CN2083756U - High-recision multi-function intelligent kilowatt-hour meter - Google Patents

Abstract

The utility model discloses a complete electronic kilowatt-hour meter, which is composed of a voltage and current transformer (1), a transmitter (2), an A/D converter (3), a single-chip computer (4), a data memory (5), a program memory (6), a clock system (7), interface circuits (8) (9) (10) (11), a keyboard (12), an LEO digital display (13), a printer (14) and a communication port (15). The utility model can realize the measurements of the voltage, current, frequency, phase, power and electrical energy of a three-phase electric network, and the limitation of load and electric power consumption. The networking communication with the computer of an electric network can also be realized. Compared with the existing magnetoelectric induction kilowatt-hour meters, the utility model has the characteristics of high precision, multiple functions, intellectualization and excellent cost performance.

Description

High-recision multi-function intelligent kilowatt-hour meter

The utility model relates to the physical apparatus of measuring electric variable, further is meant a kind of high-accuracy multifunctional intelligent kilowatt-hour meter that adopts the full-electronic method to measure the time integral of electric power.

Existing watt-hour meter is generally magnetoelectric induction, and its measuring principle is outmoded, and function singleness, precision are not high, and energy consumption is higher because mechanical wear is big and the non-linear loss of electromagnetism is big, and will expend a large amount of copper, aluminium non-ferrous metal during manufacturing.If its measuring accuracy will be improved a grade, need take many measures, but cost increases greatly, be 1 class precision so be installed in the installing type three phase watt-hour meter of power house, transformer station at present.

The purpose of this utility model provides a kind of watt-hour meter of full electronic, makes its precision height, function many, and realizes intelligent.

The solution of this Watt-hour meter is to realize like this, referring to Fig. 1 the utility model electricity functional-block diagram, its circuit part is by voltage and current transformer (1), transmitter (2), A/D converter (3), one-chip computer (4), data memory (5), memory under program (6), clock system (7), interface circuit (8), to (11), keyboard (12), LED digital indicator (13), printer (14) and communication port (15) are formed, the annexation of circuit and signal flow are to being: voltage and current transformer (1) are with the voltage in the electrical network, electric current, cycle, after signals such as phase place are given transmitter (2) and are carried out conversion, carry the level signal that is suitable for its compatibility for A/D converter (3) by transmitter (2), carry out computing through A/D converter (3), calculate every measuring-signal of gained, remove and be stored in data memory (5) at home and abroad by bus, also send LED digital indicator (13) to show and printer (14) printout through interface circuit (9) and (11) respectively by bus, the outside memory under program (6) that connects the storage working procedure by bus of one-chip computer (4), clock system (7) links to each other with one-chip computer (4) by bus, keyboard (12) carries out manual presetting by interface circuit (8) to one-chip computer (4), except that LED digital indicator (13) and printer (14) are controlled, also provide the brownout amount by interface circuit (10) to this device outside by one-chip computer (4), the restriction load, peak Elapsed Time, the control signal that the valley power consumption time etc. presets, one-chip computer (4) also joins by its delivery outlet and communication port (15), so that with the external computer system communication, realize networking remote measurement and control.Owing to the utlity model has the foregoing circuit annexation, so the user can enter one-chip computer (4) through interface circuit (8) by keyboard (12), require to show measured signal value, also can preset various parameters, send into one-chip computer (4) for processing by keyboard (12).One-chip computer (4) by after the various parameters of the digital signal of A/D converter (3) input and keyboard (12) input are carried out computing and handling, is gone up at LED digital indicator (13) and to be shown, thereby can carry out following measurement under the cooperation of software:

Voltage measurement; Current measurement; The active electrical degree metering; The killovar-hour meter amount; Active electrical degree time-sharing measurement (during the peak, during paddy, at ordinary times); Idle electric degree time-sharing measurement (during the peak, during paddy, at ordinary times); Wattful power messurement; Wattless power measurement; Frequency measurement; Phase measurement.

