low-power modes: sleep, deep sleep, and deep power down. The LPC1100 series of microcontrollers have rich peripheral resources and high-performance computing processing capabilities, which improve the design flexibility of hardware and software. It is an ideal choice for the single-phase table design of the national network.
Charge control function: RC522 card reader moduleMF RC522 is a low voltage, low cost, small size contactless card reader chip introduced by NXP for "Three Meters" [1] application. It supports ISO/IEC1443 TypeA (communication rate 212kbit/s and 424kbit/s). ) and the MIFARE® communication protocol. The MF RC522 integrates multiple communication interfaces such as SPI, I2C and UART for easy MCU programming control. [1] refers to electricity meters, water meters, and gas meters.
The technical standards are in accordance with the requirements of GB/T 17215.321-2008 "Special requirements for AC measuring equipment - Part 21: Static active energy meters (Grade 1 and 2)". The communication protocol is in accordance with DL/T 645-2007 Electricity meter communication protocol; in line with State Grid Corporation Q/GDW 354-2009, Q/GDW 355-2009, Q/GDW 364-2009, Q/GDW 365-2009 and other series of enterprise standards.
Basic functions and features Energy metering function: metering positive active energy, reverse active energy, combined active energy; time-sharing function: measuring total, sharp, peak, flat, valley electricity; with multi-rate electricity price, ladder price Type of electricity price function; Freeze function: Supports freezing of active power and active power of freezing mode such as instantaneous freezing, timed freezing, hourly freezing, and daily freezing; support time zone table switching, timetable switching, ladder price meter switching; : It has a local fee control function for switching the electric switch to the user. There is an alarm amount and an overdraft threshold amount. When the alarm amount or the overdraft threshold is reached, the energy meter should be able to alert the user by sound, light or other means or control the load switch to interrupt the power supply. When the electric energy meter confirms the renewal of the electricity bill information, the switch can be allowed to resume the power supply; the charge control switch is within the maximum current of 60A for the internal control mode, and the maximum current is 60A or more for the external control mode; the local fee control is implemented by the contactless card, which is State Grid Corporation's safety technical specifications for information exchange; There are a variety of event recording functions: power-down records, programming records, school hours records, open cover records, meter clear records, pull-close records, purchase records, etc. Security and event traceability; Alarm function: support LED, buzzer and LCD display alarm; Display function: The energy meter can display various information on the LCD screen by means of automatic wheel display and manual button display, display information More, rich in content; Password blocking function: Accumulated 3 times password input error, the meter will automatically lock, automatically unlock after 24 hours of password lock; power-off wake-up function: support display button, open watch cover and contactless card insertion and other wake-up methods; With zero line anti-theft function; There are a variety of communication interfaces: RS485, infrared.
The test board DDS-GW V1.00 Demo of the national network single-phase meter is shown in the figure below.
