RU2161334C1 - Device to transmit and receive signals in three-phase electrical network - Google Patents

Abstract

FIELD: electrical engineering. SUBSTANCE: invention can find application in organization of communication channels with use of 0.38-10.0- 35.0-110.0 kV power lines without their processing with high-frequency rejection filters. Proposed device uses synchronous detection of signals with employment of integration whose start and finish are determined by characteristic points which are common moments of time of transition of common supply voltage through zero in one of phases of network in transmission and reception points. Technical objective of invention is rise of noise immunity and expansion of frequency range from 1 to 3 kHz. EFFECT: rise of noise immunity and expansion of frequency range. 1 dwg

Description

 The invention relates to the field of electrical engineering and can find application in organizing communication channels using lines / 0.38 - 10 - 35 - 110 / kV without processing them with high-frequency chokes. A new technical result is the expansion of the frequency range from 1000 to 3000 Hz at a signal transmission rate of 50 and 100 Baud, as well as increasing the noise immunity of signal reception.

 In the proposed device, synchronous signal detection using integration is used, the beginning and end of which are determined by characteristic points, which are common points of the transition time through zero of the total supply voltage U (t) at the points of transmission and reception. At the same time, the quartz frequency of the signal voltage is used as the heterodyne voltage.

 A device for transmitting and receiving signals in a three-phase electric network, which is implemented in the device by AS USSR 1819025, class C 08 C 19/12, 1988. A disadvantage of the known device is the low noise immunity when receiving signals and low, no more than 10 Baud, signal transmission speed.

 Closest to the claimed device is a device for transmitting and receiving signals in a three-phase electric network, which is implemented in patent for invention N 2121759, class. 6 H 04 B 3/54, BI N 31, 11/10/98, adopted as a prototype.

на

в заявленном устройстве позволит улучшить отношение сигнал/помеха. Так, в прототипе при скорости передачи сигналов 100 Бод, где

и при максимальной частоте запуска передатчика f₀≈f₂=1000 Гц неравенство будет иметь вид:

или 0,01 >> 0,001, т.е. левая часть неравенства будет больше в 10 раз. Это значит, что за период интегрирования Т уложится 10 периодов напряжения частоты сигнала /помехи/.In the known device, the local oscillator voltage is formed from the harmonics of the frequency of the supply voltage F. Due to the fact that the frequency F ≠ 50 Hz in emergency conditions, the harmonics of the frequency F change their position on the frequency axis and filter out the local oscillator frequency in a fixed frequency band at high harmonic indices frequency f is complicated. Therefore, as practice has shown, it is necessary to be limited from above to the 20th harmonic (1000 Hz), which narrows the frequency range. The claimed device solves the problem of increasing the frequency range up to 3 kHz, since the frequency of the local oscillator uses the quartz frequency of the signal. Strengthening inequality in the prototype with

on the

in the claimed device will improve the signal-to-noise ratio. So, in the prototype at a signal transmission rate of 100 Baud, where

and at the maximum transmitter start frequency f ₀ ≈f ₂ = 1000 Hz, the inequality will be:

or 0.01 >> 0.001, i.e. the left side of the inequality will be 10 times more. This means that during the integration period T, 10 periods of voltage of the signal frequency / interference / will be stacked.

С учетом того, что f_Σ= f₁+f₂= 2f₀, неравенство примет вид:

или

т.е. левая часть неравенства будет больше в 160 раз. Это значит, что за период интегрирования Т уложится 160 периодов напряжения частоты сигнала /помехи/. Известно, что математическое ожидание М амплитуды помехи U_п(t), которая флуктуирует около нуля, описывают выражением: M[U_п(t)]--->0 при знаменателе в правой части неравенства _→ ∞. Таким образом, чем лучше выполняют неравенство, тем выше будет отношение сигнал/помеха после обработки сигнала в интеграторе. При увеличении частотного диапазона до 3 кГц неравенство еще "усилят" в три раза.In the claimed device, for example, with n = 3 and f ₀ = 1000 Hz, the inequality will be:

Given that f _Σ = f ₁ + f ₂ = 2f ₀ , the inequality takes the form:

or

those. the left side of the inequality will be 160 times more. This means that during the integration period T, 160 periods of voltage frequency of the signal / interference / will be laid out. It is known that the mathematical expectation M of the interference amplitude U _p (t), which fluctuates around zero, is described by the expression: M [U _p (t)] ---> 0 with the denominator on the right-hand side of the inequality _ → ∞. Thus, the better the inequality is fulfilled, the higher the signal-to-noise ratio after processing the signal in the integrator. With an increase in the frequency range up to 3 kHz, the inequality is still “amplified” three times.

