Basic concepts of electric energy measurement
Electric energy is different from other products. First of all, it is invisible and untouchable. In the process of use, it can not be directly determined by human sensory organs. It must be measured by special equipment. This kind of electric energy metering device is specially used for measuring electric energy. In addition, electric energy can not be stored, so in the process of electric energy production, transmission and use, the power sector needs to install a large number of electric energy metering devices to correctly and timely understand the amount of electric energy in each link.
Brief introduction of electric energy meter
The electric energy meter is used to measure the electric energy consumed in the circuit. It is also called watt hour meter, fire meter, electric energy meter and ten million hour meter.
Name plate marking of electric energy meter
Contents of signs
Name and model (the name and model shall be officially issued by the competent department);
The number of the standard (according to the national standard);
Trademark and manufacturer;
Product number;
Accuracy level (in circle or with "cl.xx");
Year of manufacture;
Unit of measurement (kW, kW · h, kvar, kvar · h);
Basic current (IB) and maximum current (IMAX);
Phase number, line number and reference voltage (V);
Reference frequency (Hz);
Constant of electric energy meter;
50. Identification or writing indicating the function concerned
In addition to the above problems, it is also necessary to inspect according to the customer, and pay attention to the problems such as wrong printing, stains, unclear printing, etc.
The principle of electric energy meter
The induction watt hour meter is a kind of instrument which can produce the rotation proportional to the measured electric energy by the interaction between the current of the fixed coil and the induced current in the conductive movable part (generally the disc).
Electronic watt hour meter is an instrument that produces an output proportional to the measured electrical energy by applying current and voltage to solid (Electronic) components.
Classification of electric energy meters
According to structure and working principle
Mechanical energy meter
The induction watt hour meter uses the principle of electromagnetic induction to turn the voltage, current and phase into magnetic torque to drive the aluminum disc to rotate. The shaft (worm) of the disk drives the drum wheel of the gear driven metering device to rotate. The process of rotation is the process of time accumulation. The advantage of power loss and no power loss is that the power meter is dynamic.
Electronic watt hour meter
Electronic watt hour meter uses analog or digital circuit to get the product of voltage and current vector, and then through analog or digital circuit to achieve energy metering function. Due to the application of digital technology, time-sharing meter, prepayment meter, multi-user energy meter and multi-functional energy meter are on the scene one after another, which further meets the needs of scientific and reasonable power consumption.
Electronic electronic meters can be further divided into electronic watt hour meters and electromechanical pulse electric energy meters.
According to accuracy level
Ordinary level: 0.25, 0.2, 0.55, 1, 2, 3, used for measuring electric energy.
Precision level: 0.01, 0.05, mainly used as the calibration benchmark for ordinary level watt hour meter.
AC and DC energy meters according to the nature of the connected power supply.
By use
Active energy meter: used to measure the active power;
Reactive energy meter: it is used to measure the reactive energy of power generation, supply and consumption;
Maximum demand meter: it is a kind of electric energy meter that calculates the quantity of electricity consumption of users, and also indicates the average maximum power of users in the specified time interval in the last electricity billing cycle;
Rate electric energy meter: the charge rate meter is a meter for measuring the electricity consumption and total electricity consumption in each period according to the requirements in the specified time period.
Multi function electric energy meter: in addition to measuring active and reactive energy, it also has more than two functions such as time sharing and measuring demand, and can display, store and output data.
According to the connection mode, it can be divided into single-phase watt hour meter, three-phase three wire watt hour meter and three-phase four wire watt hour meter according to different measuring circuits.
Service life, ordinary and long life watt hour meters
Communication mode, 485 watt hour meter, carrier watt hour meter, radio energy meter, etc
Rate mode, single rate watt hour meter, multi rate watt hour meter