SU1408382A1 - Active and reactive power meter - Google Patents

Abstract

The invention relates to the field of electric power. The purpose of the invention is to expand the functionality, increase the speed and accuracy of measurements of the generation and consumption of active and reactive power in a generator-converter-consumer system. The counter contains sensors I and 2 current and voltage, multiplier 3, analog-digital converter 4, calculate, 16. b. yuk 17 input-output unit and display 18. A two-digit comparator 5, a multiplexer 6, counters 7 and 8, adders 9 and 10, registers 1 and 12 are entered into the counter. Blocks 13 ... 15 are mates with the calculator 16. b. yuk 19 synchronization and uirav.peny, as well as the formation of new functions. 1CT communication. A counter besides calculating the active i; reactive power can also determine the exchange energy. 1 il. and

Description

The invention relates to the field of power engineering and can be used in assessing the supply of electricity in energy electrical circuits to increase the efficiency of the distribution and transmission of electricity from the generator ij to consumers.

A: The purpose of the invention is to expand the functional and functional capabilities, increase the speed and accuracy of measurements of the generation and consumption of active and reactive 1-DISTANCE in the generator-converter-1 system-consumer system.

The drawing shows a block diagram of the active and reactive power counter.

The counter consists of current sensor 1, voltage sensor 2, multiplier 3, analog-to-digital converter (ADC) 4, two-comparator 5, multiplexer 6, counters 7 and 8, adders 9 and 10, registers 11 and 12, blocks 13 -15 interface with computer, computer 16, input-output unit 17, display unit 18, synchronization and control lock 19.

I The outputs of the I and 2 sensors of current and voltage are connected to the inputs of multiplier 3, the input | ADC 4 is connected to the output of multiplier 3, the input of ADC 4 is connected to the output of multiplier 3, the blocks 17 and 18 I / O and display are connected to the transmitter 16, the input | of the two-threshold comparator 5 is connected to the output of multiplier 3, and the first and second | outputs are connected to the first inputs of counters 7 and 8 and the first and second inputs (multiplexer 6, respectively, the third input of which is connected to the output of the ADC 4, 1 OUTPUTS of the counters 7 and 8 are connected to the first and second inputs of interface 15 15 the transmitter 16, the outputs of the multiplexer 6 through the first and second adders 9 and 10 and the first and second registers 11 and 12 are respectively connected to the inputs of blocks 13 and 14 of the interface with the transmitter 16, and the outputs of the first and second registers 11 and 12 are connected respectively to the second inputs of the first and second adders 9 and 10, the outputs of mates 13-15 with the calculator are connected to the inputs of the calculator 16, the first: output of the synchronization and control unit 19 is connected to the control input of the multiplier 3, the second to the inputs of the ADC control 4, counters 7 and 8, registers

I1 and 12, adders 9 and 10, and the third to the control inputs of the 13-14 interfacing unit with the computer and the computer 16.

The counter works as follows. The first inputs of multiplier 3 receive signals from current sensor I U, (t): a, (ux (t) and voltage sensor 2 Uu (t) en UBx (t), where a, - and "" are the coefficients determined gauge design.

After multiplying at the output of the multiplier 3, the voltage Uy (t) is formed,

five

0

0

0

five

0

five

five

0

proportional to the instantaneous power Pvh (1) 1 in (1) UBx (t), U.y (t) ay a (1)

where is the coefficient given by multiplier 3.

The output signal from the multiplier 3 is fed to the ADC 4 and two-threshold comparator 5.

At the output of the A / D converter 4, a digital code is formed corresponding to the value of the instantaneous mosh, PBx (t). The two-threshold comparator 5 makes it possible to determine the points in time when the instantaneous power Pcx (1) is positive, negative and equal to zero. The trigger thresholds of comparator 5 are set depending on the quantization step of the instantaneous power signal. The digital code of instantaneous power Pcx (1) and the signals from comparator 5 are sent to multiplexer 6, realizing the separation of the output signal from ADC 4 in accordance with the sign “-f- - instantaneous power P (t) 0,“ - - instantaneous power P (t); 0. The instantaneous power codes F (t) and P (t) are fed to adders 9 and 10, respectively, in which certain integrals of positive and negative power are calculated according to clock pulses (the adders have in fact a numerical integration of the instantaneous power functions P (t ) and P (t) with an integration step equal to the period of operation of the clock generator).

Information from adders 9 and 10 is entered into registers 11 and 12 when there is a signal from block 19. According to the signal, information from adders 9 and 10 is written into registers 11 and 12. The signal about the end of rewriting information from adders 9 and 10 to registers 11 and 12 is fed to the inputs of adders 9 and 10. After this, the contents of registers 11 and 12 are fed through blocks 13 and 14 into the calculator 16.

With counters 7 and 8, the time intervals f and t are determined when the instantaneous power is positive or negative. Counters 7 and 8 allow the presentation of the time intervals t and t in digital form.

In accordance with the signal from block 19, the signals from counters 7 and 8 through block 15 enter the calculator 16.

The calculator 16 calculates the active power by the formula p p- - + ri reactive power by the formula Q, | - (p- (r-ft °) p-t-);

where P J.ip (t) dt;

 P

(t) dt.

1 o

 (r-rr-a + P),

It also determines the exchange energy Wo6 | and Wo62 in accordance with the terms

Woi, R (G + 1 °)

Wo, (t ° + t-).

Claims (1)

Invention Formula An active and reactive power counter containing voltage and current sensors, a multiplier whose inputs are connected to the inputs of voltage and current sensors, an analog-to-digital converter whose input is connected to the multiplier output, a calculator and connected to it an I / O unit and a display unit characterized in that, in order to expand the functional capabilities, increase the speed and accuracy of measurements of generation and consumption of active and reactive power in the generator-converter-consumer system, introduced two-threshold comparator, two counters, multi0 0 5 A plexor, two adders, two registers, three interface blocks with a calculator, a synchronization and control unit, the input of a two-threshold comparator is connected to the multiplier output, and the first and second outputs are connected to the first inputs of the counters and the first and second inputs of the multiplexer, respectively, the third the input of which is connected to the output of the analog-to-digital converter, the outputs of the meters are connected to the first and second inputs of the first interface block with the calculator, the multiplexer outputs are connected through serially connected first and the second adders and the first and second registers are respectively connected to the inputs of the second and third interface blocks with the calculator, and the outputs of the first and second registers are connected respectively to the second inputs of the first and second adders, the outputs of the converter block interfaces are connected to the calculator inputs, the first output the synchronization and control unit is connected to the control input of the multiplier, the second to the control inputs of the analog-digital converter, counters, registers, adders, and the third to the control inputs of the block interfacing with the calculator and the calculator.