RU2260248C2 - Device for signal current input in low-voltage communication line of $$$ - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: proposed device can be used in low-voltage lines of 220 V to organize communication channel at frequencies ranging between 13 and 23 kHz included in remote burglar alarm communication system for objects, such as suburban plots of land, garages, shops, and the like, where means for telephone and radio communication with home affairs agency are not available.

EFFECT: enhanced signal transfer speed.

1 cl, 2 dwg

Description

The invention relates to the field of electrical engineering and can be used in low-voltage lines 220 V for the formation of a communication channel at frequencies in the range (13-23) kHz, which is part of a security television alarm system of objects, which can be summer cottages, garages, retail outlets, etc. .d., where there is no telephone and radio communications with air traffic control.

A known passive-active type generator, which is designed to input signal currents into three phases of the 0.38 kV line. This generator operates in the frequency range (500-3000) Hz and is designed to transmit signal currents along the (0.38-10-35) kV lines. The frequency range is selected taking into account the line lengths (10-35) kV.

Currently, the maximum transmission rate of signal currents that can be implemented in this frequency range is 50 Bit / s, which is a drawback [Л1].

A passive-active type generator is also known, which introduces signal currents into two phases. This generator is taken as a prototype [L1]. The disadvantages of the prototype are the same as that of the analogue.

In the claimed device Tsagareishvili S.A. By inputting the signal currents to the 220 V low-voltage line according to the “Phase-Earth” scheme, it was possible to significantly increase the signal transmission speed, and the channel itself is formed only by low-voltage lines of 220 V. In the following, the device will be called a generator.

Figure 1 shows a diagram of a generator of currents of signals of a passive type (generator), which implements the claimed technical solution,

Where:

1. A half-wave rectifier bridge (bridge), which consists of diodes D ₁ , D ₂ , D ₃ , D ₄ .

2. The capacitor of a sequential oscillatory circuit (circuit).

3. Coil inductance.

4. Generator load resistor (first resistor).

5. Optional loop resistor (second resistor).

6. Managed key.

GENERATOR WORK

Consider the operation of the generator in the time interval when the potential of Phase 1 is higher than the potential of the "Earth" (the neutral point of the transformer is 10 / 0.4 kV, which is grounded).

FIRST STATE OF THE GENERATOR SCHEME

Between the first and second nodes of the bridge (Fig. 1), the circuit is not connected and no pulses are supplied to the information input of the key that control its operation, while between the third and fourth nodes of the bridge we will have a voltage U (t) _input , the effective value of which is 220 V

Where

- U (t) _in - input voltage between the third and fourth nodes of the bridge;

- амплитуда входного напряжения;-

- the amplitude of the input voltage;

- Ω = 2πF is the angular frequency;

- F = 50 Hz - voltage frequency U (t) _input .

Between the first and second nodes of the bridge we will have a half-wave rectified voltage U (t) _out , which after expansion in the Fourier series has the form [L ₂ ]:

Where

- амплитуда напряжения U(t)_вх;-

- the amplitude of the voltage U (t) _I ;

- Ω = 2πF is the angular frequency;

- F = 50 Hz - voltage frequency U (t) _input ;

- постоянная составляющая двухполупериодного выпрямленного напряжения U(t)_вх -

- the constant component of the half-wave rectified voltage U (t) _input

;-

;

- second harmonic voltage U (t) _out , where U _{m (100 Hz)} = 130 V - amplitude;

, где U_{m(200 Гц)}=26 В - амплитуда - напряжение четвертой гармоники;-

where U _{m (200 Hz)} = 26 V - amplitude - voltage of the fourth harmonic;

-

Where

U _{m (100 Hz)} = 130 V, U _{m (200 Hz)} = 26 V, U _{m (300 Hz)} = 11 V - respectively, the voltage amplitudes

U (t) _{100 Hz} , U (t) _{200 Hz} , U (t) _{300 Hz} , etc.

Analysis of the magnitudes of the amplitudes shows that for the correct operation of the generator, i.e. increasing its efficiency, it is necessary to fulfill inequality

.

.

To fulfill this inequality, it is sufficient to reduce the amplitudes

U _{m (100 Hz)} and U _{m (200 Hz)} .

SECOND STATE OF THE GENERATOR SCHEME

Connect between the first and second nodes of the bridge (figure 1) a serial circuit, which is formed by a capacitor 2, an inductor 3 and an additional resistor 5.

Using this circuit, the amplitudes U _{m (100 Hz)} and U _{m (200 Hz) are} reduced by a factor of K, while the oscillatory circuit is tuned to resonance at a frequency F ₀ = 150 Hz.

