CN2415366Y

CN2415366Y - Electronic type three-phase KWH meter

Info

Publication number: CN2415366Y
Application number: CN 00229549
Authority: CN
Inventors: 邱求元; 王育梅; 张军
Original assignee: SIDA ELECTRONIC INSTRUMENTS CO Ltd HENAN PROV
Current assignee: SIDA ELECTRONIC INSTRUMENTS CO Ltd HENAN PROV
Priority date: 2000-03-29
Filing date: 2000-03-29
Publication date: 2001-01-17
Anticipated expiration: 2010-03-29

Abstract

The utility model relates to an electronic type three-phase KWH meter, the output end of a current sampler is connected with the input end of a current sampled signal of a measuring chip, the metering pulse output end of the metering chip is connected with a counter, a three-phase incoming line of a KWH meter forms a star connection via a network resistor with a same resistance value, an electric current sampler is connected among one of phases of inlet and outlet lines, other two phases inlet and outlet lines are short-circuited, and the speed ratio of the counter is one third of a single-phase KWH meter. The utility model effectively solve the problem that a neutral of a farm machinery can not be led out, the cost of the utility model can be sharply lowered, and the utility model is widely suitable for three phase equilibrium load user.

Description

A kind of electronic type three phase watt-hour meter

The utility model relates to a kind of three phase watt-hour meter, especially relates to a kind of electronic type three phase watt-hour meter.

The at present domestic three-phase electronic watt-hour meter that is used to measure the three-phase active energy mainly contains following two kinds: a kind ofly promptly directly carry out A, B, C three-phase active energy accumulation calculating in table, this is at present the most general: another kind is the three phase watt-hour meter that adopts the two elements method, and it mainly is to stride adding up of phase active energy by two to realize what the three-phase active energy calculated.Based on the three-phase electronic watt-hour meter that these two kinds of methods are manufactured, because technology is taken into account a lot of and its process complexity of face, so price is also than higher.Its price still is unacceptable for the vast rural subscribers of China.Though tradition induction type three phase watt-hour meter price is not high, with respect to electron watt-hour meter, there are many inferior positions that are unfavorable for the standard management of power use in it.Exist accuracy of measurement to be subjected to problems such as the installation site influences, anti-electricity-theft poor performance as the induction type table.Make electron watt-hour meter that low price meets simultaneously metrological legislation again becomes numerous rural subscribers' active demand for this reason.The well irrigations that adopt are cultivated in present farmland more by China, in addition, the motor of the electrorammer that use flow-type motor such as building ground, interim processing stand etc., its propulsion system mostly are the three-phase squirrel cage motor, be three-phase balancing load,, can only adopt the phase three-wire three table the metering of this electrical equipment because request for utilization inconvenience inserts center line, but have the cost height, mounting means is to the big problem of precision influence.So some places generally adopt timer to measure electric energy.Still there is low, the shortcoming intuitively not of accuracy, is difficult for being accepted by the peasant.Along with further implementing of the upgrading of rural power grids, press for a kind of simple and easy three-phase table power consumption, that the installation site do not had specific (special) requirements that cheaply, directly shows.

The purpose of this utility model is to provide a kind of and adopts artificial neutral point mode to measure the electronic electric meter of three-phase three-wire system balanced load active energy.

For achieving the above object, the utility model adopts following technical scheme: a kind of electronic type three phase watt-hour meter, comprise watchcase, be contained in metering circuit and register in the watchcase, metering circuit comprises current sampler, voltage sample branch road and computation chip, the current sampler output terminal connects computation chip current sampling signal input end by the High frequency filter element, the metrical pulse output termination register of computation chip, the three-phase inlet wire of watt-hour meter is Y-connection by three groups of identical network resistors of resistance value respectively, current sampler is connected on wherein and one passes in and out between the line mutually, other two-phase turnover line short circuit, voltage sample network resistor branch road be connected to current sampler one network resistor parallel connection mutually, the speed ratio of register is 1/3rd of a single-phase watt-hour meter.

Wherein the line voltage of two-phase connects computation chip operating voltage input end by dividing potential drop, rectification, filtering, mu balanced circuit.

Used current sampler is the copper-manganese sheet.

The output terminal of computation chip connects watt-hour meter verification terminal by optocoupler.

The utility model adopts artificial neutral point mode, and by changing the speed ratio of register, making only needs the electric energy of arbitrary phase in the measurement three-phase three-wire system symmetric circuit can draw the active energy of three-phase, not only solved the problem that the agricultural machinery neutral point can't be drawn effectively, and simplified the metering circuit of electronic type three phase watt-hour meter greatly, its cost is reduced significantly, be convenient to vast rural area three-phase balancing load user and accept.