обратной последовательности на частоте f₁ и ток сигнала

прямой последовательности на частоте f₂, где f₂-f₁= 2F, передают эти токи по трехфазной электрической сети в пункт приема, преобразуют

в напряжения

, преобразуют эти напряжения путем фильтрации соответственно в напряжения

и

где ω₁= 2πf₁; ω₂= 2πf₂ в узкой полосе пропускания частот, перемножают U₁(t) и U₂(t) выделяют путем фильтрации напряжение суммарной частоты

где ω_Σ= 2πf_Σ, f_Σ= f₁+f₂= 2f₀, f₀ - частота запуска передатчика, преобразуют напряжение U_Σ(t) в напряжение

путем n-кратного умножения и n-кратной фильтрации, где n= 1, 2, 3, 4, ..., умножают U_Σn(t) на U_Σn(t), из полученного напряжения выделяют путем фильтрации постоянную составляющую U_c, интегрируют U_c в интервале Т, где

при скорости передачи сигналов 50 Бод и

при скорости передачи сигналов 100 Бод, выполняют неравенство

при этом начало и конец интервалов передачи сигналов и интегрирования соответствуют единым моментам времени перехода общего питающего напряжения U(t) через ноль в пунктах передачи и приема.In the claimed device for transmitting and receiving signals in a three-phase electric network at a transmission point, the supply voltage U (t) of industrial frequency F is converted into a signal current

reverse sequence at frequency f ₁ and signal current

direct sequence at a frequency f ₂ , where f ₂ -f ₁ = 2F, transmit these currents through a three-phase electric network to the receiving point, convert

in tension

convert these voltages by filtration, respectively, into voltages

and

where ω ₁ = 2πf ₁ ; ω ₂ = 2πf ₂ in a narrow passband of frequencies, multiply U ₁ (t) and U ₂ (t) isolate by filtering the voltage of the total frequency

where ω _Σ = 2πf _Σ , f _Σ = f ₁ + f ₂ = 2f ₀ , f ₀ is the transmitter startup frequency, the voltage U _Σ (t) is converted to voltage

by n-fold multiplication and n-fold filtering, where n = 1, 2, 3, 4, ..., multiply U _Σn (t) by U _Σn (t), from the obtained voltage the DC component U _c is isolated by filtration, integrate U _c in the interval T, where

at a signal rate of 50 baud and

at a signal transmission rate of 100 Baud, the inequality

at the same time, the beginning and the end of the signal transmission and integration intervals correspond to the unified moments of the transition time of the total supply voltage U (t) through zero at the points of transmission and reception.

Device / cm. the drawing / that implements the claimed method, contains in the transfer point synchronizer 1 characteristic points / synchronizer /, transmitter 2 passive-active type / transmitter /, three-phase electrical network 3 / network /, voltage filter of symmetrical components / FSS / reverse sequence 4, FSS direct sequence 5, narrow-band filter 6 / UPF / frequency f ₁ , UPF 7 frequency f ₂ , multiplier 8, UPF 9 frequency f _Σ = f ₁ + f ₂ , first 10, second 11, ...... n-th 12 frequency converter / converter /, multiplier 13, low-pass filter / low-pass filter / 14, integrator 15, synchronous Isator 16, phase shifter 17.

 A device for transmitting and receiving signals in a three-phase electrical network / network /, in which at the points of transmission and reception one of the phases of the network 3 is connected respectively to the inputs of the first 1 and second 16 characteristic point synchronizers / synchronizer /, the output of the first synchronizer 1 is passively connected to the transmitter input -active type 2, the output of which is connected to the three phases of the network 3, at the reception point, the inputs of the voltage filters of the symmetrical components / FSS / negative sequence 4 and the FSS direct sequence are connected respectively to the three phases of the network 3 5, the outputs of each of which are connected respectively to the inputs of the first 6 and second 7 narrow-band filters / UPF /, the outputs of each of which are respectively connected to the first and second inputs of the first multiplier 8, the output of the second synchronizer 16 is connected to the input of the phase shifter 17, the output of which is connected to the second input of the integrator 15, while the output of the first multiplier 8 is connected to the input of the third UPF 9, the output of which is connected to the input of the first converter 10, the output of which is connected to the input of the second converter 11 ........, Exit is connected to the n-th input of the inverter 12, whose output is connected to the combined second inputs of the multiplier 13, whose output is connected to the input of the LPF 14, whose output is connected to the first input of the integrator 15.