The control signal that can preset from interface circuit (10) export-restriction power consumption (as early warning in 90% o'clock), restriction load (as time-delay in 5 minutes), peak Elapsed Time and valley power consumption time etc. also, connect usefulness for external circuit, with the control that realizes external electric system and make corresponding warning indication.

The utility model is compared with existing magnetoelectric induction watt-hour meter, has following advantage: 1. precision height.Owing to adopted brand-new measuring principle, the hardware unit all electronic does not have any mechanical hook-up, and calculates and manage with single chip microcomputer, makes measuring accuracy reach more than 0.5 grade.2. function is many.Nearly tens kinds of a-table-multi-purpose, function, unconventional watt-hour meter in one's power.3. intelligent.Because computing machine can calculate, stores, input and output data and information, so the utility model watt-hour meter can read and print various measurement data at any time in the erecting stage, also can carry out manual presetting and modification; But the electric degree time-sharing measurement, and user power utilization amount and power load limited; Also can with electrical network and computer networking communication, realize electrical network uniform dispatching supervisory computerization.4. ratio of performance to price excellence.This watt-hour meter does not need to expend a large amount of copper, aluminium non-ferrous metal, and owing to adopt VLSI (very large scale integrated circuit) chip, has not only reduced energy consumption, and reliable operation, and is cheap.

Below in conjunction with drawings and Examples the utility model is further specified.

Fig. 1 is the utility model electricity functional-block diagram;

Fig. 2 and Fig. 3 combine and are the schematic diagram of a kind of physical circuit of Fig. 1 block scheme.

Referring to Fig. 2, voltage and current transformer (1) are made up of two cover voltage transformer pt summation current transformer CT.Referring to Fig. 2 and Fig. 3, transmitter (2) comprises that two covers are by operational amplifier IC ₁, diode D ₁To D ₄, resistance R ₁To R ₅And capacitor C ₁With C ₂The voltage transmission circuit of forming is by operational amplifier IC ₂, diode D ₅To D ₈, resistance R ₆To R ₁₁And capacitor C ₃With C ₄The electric current transmission circuit of forming, by operational amplifier IC ₃With IC ₄, d type flip flop IC ₅With IC ₆, stabilivolt D ₉With D ₁₀, resistance R ₁₄To R ₂₁And capacitor C ₅With C ₆Phase place and the frequency transmission circuit formed, and also comprise two four path analoging switch IC ₇IC wherein ₁And IC ₂Should adopt the integrated transporting discharging of open-loop gain, as adopting LN308, IC up to 100db ₃And IC ₄Then can adopt LN339, resistance R ₃, R ₅, R ₆, R ₁₀, R ₁₂And R ₁₃All should choose high stability precision resistance (0.1%), can guarantee that so just transmitter (2) has the input impedance height, carrying load ability is strong and the characteristics of precision high (more than 0.2 grade).According to the principle of work of transmitter, the uA(u among Fig. 2 _C), IA(Ic), f _A(f _C), ψ A(ψ _C) the end output valve can be used as respectively and measure A(C) phase power source voltage value, current value, frequency values and phase value, they are delivered to IC ₇Input end, and corresponding the demonstration handled and done to machine as calculated.After obtaining these four fundamental measurement values, when carrying out wattful power messurement, only need to have calculated just by computing machine by the formula of P=UIcos ψ, three-phase power measurement can be by computing machine P=U by formula _ABI _ABCos ψ _A+ U _CBCos ψ c tries to achieve.Wattless power measurement is different with wattful power messurement, just cos ψ is become sin ψ and gets final product.Electric energy is a power to the integration of time, and computing machine only need add up the value of measured active power (or reactive power) to time integral, can obtain power consumption, i.e. the electric degree number.