Further specify the utility model below in conjunction with accompanying drawing and by embodiment:

Fig. 1 is the one-piece construction synoptic diagram of embodiment;

Fig. 2 is the circuit theory synoptic diagram of embodiment.

Embodiment: metering circuit wiring board 5 is housed in the watchcase 2, the three-phase turnover line of watt-hour meter carries out wiring by terminal base 1, copper-manganese sheet 3 (being equivalent to the R0 among Fig. 2) is installed by screw 4, register 6 (being equivalent to the M among Fig. 2) is equipped with because the physical construction of electron watt-hour meter is prior art in the top in the watt-hour meter, is not described in detail in this.

Current sampler copper-manganese sheet R0 is connected on A and passes in and out mutually between the line in the present embodiment, and B phase, C pass in and out the line short circuit mutually.A, B, C phase inlet wire are by three group network resistance Y-connections, and A phase, B group, C group network resistance are respectively R ₀₀₁, R ₀₀₂, R ₀₀₃, three-phase network resistance is high-power resistance, makes three group network resistive impedance values equate that then the N of stellate node place is artificial neutral point by debugging.Copper-manganese sheet R ₀In the current sampling signal output terminal by high-frequency filter circuit R ₁, R ₂, C ₁, C ₂Connect current sampling

signal input pin

1,2 pin of special-purpose computation chip BL0932.Voltage sample network resistor branch road R ₃, R ₄'～R ₁₇With R ₀₀₁The network resistor parallel connection, the voltage signal sampling end is taken from resistance R ₁₈With R ₂₀Between and be connected to 4 pin of computation chip BL0932.The operating voltage of computation chip BL0932 adopts the alternate line power voltage supply of A, C, via D ₁, D ₂Rectification, C ₉, C ₁₀Filtering, D ₃, D ₄After the voltage stabilizing formation+5V and-17,11,10 pin that 5V voltage is connected to BL0932 provide required voltage for its work.R among the figure ₆, R ₆', R ₆" be voltage dependent resistor (VDR), be used for overcurrent protection between line.

The electric energy measurement principle of embodiment is: the required current signal of special chip BL0932 is taken from copper-manganese sheet R ₀, via R ₁, R ₂, C ₁, C ₂High frequency filter, sampled signal are delivered to

chip

1,2 pin, and voltage signal is taken from the network resistor (R between artificial neutral point N and the A phase ₃, R ₄'～R ₁₇), signal is delivered to chip 4 pin, and two sampled signals convert through chip internal, and with the marker pulse constant, other is through optocoupler IC in the 8th output high frequency power pulse ₂Export terminal to and can supply verify error.13,14 pin output pulsed drive register M carries out the indication of power consumption.Because this table is used to measure the electric energy of three-phase balancing load, abide by a table ratio juris, multiply by 3 after the metering by a phase electric energy and measure three-phase electric energy.3 the work of multiply by in the table is that the change by the register speed ratio realizes.Even the register speed ratio is the former single-phase First Astronautic Research Institute for Measurement and Test use 1/3, can make the electricity consumption of register indication three-phase.

Claims

1, a kind of electronic type three phase watt-hour meter, comprise watchcase, be contained in metering circuit and register in the watchcase, metering circuit comprises current sampler, voltage sample branch road and computation chip, the current sampler output terminal connects computation chip current sampling signal input end by the High frequency filter element, the metrical pulse output termination register of computation chip, it is characterized in that: the three-phase inlet wire of watt-hour meter is Y-connection by three groups of identical network resistors of resistance value respectively, current sampler is connected on wherein and one passes in and out between the line mutually, other two-phase turnover line short circuit, voltage sample network resistor branch road be connected to current sampler one network resistor parallel connection mutually, the speed ratio of register is 1/3rd of a single-phase watt-hour meter.

2, three phase watt-hour meter as claimed in claim 1 is characterized in that: wherein the line voltage of two-phase connects computation chip operating voltage input end by dividing potential drop, rectification, filtering, mu balanced circuit.

3, three phase watt-hour meter as claimed in claim 1 or 2 is characterized in that: used current sampler is the copper-manganese sheet.

4, three phase watt-hour meter as claimed in claim 1 or 2 is characterized in that: the output terminal of computation chip connects watt-hour meter verification terminal by optocoupler.