SU1481827A1 - Unit for teleprocessing along wires of three-phase electric network - Google Patents

Abstract

The invention relates to telemechanics and can be used to control consumers through wires of a three-phase electrical network. The purpose of the invention is to improve the reliability and noise immunity of the device when operating in the ground-to-ground mode in the supply network. The device contains a transmitting half-set 1, consisting of a generator of transmission zone 2, element I 3, modulator 4, power amplifier 5, transmitter 6, isolation control unit 7, delay block 8, coding unit 9, switch 10 of the operating mode of the amplifier

receiving half set 11 consisting of receiver 12, first threshold element 13, first delay 14, first memory 15, second delay 16, OR 17, second threshold 18, demodulator 19, And 20, decoder 21 , the second memory element 22, the former of the reception area 23. The device allows to ensure reliable operation of the controlled consumers in the closing mode in the power supply network. 1 il.

Description

The invention relates to telemechanics and can be used to control consumers, such as electric heaters, through a three-phase 0.38 kV electrical network to which heaters are connected.

The purpose of the invention is to improve the reliability and noise immunity of the device for telecontrol in the presence of a ground fault in the supply network.

The drawing shows a block diagram of the proposed device.

The device contains a transmitting half-set 1 consisting of a generator 2 of the transmission zone, an OF element, a modulator 4, a power amplifier 5, a transmitter 6, an isolation control unit 7, a delay unit 8, a coding unit 9, an amplifier operating mode switch 10, a receiving half 11 consisting of

communications and home radio equipment.

However, when a ground fault condition occurs in a 10 kV mains supply, accompanied by arc processes at the point of closure, the level of fluctuation disturbances in the 0.38 kV mains increases by 5-6 times that

Yu leads to the exceeding of this level over the first triggering threshold of the second threshold element 18 and to the failure (for the time of the earth fault) of the communication channel 15. In view of the fact that the earth fault mode can exist in rural electrical grids 10 kV hours, and sometimes for days, it is necessary to ensure reliable operation of the communication channel and, consequently, reliable operation of controlled consumers. To do this, a block 7 of the test receiver 12, a first threshold insulator of 25 liters of isolation, fixing the presence of the specified mode in a 10 kV network, and a delay block 8, are introduced into the transmitting half-set 1 installed at the TP 10 / 0.4 kV. If a ground fault condition occurs in a 10 kV network, the device 7 controls the insulation, sub 13, the first delay element 14, the first memory element 15, the second delay element 16, the 10 kV network mode, and the delay block 8. In the event of a ground-close mode in a 10 kV network, the device 7 for the isolation control, the OR 17 substitute, the second

element 18, demodulator 19, elemental to the wires of the 10 kV network,

And 20, the decoder 21, the second element, supplies a signal to the delay unit 8, s

22 memory, the former 23 reception areas.

The device works as follows., With

For the transmission of telecontrol signals by consumers connected to the wires of the three-phase electric network 0.38 kV, as communication lines

the output of which is fed to the first input of the coding block 9 and through the block | 0 to the control input of the power amplifier 5, switching its gain factor and increasing the amplitude of the transmitted signal by 8-10 times. At the same time, the coding unit fulfills the signal. The closure does not use the wires of the indicated earth ground with an increased amplitude in the 0.38 kV lithic network. When choosing the power and amplitude of the telecontrol signal, attenuation of the signal in the line and the level of fluctuation noise are taken into account so that at the most distant point of the network the signal level exceeds the level of fluctuation noise by 3 to 4 times (depending on the required level of information transmission confidence).

In accordance with the minimum signal level, the threshold for triggering the threshold element 18 of the receiving half-kit is selected. This approach ensures the use of low-power signals with small amplitudes, which allows to ensure minimal interfering effects of telecontrol signals on other media45

50

55

connection.

At the receiving end of the line, two variants of the circuit operation are possible, depending on whether the level of fluctuating noise in the 0.38 kV network is raised directly at the first moment of the ground-fault mode in the 10 kB network. When the level of fluctuation noise is raised above the first threshold of the second threshold element 18 and accordingly above the threshold of the first threshold element 13, whose threshold is chosen to be slightly lower, the signal goes to the input of the delay element 14 and then goes to the control input of the memory element 15, output signal which through the element OR 17 switches the threshold of the second

communications and home radio equipment.

However, when a ground fault condition occurs in a 10 kV mains supply, accompanied by arc processes at the point of closure, the level of fluctuation noise in the 0.38 kV grid increases by 5-6 times, which is

leads to exceeding this level over the first threshold of triggering the second threshold element 18 and failing (for the duration of the earth fault) of the communication channel, "Due to the fact that the earth fault mode can exist in rural electrical networks 10 kV hours and sometimes day, it is necessary to ensure reliable operation of the communication channel and, consequently, reliable operation of controlled consumers. To do this, an isolation control unit 7, which records the presence of the specified mode in a 10 kV network, and a delay unit 8, are introduced into the transmitting half-set 1 installed on a 10 / 0.4 kV transformer substation. If a ground fault condition occurs in a 10 kV network, the device 7 of the insulation control, under 5

0

five

connection.