 The device operates as follows.

мгновенные значения которых описывают выражениями:

где I_m - амплитудное значение токов на частотах ω₁ и ω₂, ω₁= (ω₀-Ω) и ω₂= (ω₀+Ω); ω₀= 2πf₀; Ω = 2πF; f₁=f₀-F; f₂=f₀+F;

f₀ - частота запуска передатчика.The synchronizer 1 generates pulses at the transmission point at single moments of the transition time of the supply voltage U (t) of the frequency F through zero. The beginning and end of signal transmission coincide with the unified moments of the transition time of the supply voltage U (t) of frequency F through zero at the points of transmission and reception. When the transmitter 2 in its phase wires A, B, C form the following signal currents by analogy with the prototype

the instantaneous values of which are described by the expressions:

where I _m is the amplitude value of currents at frequencies ω ₁ and ω ₂ , ω ₁ = (ω ₀ -Ω) and ω ₂ = (ω ₀ + Ω); ω ₀ = 2πf ₀ ; Ω = 2πF; f ₁ = f ₀ -F; f ₂ = f ₀ + F;

f ₀ - transmitter start frequency.

мгновенные значения которых описывают выражениями:

где U_A, U_B, U_C - фазные напряжения сигнала,
Из выражения /2/ следует, что на частоте ω₁ имеют напряжения обратного чередования фаз A, C, B, на частоте ω₂ - прямого чередования фаз, A, B, C. Напряжение сигнала обратной последовательности на частоте ω₁ принимает ФСС 4. Напряжение сигнала прямой последовательности на частоте ω₂ принимает ФСС 5. Выражение мгновенных значений напряжений сигнала на соответствующих выходах ФСС 4 и ФСС 5 имеют вид:

В связи с тем, что в качестве напряжения гетеродина используют напряжение сигнала кварцованной частоты, фазовые сдвиги опускаем. Эти напряжения получены в широкой полосе ФСС 4 и ФСС 5, их соответственно подают на УПФ 6 и УПФ 7. На выходе УПФ 6 имеют напряжение U₁(t), на выходе УПФ 7 - U₂(t).These currents form at the inputs of the FSS 4 and FSS 5 three-phase voltage of the reverse and forward sequences

the instantaneous values of which are described by the expressions:

where U _A , U _B , U _C - phase voltage of the signal,
From the expression / 2 / it follows that at a frequency ω ₁ they have reverse phase voltages A, C, B, at a frequency ω ₂ - direct phase rotation, A, B, C. The voltage of the negative sequence signal at a frequency ω ₁ takes FSS 4. The voltage of the direct sequence signal at a frequency of ω ₂ takes the FSS 5. The expression of the instantaneous values of the signal voltages at the corresponding outputs of the FSS 4 and FSS 5 are:

Due to the fact that the voltage of the quartz frequency signal is used as the local oscillator voltage, we omit the phase shifts. These voltages were obtained in a wide band of FSS 4 and FSS 5; they are respectively supplied to UPF 6 and UPF 7. At the output of UPF 6 they have voltage U ₁ (t), and at the output of UPF 7 they have U ₂ (t).

В умножителе 8 перемножают U₁(t) и U₂(t), в результате получают напряжения разностной и суммарной частот

В прототипе выделяют разностную частоту, в заявленном устройстве выделяют суммарную частоту с помощью УПФ 9.

In the multiplier 8, U ₁ (t) and U ₂ (t) are multiplied, as a result, the voltages of the difference and total frequencies

In the prototype, the difference frequency is isolated, in the inventive device, the total frequency is isolated using UPF 9.

где ω_Σ= 2πf_Σ, f_Σ= f₁+f₂= 2f₀.
Напряжение U_Σ(t) подают на вход первого преобразователя 10. Преобразователь состоит из умножителя 10¹ , который своими объединенными входами подключен к выходу УПФ 9, а выход умножителя 10¹ подключен к входу УПФ 10², выход которого является выходом преобразователя 10, который подключен к входу второго преобразователя 11. Так как работа преобразователей идентична, рассмотрим работу первого, второго и n-го преобразователей.

where ω _Σ = 2πf _Σ , f _Σ = f ₁ + f ₂ = 2f ₀ .
The voltage U _Σ (t) is supplied to the input of the first converter 10. The converter consists of a multiplier 10 ¹ , which is connected to the output of the UPF 9 by its combined inputs, and the output of the multiplier 10 ^{1 is} connected to the input of the UPF 10 ² , the output of which is the output of the converter 10, which connected to the input of the second Converter 11. Since the operation of the converters is identical, consider the operation of the first, second and nth converters.

