Classification of commonly used electric energy meters
(1) The electric energy meter can be divided into DC electric energy meter and AC electric energy meter according to the circuit used. AC electric energy meters can be divided into single-phase electric energy meters, three-phase three-wire electric energy meters and three-phase four-wire electric energy meters according to their phase lines.
(2) Electric energy meters can be divided into electrical mechanical energy meters and electronic energy meters (also known as static energy meters, solid-state energy meters) according to their working principles. Electromechanical electric energy meters are used in AC circuits as common electric energy measuring instruments, and the most commonly used one is induction electric energy meters. Electronic watt-hour meters can be divided into fully electronic watt-hour meters and electromechanical watt-hour meters.
(3) The electric energy meter can be divided into integral electric energy meter and split electric energy meter according to its structure.
(4) Electric energy meters can be divided into active energy meters, reactive energy meters, maximum demand meters, standard energy meters, multi-rate time-sharing energy meters, prepaid energy meters, loss energy meters, and multi-function energy meters according to their uses. Wait.
(5) The electric energy meter can be divided into ordinary installation electric energy meter (0.2, 0.5, 1.0, 2.0, 3.0 grade) and portable precision electric energy meter (0.01, 0.02, 0.05, 0.1, 0.2 grade) according to its accuracy grade.
The model of the electric energy meter and the meaning of the symbol on the nameplate
1. Model and its meaning
The electric energy meter model is represented by an arrangement of letters and numbers, and the content includes category code + group code + design serial number + derivative number.
(1) Category code. D an electric energy meter.
(2) Group code.
1) Represents the phase line: D a single phase; T a three-phase four-wire active power; S a three-phase three-wire active power; X a three-phase reactive power.
2) Indicating usage: B-standard; D-multifunctional; M-pulse; S-all electronic; Z-maximum demand. Y-prepayment: F-multiple rate.
(3) Design serial number. It is represented by Arabic numerals.
(4) Derivation number. T is used for both hot and humid and dry; TH is used for humid tropical zone; TA is used for dry tropical zone; G is used for plateau; H is used for ship; F is used for chemical anticorrosion.
E.g:
DD stands for single-phase electric energy meter, such as DD862 type, DD701 type, DD95 type.
DS stands for three-phase three-wire active energy meter, such as DS8, DS310, DS864, etc.
DT stands for three-phase four-wire active energy meter, such as DT862 and DT864.
DX stands for reactive energy meters, such as DX8, DX9, DX310, DX862.
DZ stands for the maximum demand meter, such as DZl type.
DB stands for standard electric energy meter, such as DB2 type and DB3 type.
2. Nameplate
The nameplate should contain the following:
(1) Trademarks.
(2) Measurement permission mark (CMC).
(3) The name or symbol of the unit of measurement, such as: "kWh" or "kWh" for active energy meter; "kvarh" or "kvarh" for reactive energy meter.
In the window of the word wheel counter, the integer and decimal places are distinguished by different colors, with a decimal point in the middle; if there is no decimal point, each word wheel of the window has a multiplication factor, such as ×100, ×10, ×1, etc. For the integer and decimal places of the LCD screen, there is a decimal point in the middle.
(4) The name and model of the electric energy meter.
(5) Basic current and rated maximum current. The basic current (calibration current) is the current value that determines the relevant characteristics of the electric energy meter. It is the basic working current of the electric energy meter, expressed in Ib; the rated maximum current is the maximum current value that the meter can meet the accuracy specified by its manufacturing standard. Expressed in Imax. For example, 1.5 (6) A means that the basic current value of the electric energy meter is 1.5A, and the rated maximum current is 6A. If the rated maximum current is less than 150% of the basic current, only the basic current is indicated. For a three-phase electric energy meter, the number of phases should be multiplied in front, such as 3×5 (20) A.
(6) Reference voltage. The reference voltage is the voltage value that determines the relevant characteristics of the electric energy meter, and is the working voltage of the electric energy meter, denoted by Un. For a three-phase three-wire electric energy meter, the reference voltage is expressed by multiplying the number of phases by the line voltage, such as 3×100V; for a three-phase four-wire electric energy meter, it is expressed by multiplying the number of phases by the phase voltage/line voltage, such as 3×220/380V; For single-phase electric energy meters, it is expressed by phase voltage, such as 220V.
(7) Reference frequency. The reference frequency is the frequency value that determines the relevant characteristics of the electric energy meter, that is, the power frequency, with hertz (Hz) as the unit.
(8) Electric energy meter constant. The electric energy meter constant is the constant of the relationship between the electric energy recorded by the electric energy meter and the corresponding number of revolutions or pulses. The active electric energy meter is expressed in the form of r(imp)/kwh or kwh/r(imp), and the reactive electric energy meter is expressed in the form of r( imp)/kvarh or kvarh/r (imp). The two constants have a reciprocal relationship with each other.
(9) Accuracy level. It is represented by the grade number entered in the circle, such as noodles. uniform,@. If there is no mark, the electric energy meter is regarded as level 2
(10) Symbols for the number of phases and lines.
(11) The ability to withstand environmental conditions is divided into 4 groups: P, S, A, and B.
(12) Manufacturing standards.