At the receiving end of the line, two variants of the circuit operation are possible, depending on whether the level of fluctuating noise in the 0.38 kV network is raised directly at the first moment of the ground-fault mode in the 10 kB network. When the level of fluctuation noise is raised above the first threshold of the second threshold element 18 and accordingly above the threshold of the first threshold element 13, whose threshold is chosen to be slightly lower, the signal goes to the input of the delay element 14 and then goes to the control input of the memory element 15, output signal which through the element OR 17 switches the threshold of the second

element 18, increasing it 8 - 10 times (this increase should not be greater than the increase in the gain of the amplifier 5 power). The delay time of element 14 (Ј) is determined on the basis of a possible short-term increase in the level of fluctuations during normal operation of the network and is 4-5 periods of power frequency voltage. Due to the fact that the delay time of block 8 (выбира,) is selected as Cr + Ј, where d is the time required to send the elements 15 and 17 and set the second threshold of the element 18, the Closure to ground signal (if there is a signal) reliably receives the receiver 12 and from the second output of the decoder 21 are fed to the control input of the second element 22 Memory, from the output of which, through the OR element 17, the signal ensures the operation of the second threshold element 18 with the second response threshold. Thus, the channel is ready for operation under the conditions of the ground fault in the 10 kV mains supply, with the elimination of which the transmitter isolation control unit 7 processes the corresponding signal, which through the delay unit 8 arrives at the first input of the encoding unit 9, which fulfills the signal . In order for this signal to be reliably received by the receiving half 11, the power amplifier 5 returns to normal gain after the time Ј4 of operation of the amplifier mode switch 10, which is chosen equal to the transfer time of the Failover code pattern, as amplifier A slowdown relay may be used.

After this signal is received by the receiving half 11, the third output of the decoder 21 sends a signal to the reset input of the memory element 22, and the second threshold element 18 returns to operation with the first trigger threshold.

In view of the fact that it is impossible to completely exclude the exceeding of the level of fluctuational noise above the threshold of the threshold element 13 for a short but longer time

without the occurrence of the ground-closure mode B of the 10 kV network, a delay element 16 is inserted in the receiving semi-kit 11, which, after time Ј4 after the appearance of the signal at the output of element 14, processes the signal arriving at the dumping ground of the first element 15 Memory. In this case, C is selected such that the receiving half 11 reliably recognizes the signal Closure to ground and, via elements 23 and 17, the second threshold of the second threshold element 18 is fixed ()

./X./V/ 1b.j

f-4 G-Z + Chsh bc2,

where D -2 is the time margin required to eliminate the Race situation.

After the signal arrives at the dumping input of the first element 15, the memory of the second threshold element 18 begins operation with the first triggering threshold.

Thus, the device allows to ensure reliable operation of controlled consumers in the presence of a ground fault in the supply network.

Claims (1)

Invention Formula A device for telecontrol over wires of a three-phase electric network containing a transmitting set consisting of a transmission zone forming unit, whose input is combined with the transmitter output and connected to electrical network wires, the output of the transmission shaping unit is connected to the first input of the And element, the output of which is through the modulator connected to the first input of the amplifier; the output of which is connected to the input of the transmitter; a coding unit, the first information input of which is the information input of the device; output The coding unit is connected to the second input of the element I, the receiving half set consisting of a receiver, whose input is combined with the input of the reception area forming unit and connected to the wires of the communication line, a demodulator whose output is connected to the first input of the element And, to the second input which is connected the output of the reception zone forming unit, the output of the element I is connected to the input of the decoder, the outputs of which are informational outputs of the device, characterized in that, in order to increase the reliability and noise immunity of the device when operating in the ground-close mode in the supply mains, isolation control unit, delay unit, amplifier operation mode switch, isolation control unit input is connected to the wires of the power supply network, and the output is connected to the second information through the delay unit the input of the coding unit and through the mode switch of the amplifier is connected to the second input of the amplifier, the first and second, respectively, threshold elements, delay blocks, and five 0 the memory elements, the OR element, the output of the receiver is connected to the input of the first threshold element and the first input of the second threshold element; the input of the first memory element, the output of which is connected to the first input of the OR element, the output of which is connected to the second input of the second threshold element, the output of which is connected to the input of the demodulator, the first control output A decoder is connected to the first input of the second memory element, the second control output of the decoder is connected to the second input of the second memory element, the output of which is connected to the second input of the OR element.