This mode is used to measure AC single-phase active energy with a rated frequency of 50 Hz, and realizes the management function of paying first and then using electricity. Adopt advanced microelectronic technology for data collection, processing and storage, and use radio frequency card to transmit data.
Common pre-stored methods
There are two pre-storage methods, one is code type and the other is write card type.
The code principle is: the management system combines user information and electricity purchase information to generate a set of encrypted codes, which are given to the user to input into the electricity meter. After the electricity meter is correctly decrypted, the pre-stored electricity or amount is obtained and saved.
Card writing: write the pre-purchased power or amount into a special electronic card (memory), and give the user the electronic card to communicate with the corresponding meter, and the pre-purchased value is automatically sent to the meter.
Electronic cards, or IC cards, or electricity purchase cards, are all made of special IC chips after special packaging. Common electricity purchase cards are divided into contact and non-contact types according to communication methods.
Contact types include: card cards and key cards, and non-contact types include: radio frequency cards and remote control cards.
working principle
The electric energy meter is composed of two main functions: one is the electric energy metering part, which uses a dedicated integrated energy metering chip to calculate the sampling signals of voltage and current, and generates metering pulses representing electric energy directly used for electric energy error verification, and at the same time to the MCU The functional processing part of the computer performs energy counting; the second is the microprocessor MCU control part, which calculates the electric energy according to the electric energy pulse of the metering part, and exchanges data through the radio frequency card interface. At the same time, it uses a wide temperature range LCD to display and press the setting The parameter-controlled magnetic holding relay controls the user's power consumption.
Features
1. Features of prepaid watt-hour meter:
1. Using large-scale integrated circuit and SMT processing technology to ensure the high reliability of the product
2. The electric energy meter has low power consumption, far less than the national standard requirement
Voltage line: ≤0.7W and 4VA (National standard: ≤2W and 10VA)
Current line: ≤0.3VA (national standard: ≤4.0VA)
3. Strong anti-stealing function. The single-phase electronic watt-hour meter produced by our company adopts advanced anti-stealing technology. It not only has ordinary electricity theft methods such as preventing the meter from tilting, applying a magnetic field, short-circuiting, and reverse power consumption, but also has the function of preventing electricity theft from one fire to one place.
4. In terms of structure, it is designed with an anti-theft end cover to prevent short-circuiting
5. The range of the watt-hour meter is wide, and the overload multiple is guaranteed to be more than 6 times
6. The watt-hour meter has an anti-creeping logic circuit, and 125% of the voltage is applied, and the watt-hour meter has no test pulse output
7. When the watt-hour meter is at 0.4% Ib, the watt-hour meter can start and record
8. The watt-hour meter has a wide working voltage range: when 380VAC is incorrectly applied for a long time, the watt-hour meter can still work normally
2. Prepaid watt-hour meter function:
1. Automatically cut off the power after using the purchased electricity
2. Load control can be selected, overload delay power-off
3. Alarm for insufficient remaining battery to remind users to purchase electricity in time
4. The LCD screen has obvious electricity consumption information, which is convenient for users to view
5. The LCD screen displays the accumulated power and remaining power at the same time clearly and intuitively
6. The ISO standard IC card adopts a special data dynamic encryption algorithm, which is safe and reliable, with one meter and one card
7. Large-capacity meter reading card, complete and accurate meter reading
8. The electricity purchase card will automatically copy back electricity usage information to facilitate management and verify user information
9. Dedicated setting card and meter replacement card to facilitate the registration and maintenance of the management department
10. Adopt power-off processing technology to ensure that data will not be lost for 30 years after power-off
market expectation
The demand of power system management departments for prepaid watt-hour meters is showing a diversified development trend. The following are a variety of prepaid watt-hour meters that are commonly required by current power system management departments and specific users:
(1) Three-phase prepaid watt-hour meters suitable for small and medium-sized power users/commercial households with large liquidity and tendency to arrears.
(2) It is suitable to solve the three-phase prepaid watt-hour meter with one meter and multiple cards used in irrigated land by multiple peasant families.
