Smart meter is one of the basic equipment for data acquisition of smart distribution network, which undertakes the task of raw energy data collection, measurement and transmission. It also has intelligent functions such as bidirectional multi-tariff metering function, user-side control function, two-way data communication function with multiple data transmission modes, and anti-theft function.
In order to achieve the above functions, the smart meter is divided into the following parts: 1. Current mutual inductance, voltage division and metering chip constitute the metering part of the meter; LCD or LED and liquid crystal driver chip form the display part; 3. E2PROM and other components realize the storage function of power information; 4. 485, carrier, infrared and other modules are the communication part of the meter. 5. In addition, the smart meter also has the function of timing, so it has its own clock chip, and the general error does not exceed 0.5 seconds a day.
The need for energy storage components in smart meters
Due to the implementation of the tiered electricity price and time-of-use electricity price policy, the frozen electricity error caused by excessive clock deviation will lead to the ladder billing error, which cannot ensure the fairness of residential electricity consumption. During the normal operation of the watt-hour meter, the clock module is driven by the energy provided by the power grid, and during the grid maintenance or power failure, the built-in battery is used for power supply.
The HPLC carrier module of the meter is a new technology, which has great advantages in communication rate and stability performance, which is 7~10 times higher than that of the early communication module. Its high-speed communication mechanism allows it to report power outage fault information within the specified time after the meter is cut off. However, this requires it to have a built-in backup power supply, and the power supply has a high instantaneous power. Therefore, HPLC basically uses 2.7V super-capacitive power supply.
Comparison of overcapacity with commonly used batteries
The high power density of the super-capacitor meter allows it to better perform the task of uploading information after a power outage.
At the same time, the voltage of 5.5V is enough to ensure the operation of the built-in clock, so as to avoid the undervoltage of the rest of the battery and affect the clock system.
The supercapacitance has a long life and is maintenance-free.
The built-in battery that was previously commonly used in common meters often had insufficient voltage, which affected the clock system.
The built-in battery has a shorter operating life and requires maintenance.