We define the expression for an additional resistor r _g , which is included in the circuit (in figure 1, position 5)

Where

- r _Σ active resistance of the oscillatory circuit at the resonance frequency F ₀ ;

- r _to - the active resistance of the air coil inductance of the oscillatory circuit, which is equal to

Where

- F ₀ = 150 Hz is the resonant frequency of the circuit;

- Q _k = 10 the quality factor of an air inductor, which is wound with a copper wire. The value of Q _{k is} determined from experience;

- L inductance of the air inductor (in figure 1, position 3).

To determine the numerical value of L, we will set the value of the capacitance of the capacitor of the circuit to calculate (in figure 1, position 2)

- Taking into account (4), we determine the numerical value of L

- Determine the active resistance of the coil r _to taking into account (5) when Q _to = 10

Where

L = 11.3 · 10 ^-3 Hg from (5);

F ₀ = 150 Hz from the frequency response of the oscillatory circuit (figure 2).

Q _to - determined empirically.

Figure 2 shows the frequency response of a sequential oscillatory circuit, while the frequencies of 100 Hz and 200 Hz are located at the edges of the bandwidth of the circuit ΔF, which is equal to ΔF = 200-100 Hz

- Determine the necessary value of the quality factor of the circuit Q _(k) (from figure 2):

From (7) it follows that the quality factor of the circuit is small, therefore, it is necessary to include an additional resistor r _g in the oscillatory circuit according to (2).

- Determine the total resistance of the oscillatory circuit r _Σ at a frequency F ₀ :

where L = 11.3 · 10 ^-3 H from (5);

C = 100 · 10 ^-6 F from (4);

Q _(k) = 1.5 from (7).

We determine from (2) the value of the additional resistor r _g , which must be included in the oscillatory circuit in order to roughen its frequency response:

Where

r _Σ = 7 Ohms from (8);

r _k = 1 Ohm from (6).

- Determine the relative detuning δ of the frequencies F ₁ and F ₂ relative to the resonant frequency F ₀ [L3]:

*

*

*) When F ₂ = F ₀ = 150 (resonance mode)

δ = 0, then from (11), the impedance

r _p = r _Σ = 7 Ohms, i.e. the farther from resonance, the r _{p is} greater.

- Define the impedance r _p . (F ₁ , F ₂ ) sequential oscillatory circuit at frequencies F ₁ = 100 Hz, F ₂ = 200 Hz

Where

r _Σ = 7 Ohms from (8);

Q _(k) = 1.5 from (7);

δ = 0.33 from (10).

- Determine the amplitude values of the voltages U _{m (100 Hz)} and U _{m (200 Hz)} after installing a sequential oscillatory circuit:

after installing the oscillating circuit

Thus, we reduced the values

U _{m (100 Hz)} and U _{m (200 Hz)} K = 9 times.

- We will verify the fulfillment of the CRITERIA, in which an oscillatory process will occur in a series oscillatory circuit, for which it is necessary to ensure that

9 <21.2 - THIS CRITERION EXECUTED

Where

r _p (F ₁ , F ₂ ) = 9 Ohms from (11);

L = 11.3 · 10 ^-3 Hg from (5);

C = 100 · 10 ^-6 F from (4).

Thus, after installing the circuit, the inequality that is necessary for the correct operation of the generator is satisfied:

Taking into account (15), one can neglect the values of the amplitudes of harmonics of 100 Hz, 200 Hz, 300 Hz, etc. due to their smallness compared to U _p = 200 V and assume that between the first and second nodes of the bridge there is only a constant component U _p = 200 V.

THIRD STATE OF THE GENERATOR DIAGRAM

Consider the operation of the generator when the pulses U (t) _control come to the information input of the key (Fig. 1, position 6).

ключ замкнут (16)

key locked (16)

ключ разомкнут (17)

key open (17)

where U _par . - the amplitude of the control pulses. Next, the process is repeated.

When the key is switched with a frequency f ₀ and the potential of Phase 1 is higher than the potential of the "Earth", a current is introduced into the 220 V line along the circuit: (Fig. 1)

Phase 1 - diode D ₁ - node 1 - load resistor of the generator 4 - controlled key 6 - node 2 - diode D ₃ - "Earth" (transformer neutral 10 / 0.4 kV, which is grounded).

Thus, taking into account (16) and (17), we express the time dependences for the currents passing through the resistor 4:

Next, the process is repeated.

Where R is the resistance value of the load resistor of the generator (figure 1, position 4).

We expand (18) in a Fourier series [2]

In this expansion in the Fourier series, we are interested in the signal current with a frequency of ω ₀ , i.e. FIRST HARMONIC DECOMPOSITION i (t), which is the signal current

where R is the resistance of the load resistor of the generator;

- амплитуда тока сигнала;

- the amplitude of the signal current;

ω ₀ = 2πf ₀ is the angular frequency.