(3) Suitable for three-phase multi-rate prepaid watt-hour meters with tariff and time usage needs.
(4) Single-phase payment rate prepaid watt-hour meter suitable for implementation of residential time-of-use tariff policy
(5) Single-phase prepaid watt-hour meters suitable for ordinary residents
State of development
Before 1995, mainly electric key IC cards, with 93C46 and 24C01 as the main IC cards as rewritable memory chips (EEPROM) or general memory cards. IC cards are easy to store, easy to use, inexpensive, and have low security. The possibility of being cracked, users are mainly the property community.
From 1995 to 1999, it was mainly telephone card IC card, with memory card (24C01) and logical encryption card (4442, 4428) as the main ones. The security of logical encryption card (4442, 4428) was further improved, and the embedded chip was The control logic is added outside the storage area, and the password needs to be checked before accessing the storage area. Only when the password is correct can the operation be performed. Users have expanded from a simple property community to the management department of the electric power industry, and they have begun to be widely used on a large scale.
From 1998 to now, mainly financial-grade IC cards, with CPU card (CPU card and SAM module as encryption media) as the main CPU card embedded chip is equivalent to a special type of single-chip microcomputer, except for the internal controller, memory, timing In addition to the control logic, it also has an algorithm unit and an operating system, with large storage capacity, strong processing capability, and information storage security. Take the lead in comprehensive promotion in Beijing Power Supply Bureau, and began to promote in Henan, Hunan and other cities.
Prepaid watt-hour meters have brought great convenience and benefits to the charging and meter reading of the electric power department, and also brought profits to manufacturers; as IC card prepaid watt-hour meters manufacturers should fully learn from the case. The many thoughts that come, actively carry out self-reflection, prevent micro-faults, and actively eliminate problematic products, so as to be responsible for the company itself, for the development of the industry, and for the society! Work together to maintain the healthy development of the watt-hour meter industry!
How to install and use
When installing the prepaid meter, the installation position should be kept vertical and connected according to the wiring diagram.
4.1 Open the cover of the terminal button box of the electric energy meter, then connect the terminal button wiring according to the wiring diagram, and turn on the power.
4.2 The user inserts the pre-purchased power IC card into the meter in the direction of the arrow on the card (the metal contacts face to the left), the display first displays F1, then displays the current purchased power, then stably displays F2, and then the display displays the original remaining power plus the new purchased power The sum is the current remaining power. At this time, the IC card can be removed and the display goes out. (For example, when the remaining power in the meter is lower than the displayed alarm power, the display is always on, and when the sum of the original remaining power in the meter and the power in the power purchase card is greater than 9999kWh, the power in the card is not entered into the meter and is still stored in the card.)
4.3 When the user uses electricity, the pulse indicator will flash.
4.4 During the normal use of the prepaid electricity meter, the purchased electricity will be automatically decremented. When the remaining power in the electric energy meter is less than 20 degrees, the display shows the current remaining power to remind users to purchase electricity. When the remaining power is equal to 10 degrees, a power failure reminds the user to purchase electricity. At this time, the user needs to insert the IC card into the energy meter once to restore power. When the remaining power is zero, the power supply is stopped.
4.5 One meter, one card, after each new purchase of electricity, the user can only insert his own meter to input the effective electricity once.
4.6 The display of the prepaid electricity meter usually does not light up. If the user needs to check the remaining power, insert the IC card into the meter, and the F1 purchase power display shows zero, F2 the remaining power display, and the card removal display goes out.
4.7 Every time the user inserts the IC card into the prepaid meter, the meter will fill in the user's electricity consumption on the IC card. When the user purchases electricity next time, the sales management system will read the IC card data summary and check whether the user is legally using electricity . Electricity inspectors can also use the inspection card to check the electricity consumption of users.
4.8 The power supply management department sets the user's maximum power load according to the actual situation. When the actual power load exceeds the set value, the power supply will be stopped and the meter display will display "E2" to remind the user to reduce the power load. The user needs to insert the IC card into the meter and restore the power supply.