Electricity is different from other products. First of all, it is invisible and intangible. It cannot be directly determined by human sense organs during use. It must be measured by special equipment. This kind of electric energy metering device specially used for measuring electric energy. In addition, electric energy cannot be stored. Therefore, in the process of electric energy production, transmission, and use, the electric power department needs to install a large number of electric energy metering devices to accurately and timely understand the amount of electric energy in each link.
An electric energy meter is a meter used to measure the electrical energy consumed in a circuit. It is also called an watt-hour meter, a fire meter, an electric energy meter, and a tens of millions of hours meter. It refers to a meter that measures various electrical quantities.
Electric energy meter model representation (refer to the catalog of electric energy meter models published by the National Electrical Instrumentation Standardization Technical Committee)
What's included in the sign of the electric energy meter
A. Name and model (name and model should be officially promulgated by the competent authority);
B. Standard number (according to national standards);
C. Manufacturer name and registered trademark;
D. Product number;
E. Accuracy level (placed in a circle or "CL .XX");
F. Year of manufacture;
G. Unit of measurement (kw, kw·h, kvar, kvar·h);
H. Basic current (indicated by ib) and maximum current (indicated by Imax);
I. The number of phases, lines and reference voltage (V);
J. Reference frequency (Hz);
K. The constant of the electric energy meter;
L. Indicate the recognition or text of the relevant function
In addition to the above problems, it is also necessary to conduct inspections according to customers, and pay attention to whether the signs are printed incorrectly, stained, or unclearly printed.
The working principle of electric energy meter
(1) The induction electric energy meter is a meter in which the current of a fixed coil and the induced current in a conductive movable part (usually a disc) interact to produce a rotating meter proportional to the measured electric energy.
(2) Electronic watt-hour meter is a meter whose output is proportional to the measured electrical energy by acting on solid-state (electronic) components by current and voltage.
Energy meter classification
(1) According to structure and working principle
A. Induction electric energy meter (mechanical electric energy meter)
The induction watt-hour meter uses the principle of electromagnetic induction to convert the voltage, current, and phase into magnetic moments to drive the aluminum disk to rotate. The shaft (worm) of the disk drives the gear to drive the drum of the counter to rotate. The process of rotation is It is a process of accumulation of time. Therefore, the advantages of inductive watt-hour meters are that they are intuitive, dynamic and continuous, and do not lose data when power is off.
B. Electronic energy meter
The electronic electric energy meter uses analog or digital circuits to obtain the product of the voltage and current vectors, and then realizes the electric energy measurement function through the analog or digital circuits. Due to the application of digital technology, time-sharing meter, prepaid meter, multi-user meter, and multi-function meter have appeared one after another, which further meets the demand for scientific and rational use of electricity.
C. Electronic electronic meters can be further divided into full electronic energy meters and electromechanical pulse energy meters.
(2) According to the accuracy level
A. Normal level: 0.25, 0.2, 0.55, 1, 2, and 3 levels, used to measure electrical energy.
B. Precision level: 0.01, 0.05 level, mainly used as the calibration benchmark for calibrating ordinary-level electric energy meters.
(3) According to the nature of the power supply
AC and DC energy meters.
(4) According to purpose
A. Active energy meter: used to measure active electricity;
B. Reactive power meter: used to measure the reactive power of electricity generation, supply and consumption;
C. Maximum demand meter: it is a meter that calculates the amount of power consumed by a user and also instructs the user to average the maximum power in a specified time interval in the previous electricity billing cycle;
D. Tariff electric energy meter: The paid rate electric energy meter measures the electricity consumption and total electricity consumption of each period according to the requirements in a specified time period.
E. Multifunctional electric energy meter: In addition to measuring active and reactive energy, it also has two or more functions such as time sharing and demand measurement, and can display, store and output data.
(5) According to the wiring method
Direct access type, transformer access type
According to the different measuring circuits, it can be divided into single-phase electric energy meter, three-phase three-wire electric energy meter, and three-phase four-wire electric energy meter.
(6) Service life
Ordinary and long-life electric energy meters
(7) Communication method
485 electric energy meter, carrier electric energy meter, wireless energy meter, etc.
(8) Rate method
Single rate electric energy meter, multi-rate electric energy meter