SELECTION OF THE RANGE OF OPERATING FREQUENCIES f ₀

It is known that the main obstacles in the transmission of signals over power lines in the tonal frequency range are the odd harmonics of the frequency F = 50 Hz of the supply voltage, which decrease with increasing number of harmonics. At a frequency above 13 kHz, the harmonic voltage is comparable with fluctuation noise, which is significantly smaller in magnitude than the frequency harmonics F = 50 Hz.

PROTOTYPE cannot operate at frequencies above 3000 Hz due to the occurrence of wave processes due to the long line lengths of 10-35 kV.

, при этом должно выполняться условие220 V lines have an average length of l = 3 km at the speed of wave propagation in overhead lines

, while the condition

- Define, taking into account (21), the upper limit of the frequency range:

Where

- среднестатистическое значение скорости распространения волны по воздушным линиям 220 В;-

- the average value of the wave propagation velocity over the air lines of 220 V;

- волны;

- waves;

- l = 3 km - the average line length of 220 V;

- f ₀ - operating frequency in the communication channel.

Thus, we will accept the frequency range for operation in low-voltage lines 220 V

- From (22) we determine the operating frequency band ΔF (f ₀ ):

- Determine the minimum duration of the radio pulse in this band, given (23):

Note:

Note that the minimum duration of the radio pulse in the prototype is τ _{u (prot)} = 0.02 s, because a decrease in τ _{u (prot)} leads to an expansion of the emission band, which is equal to

This is due to the presence of odd harmonic interference at a frequency of 50 Hz, which are located at 100 Hz and have large levels of interference voltage.

We determine the maximum signal transmission rate in 220 V networks, taking into account (24)

- Determine how many times the signal transmission speed is increased in the APPLIED TECHNICAL SOLUTION, given that in the prototype the maximum signal transmission rate is 50 Bit / s

Due to the fact that in the frequency range above 13 kHz there is no harmonic interference, we will accept, based on experimental data, the signal current values through the generator load resistor equal to:

Where

where the value of I _{m. 0 is} defined in (20).

- From (28) we determine the value of the load resistor of the generator

- We determine from (28) the effective value of the signal currents

- Determine, taking into account (29) and (30), the power loss in a passive type generator

We neglect all other losses in connection with their smallness in comparison with P _p .

Note:

Despite the fact that the losses in the passive type generator are smaller than in the prototype, we will not do the comparison, because the prototype transmits signals along the (0.38-10-35) kV lines, and a generator that implements the claimed technical solution transmits signals only through 220 V networks, so the comparison will be incorrect.

Thus, we have proved that the goal set by the invention, to increase the transmission speed of signals compared to the prototype, is proved and amounts to an increase in the transmission speed of signals 100 times, the amplitudes U _{m (100 Hz)} and U _{m (200 Hz)} in K are also reduced times, where for the selected parameters of the elements of the circuit sequential oscillatory circuit K = 9.

Literature:

1. Tsagareishvili S.A., Gutin K.I. The theoretical basis for constructing a channel-forming device at tonal frequencies on electric networks of 0.4-35 kV. Journal "Science and Technology in Industry", No. 2 (5), Moscow, 2001, pp. 55-56.

2. Bronstein I.N., Senedyaev K.A. Handbook of higher mathematics for engineers and students of technical colleges, Moscow, Gostekhizdat, 1961, pp. 554-555.

3. Atabekov G.I. Theoretical Foundations of Electrical Engineering, Moscow, "Energy", 1966, pp. 69-74, p. 242.

Claims (1)

A device for inputting signal currents to a low voltage line 220 V at a frequency of 50 Hz, containing phase 1, a transformer neutral 10/0, 4 kV, which is grounded, a half-wave bridge assembled on diodes D ₁ , D ₂ , D ₃ , D ₄ , while the cathodes of the diodes D ₁ and D _{2 are} connected to the first node and the first terminal of the first resistor, the second terminal of which is connected to the terminal of the movable contact of the controlled key, the second terminal of which is connected to the second node and anodes of the diodes D ₃ , D ₄ , the cathode of the diode D ₄ and the anode the diode D ₁ is connected to a third node, neutral transformer 10/0 to 4 connected to the fourth node, and connected respectively to the cathode of the diode _D3 and the anode of the diode D _2, characterized in that the incorporated capacitor, inductor and second resistor, wherein the phase 1 is connected to a third node, the first plate of the capacitor is connected to the first node, the second plate of the capacitor connected to the first terminal of the inductor, the second terminal of which is connected to the first terminal of the resistor, the second terminal of which is connected to the second node.

Images