Referring to Fig. 3, A/D converter (3) is by analog to digital conversion piece IC ₈, rejection gate IC _16-1With IC _16-2, resistance R ₂₂To R ₂₅, potentiometer W ₁And capacitor C ₇To C ₁₂Form, IC8 can adopt ICL7109, and 12 double oblique integral formulas are adopted in this A/D conversion.One-chip computer (4) is by single-chip microcomputer IC ₂₂, 3-8 line code translator/divider IC ₁₉With eight D-latch IC ₂₀, crystal oscillator JA ₂, resistance R ₃₉And capacitor C ₁₆, C ₁₇With C ₂₀Form.IC ₂₂Adopt NCS8031, it has four parallel I/O interface, and its major function is: P ₀Mouthful, ternary bidirectional interface, data port, the least-significant byte address of storage double as exented memory with lock; P ₁Mouthful, P ₁₀, P ₁₁Be used as analog to digital conversion input selector control line, P ₁₂To P ₁₄Connect A/D conversion and high and low bit data respectively and keep P ₁₅, P ₁₆Be printer gating signal, P ₁₇Be IC ₂₃And IC ₁₇The selection signal; P ₂Mouthful, be used as exented memory most-significant byte address wire and chip selection signal; P ₃Mouthful, be used as and interrupt input and IC ₂₈With IC ₂₉Communication interface, input is through IC ₂₉, output through IC ₂₈Be connected with outer computer.Data memory (5) is IC ₁₇, can adopt the static RAM (SRAM) of 6264,8 8K bytes, the data of RAN are not lost when guaranteeing to have a power failure, and use by battery E, resistance R ₂₆, capacitor C ₁₃And diode D ₁₁The back-up source of forming is done power down protection.Memory under program (6) is IC ₁₈, can adopt 2764,8 8K byte EPROM.Clock system (7) is by real-time clock device IC ₂₁, crystal oscillator JA ₃, capacitor C ₁₄With C ₁₅, often open button AN and rejection gate IC _16-3With IC _16-4Form IC ₂₁Can adopt NSM 5832.Interface circuit (8) and (9) are by keyboard and display interface IC ₁₃, 4-16 line code translator/divider IC ₁₂, 6 buffering/driver ICs ₉To IC ₁₁, 6 buffering/driver ICs ₁₅, not gate IC ₁₄, K switch and resistance R ₂₇To R ₃₄Form.IC ₁₃Can adopt special purpose interface 8279, its key input section has shake removal function, and can latch the buffering key assignments; Show that output has the autoscan function, 16 LED digital indicators of multipotency load, IC ₉To IC ₁₂And IC ₁₅Be connected on IC ₁₃And between keyboard (12) and the LED digital indicator (13).IC ₁₂Can adopt 74LS154, IC ₁₅With IC ₉To IC ₁₁Can adopt 7407.Interface circuit (10) comprises parallel I/O expansion interface IC with (11) ₂₃, by 42 the input just with door IC ₂₆And resistance R ₃₈The interrupt control source of forming is by 14 binary string linage-counter/frequency divider IC ₂₇, crystal oscillator JA ₁And capacitor C ₁₈With C ₁₉The second interrupt source signal of forming is by operational amplifier IC ₂₄With IC ₂₅, stabilivolt D ₁₂And resistance R ₃₅To R ₃₇The power-fail interrupt testing circuit of forming.IC wherein ₂₃Can adopt 8155, it has two 8 bit parallel mouths of A, B, 16 C parallel port, and its function is: A mouth, 8 basic input/output states, wherein A ₀To A ₃For IC ₂₁With, A ₄Provide overload early-warning signal, A to the outside ₅Provide overload breaking output signal, A to the outside ₆Provided electric weight early warning signal, A to the outside ₇Provided electric weight breaking output signal to the outside; The B mouth, 8 basic input/output states are used for printer (14); The C mouth, 6 basic input states, C ₀With C ₁Be printer handshake usefulness, C ₂To C ₅For interrupt inquiry usefulness, wherein C ₂Be IC ₈Interrupt C ₃Be IC ₁₃Interrupt C ₄Be power-fail interrupt, C ₅For interrupting second.IC ₂₆Can adopt 7409, for outage, IC ₈, second interrupt and IC ₁₃Four interrupt sources use.The IC that interrupt second ₂₇Can adopt CD4060, it is own to 32.768KHZ crystal oscillator formation vibration and frequency division, and its output 256HZ signal is sent into IC ₂₃Timer internal, again the 256HZ frequency division is obtained a second interrupt source signal.The power-fail interrupt testing circuit adopts high input impedance amplifier TL082 as IC ₂₄And IC ₂₅, form two-stage series connection, to improve the output steepness.Communication port (15) is by four line drive IC ₂₈With four line receiver IC ₂₉Form IC ₂₈Can adopt 1488, IC ₂₉Can adopt 1489.