Выделяют с помощью узкополосного фильтра 10² напряжение суммарной частоты, которое будет выходным для преобразователя 10 и входным для второго преобразователя 11.At the output of the multiplier 10 ¹ by analogy with / 7 /, they have the voltage of the differential and total frequencies:

Using the narrow-band filter 10 ^{2, the} voltage of the total frequency is extracted, which will be output for the converter 10 and input for the second converter 11.

По аналогии с /10/ напряжение на выходе второго преобразователя 11 будет равно:

Напряжение на выходе n-го преобразователя будет равно:

Таким образом каждый последующий преобразователь дает напряжение с двойной частотой. Путем n-кратного умножения и n-кратной фильтрации получают нужное значение частоты 2ⁿ•ω_Σ. Напряжение U_Σn(t) с выхода n-го преобразователя 12 подают на умножитель 13, имеющий объединенные входы. С выхода умножителя 13 имеют напряжения с разностной и суммарной частотами:

С помощью ФНЧ 14 выделяют напряжения разностной частоты, т.е. напряжение постоянной составляющей U_c.

By analogy with / 10 / the voltage at the output of the second Converter 11 will be equal to:

The voltage at the output of the nth converter will be equal to:

Thus, each subsequent converter gives a voltage with a double frequency. By n-fold multiplication and n-fold filtering, we obtain the desired frequency value 2 ⁿ • ω _Σ . The voltage U _Σn (t) from the output of the nth converter 12 is supplied to a multiplier 13 having combined inputs. From the output of the multiplier 13 have voltages with difference and total frequencies:

Using the low-pass filter 14, the difference frequency voltages are isolated, i.e. DC voltage U _c .

U_c будет являться амплитудой /огибающей/ сигнала. U_c подают на первый вход интегратора 15, на второй вход которого подают импульсы синхронизатора 16 через фазовращатель 17, с помощью которого совмещают единые моменты времени начала и конца интервала интегрирования Т с началом и концом передачи сигнала. Выход интегратора 15 является информационным.

U _c will be the amplitude / envelope / signal. U _{c is} fed to the first input of the integrator 15, to the second input of which pulses of the synchronizer 16 are fed through the phase shifter 17, with the help of which the single moments of the start and end of the integration interval T are combined with the beginning and end of the signal transmission. The output of the integrator 15 is informational.

Thus, we have proved that in the claimed device have:
1. The operating frequency range in the tonal range is increased from 1 to 3 kHz and the choice of the transmitter start frequency f ₀ does not depend on the instability of the frequency F of the supply voltage U (t).

где n выбирают в зависимости от технических требований получения заданного отношения сигнал/помеха на информационном выходе интегратора 15.02. The noise immunity in the claimed device is increased due to the implementation of more "hard" inequality

where n is selected depending on the technical requirements for obtaining a given signal / noise ratio at the information output of the integrator 15.0

Claims (1)

A device for transmitting and receiving signals in a three-phase electric network, in which at the point of transmission one of the phases of the network is connected to the inputs of the first synchronizer, the output of which is connected to the input of a passive-active type transmitter whose output is connected to the three phases of the network, at the reception point the input of the second synchronizer connected to one of the phases of the network, the inputs of the voltage filter, converted from the current of the signal of the negative sequence, and the filter of voltage, converted from the signal current, are directly connected to the three phases of the network the first sequence, the outputs of each of which are connected respectively to the inputs of the first and second narrow-band filters, the outputs of each of which are respectively connected to the first and second inputs of the first multiplier, the output of the second synchronizer is connected to the input of the phase shifter, the output of which is connected to the second input of the integrator, the third narrow-band filter , the second multiplier, a low-pass filter, characterized in that n frequency converters are introduced into it, the output of the first multiplier is connected to the input of the third narrow-band about the filter, the output of which is connected to the input of the first frequency converter, the output of the nth frequency converter is connected to the combined inputs of the second multiplier, the output of which is connected to the input of the low-pass filter, the output of which is connected to the first input of the integrator, and each subsequent frequency converter is connected to the previous one a frequency converter, and the frequency converters are capable of multiplication and filtering U _Σ (t) of the sum frequency to obtain the voltage value of the frequency 2 ⁿ ω _Σ, where _{ω Σ = 2πf Σ, f Σ} = f ₁ + f _2, f ₁ f ₂ - frequency current feedback signals, respectively, and direct-sequence converted from commercial frequency supply voltage.