What Are Electric Meters?

The abbreviation of electric energy meter is a meter used to measure electric energy, also known as electric energy meter, fire meter, electric energy meter, kilowatt hour meter, and refers to a meter that measures various electrical quantities.

The earliest watt-hour meters (also called watt-hour meters) were made according to the principle of electrolysis in 1881. Although this kind of watt-hour meters each weighed tens of kilograms, they were very bulky and there was no guarantee of accuracy, but they were still used as scientific A major invention was valued and praised by people, and it was quickly adopted in engineering. With the development of science and technology, the discovery and application of alternating current in 1888 put forward new requirements for the development of electric energy meters. After the efforts of scientists, inductive energy meters were born. Since the inductive energy meter has a series of advantages such as simple structure, safe operation, low price, durability, and easy maintenance and mass production, it has developed rapidly.

China's AC inductive energy meters were produced from imitations of foreign energy meters in the 1950s. After more than 20 years of hard work, China's energy meter manufacturing has reached a considerable level and scale. With the development of science and technology, and Requirements for overload capacity and service life of AC inductive energy meters. In the 1980s and 1990s, China began to implement long-life energy meters, mechatronic energy meters (semi-electronic energy meters), all-electronic energy meters, multifunctional all-electronic energy meters, prepaid energy meters, and multi-rate energy. The development and production of meters, maximum demand meters, loss energy meters, etc. Since 2000, these semi-intelligent energy meters have been widely used in household electricity, commercial electricity and other aspects.

In 2009, after the British government applied the first batch of meters with network communication functions to household electricity for the first time, the State Grid of China immediately proposed the concept of "smart meters" in the country: 26 grid province companies under the State Grid Corporation of China In the second half of 2009, the unified technical standards were formulated. At this time, it was in the context of the state grid company to build a smart grid. Therefore, the energy meters to be purchased in the future are collectively referred to as smart meters. The main thing is to solve the problems of ladder electricity prices and remote meter reading. Of course, there are still some functions to be expanded in the future. In fact, the functions of smart meters have been reflected in the original semi-intelligent energy meters, which is nothing more than the national grid and the network communication and optoelectronic communication functions, issued in the form of industry standards.

The main types of smart meters are IC card meters. The user holds the IC card and pays power to the power supply department. The power supply department uses the power management machine to write the purchased power into the IC card. The user holds the IC card to brush the non-contact IC in the induction area. Card (referred to as "swipe card", the same below), you can switch on the power supply, and remove the card after power supply. When the remaining power in the table is equal to the alarm power, the power failure alarm (or buzzer alarm) is triggered. At this time, the user can restore the power supply by swiping the card in the sensing area; when the remaining power is zero, the power is automatically turned off and the user must Once the card is paid again to purchase electricity, electricity can be resumed. For residents' electricity, when compared with mechanical meters and electronic meters, it has the following advantages:

1. With a variety of anti-theft functions, small starting current, no creep, wide load, low power consumption, straight error curve, good stability during long-term operation. Single-phase Local Charge Control Smart Meter

2, beautiful appearance, small size, light weight, easy installation.

3. High accuracy: Fully electronic design, built-in imported special chip, accuracy is not affected by frequency, temperature, voltage, and higher harmonics.

4, long life: SMT technology, optimized circuit design, the whole machine does not need to adjust the circuit after leaving the factory.

5. Low power consumption: Low power consumption design is adopted to reduce grid line loss.

6. Pre-purchased power; IC card passes data to realize data readback, including: read back total power, remaining power, accumulated power purchase in the table, total number of power purchases and other information.

7. Store table constant, initial value, user address, name and other information.

8, overload alarm power failure, residual power alarm, remind users to purchase power in a timely manner.

The emergence of smart meters has also brought a lot of benefits to the energy meter detection mechanism. For example, in the past, when testing a mechanical or electronic meter, after installing the meter on the energy meter detection device, the debugger needs to manually enter the address of each meter in the debugging software, as well as the active and reactive power levels of the meter, and the application of the meter. These commissioning parameter schemes greatly increase the workload of the commissioning staff, delay the delivery of the energy meter on time, and have a significant impact on the brand image of the enterprise. However, since the birth of the smart meter, the commissioning staff only needs to Machine, then connect the network cable port of the debugging computer to the network port on the energy meter verification device, set the communication serial port between the PC and the device, and then automatically generate their various parameters on the verification software. In the process, whether the quality of the smart meter meets the national standard can be clearly seen on the computer display. ^[1]

The ammeter can be converted into a voltmeter, a current meter with a larger range, or

Supplier: Electric meter, IC card electric meter and other related products.

According to the national standard GB / T15283-94 and the international standard IEC521-1988, the energy meter is marked with two current values, such as 10A. The 10A marked here is the basic current, the symbol is the current value that determines the relevant characteristics of the instrument. This current value is also called the calibration current. A in parentheses is

Rated maximum current (rated maximum current), symbol, is the maximum current value that the meter can meet the accuracy specified by the standard. The current through the energy meter can be as high as 2 to 8 times the basic current, and less than 2 times the basic current value on the meter. In other words, if the energy meter installed by a user is only marked with a current value, such as 5A, this is only the basic current value, not the maximum allowed current. This kind of energy meter can generally be overloaded to 120% without problems, and it can meet the accurate measurement of the energy meter. On the other hand, due to the large resistance of the rotating mechanism of the induction energy meter, according to the standard, the starting current cannot be lower than 0.5% of the basic current (energy meter with accuracy level). It may fail to start at 0.5% or less.

In China, the voltage of the domestic residential power supply line is 220V and the frequency is 50Hz. The rated voltage and applicable frequency of the selected energy meter should be consistent with this line voltage and frequency, and should also be 220V, 50Hz.

When choosing an energy meter, the choice of current value is the most important and the most complicated. One is the starting current, which is the minimum current that enables the turntable to continuously rotate; the other is the multiple of the maximum rated current relative to the basic current. In addition, there are differences in performance between old-fashioned and new-style watches. The old electric energy meters that are still used in old houses have relatively large starting currents, generally (5% to 10%); the maximum rated current is small, generally 2, and only one current value is marked on the dial surface, and it is generally called Rated current. Therefore, it is pointed out in the old electrician's manual that the current of the load circuit should be greater than 10%, less than 120% or less than 125% of the rated current when in use. According to the national standard GB / T15283-94 and the international standard IEC521-1988, the starting current of the energy meter used in the newly built house is small, which is 0.5% for the meter; 2 ~ 4), some reach (6 ~ 8). There are two current values on the face of the new electric energy meter dial, such as 5 (20A). When selecting this electric energy meter, on the one hand, pay attention that the minimum current of the load cannot be lower than the starting current, that is, 0.5% × 5A = 0.025A; On the other hand, the value of the ammeter used for a long time cannot be higher than the maximum rated current of 20A. When choosing an electric energy meter, it should be taken into consideration that an increasing number of electrical appliances enter the home, and a margin must be left, and it should be reasonably appropriate, because the greater the multiple, the higher the price of the meter.

The current value 10 before the brackets is called the calibration current, which is used to calculate the load base current value. The current 20 in the brackets is the rated maximum current. It is the maximum current that can make the energy meter work normally for a long time, and the error and temperature rise fully meet the requirements value. According to the requirements of the regulations, the calibration current of direct-connected energy meters should be determined according to the rated maximum current and overload multiples. Among them, the rated maximum current should be determined according to the approved load capacity of the customer; the overload multiple, for normal operation If the actual load current of the electric energy meter in China reaches more than 30% of the maximum rated current, a double meter should be taken; if the actual load current is less than 30%, a 4 times meter should be taken.