Claims (5)

1, a kind of high-accuracy multifunctional intelligent kilowatt-hour meter that adopts the full-electronic method to measure the time integral of electric power, it is characterized in that, circuit part is by voltage and current transformer (1), transmitter (2), A/D converter (3), one-chip computer (4), data memory (5), memory under program (6), clock system (7), interface circuit (8) is to (11), keyboard (12), LED digital indicator (13), printer (14) and communication port (15) are formed, after voltage and current transformer (1) are given the signal in the electrical network transmitter (2) and are carried out conversion, carry the level signal that is suitable for its compatibility for A/D converter (3) by transmitter (2), convert digital signal to through A/D converter (3) and carry out computing for one-chip computer (4), calculate every measuring-signal of gained, remove and be stored in data memory (5) at home and abroad by bus, also send LED digital indicator (13) to show and printer (14) printout through interface circuit (9) and (11) respectively by bus, one-chip computer (4) is outside to have connected memory under program (6) by bus, clock system (7) links to each other with one-chip computer (4) by bus, keyboard (12) carries out manual presetting by interface circuit (8) to one-chip computer (4), except that LED digital indicator (13) and printer (14) are controlled, also provide the brownout amount by interface circuit (10) to this device outside by one-chip computer (4), the restriction load, peak Elapsed Time, the control signal that the valley power consumption time etc. presets, one-chip computer (4) also joins by its delivery outlet and communication port (15).

2, watt-hour meter as claimed in claim 1 is characterized in that, voltage and current transformer (1) are made up of two cover voltage transformer pt summation current transformer CT, and transmitter (2) comprises that two covers are by operational amplifier IC ₁, diode D ₁To D ₄, resistance R ₁To R ₅And capacitor C ₁With C ₂The voltage transmission circuit of forming is by operational amplifier IC ₂, diode D ₅To D ₈, resistance R ₆To R ₁₁And capacitor C ₃With C ₄The electric current transmission circuit of forming, by operational amplifier IC ₃With IC ₄, d type flip flop IC ₅With IC ₆, stabilivolt D ₉With D ₁₀, resistance R ₁₄To R ₂₁And capacitor C ₅With C ₆Phase place and the frequency transmission circuit formed, and also comprise two four path analoging switch IC ₇

3, watt-hour meter as claimed in claim 1 is characterized in that, interface circuit (8) and (9) are by keyboard and display interface IC ₁₃, 4-16 line code translator/divider IC ₁₂, 6 buffering/driver ICs ₉To IC ₁₁, 6 buffering/driver ICs ₁₅, not gate IC ₁₄, K switch and resistance R ₂₇To R ₃₄Form.

4, watt-hour meter as claimed in claim 1 is characterized in that, interface circuit (10) comprises parallel I/D expansion interface IC with (11) ₂₃, by 42 the input just with door IC ₂₆And resistance R ₃₈The interrupt control source of forming is by 14 binary string linage-counter/frequency divider IC ₂₇, crystal oscillator JA ₁And capacitor C ₁₈With C ₁₉The second interrupt source signal of forming is by operational amplifier IC ₂₄With IC ₂₅, stabilivolt D ₁₂And resistance R ₃₅To R ₃₇The power-fail interrupt testing circuit of forming.

5, watt-hour meter as claimed in claim 1 is characterized in that, communication port (15) is by four line drive IC ₂₈With four line receiver IC ₂₉Form.

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