SU1427464A1 - Apparatus for protective disconnection of contact wire network - Google Patents

Abstract

The invention relates to electrical engineering and is intended to control the magnitude of the current. The leakage in the DC network to the pauses of the power supply. The purpose of the invention is to improve the energy performance and reliability of the device. The auxiliary thyristors 14 and 15 together with the thyristors 1, 6 of the controlled rectifier ensure its operation in the inverter mode due to the energy accumulated in the inductance of the 8 t network. Capacity 9 tons of govt net at.

Description

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with

tSue.f

this is charged with polarity plus on the plate connected to the anodic group of thyristors 2,4,6 rectifier 7. The discharge resistor 21 and the discharge diode 22 provide fast discharge; capacitance 9, after which the current in the sensor 18 changes your direction. The voltage on the sensor 18 determines the magnitude of the leakage resistance 10. In this case, the network capacity 9 does not affect the measurement process of the leakage resistance 10. In the event that the leakage resistance 10 is below the allowable, the device blocks the opening of the controlled rectifier 7 until the leakage resistance 10 becomes acceptable and the formation thyristor voltage 14,15 will continue with a certain frequency. The invention makes it possible to check the leakage resistance and automatically restore the power supply after the resistance has been restored without the use of an additional source of operating voltage. 3 il.

The invention relates to electrical engineering, in particular, to devices for protective disconnection from current leaks in a direct current shaft contact network with periodic interruption of a load circuit by means of a controlled rectifier.

The purpose of the invention is to improve the energy performance and reliability of the device,

Figure 1 shows the diagram of the device; FIGS. 2 and 3 are diagrams of signals at the outputs of elements constituting the proposed device, which clarify its operation,

The thyristors of the power controlled voltage of the sensors 7 transform the three-phase alternating voltage into a constant voltage connected to the traction network. Distributed inductance, capacitance and leakage resistance of the traction network are represented respectively by the elements 8.9, and 10, With the traction network through the veins

tilny zagraditel 11 connected load

25

12, covered by the buffer diode 13. The line voltage supplying elements of the AC are connected to the formation of the operating voltage: a thyristor 14 connected by an anode with a positive terminal of the rectifier 7, and a thyristor 15, the cathode of which through series-connected voltage stabilizer 16 , the first cut-off diode 17, connected according to the flow of the operating current 35, and the sensor 18 of the operative

current, made in the form of a resistor, is connected to the negative pole of the rectifier 7, Element, 19 of the reference voltage of the stabilizer 16 through the second cut-off diode 20 is connected to the positive pole of the rectifier 7, to which is connected through the discharge resistor 21 and the discharge diode 22 the junction point of the first cut-off diode 17 and the operating current sensor 18, the bit 22 and the cut-off 20 diodes being turned on opposite to the rectified voltage. The operational current sensor 18 is enclosed by a series-connected limiting resistor 23 and a threshold element at the Zener diode 24. Parallel to the latter, the input of the sensing organ 25 connected to the first input of the MEMORY element 26 is connected, the second input of which is connected to the output of the selector pulse former 27.

The inputs of the selector pulse shaper 27 are connected to the outputs of the frequency divider 28, made in the form of a shift register, and the second output of the pulse shaper 29 connected to the frequency divider 28 by the first output, and the inputs to the alternating supply voltage. The output of the element 26 MEMORY is associated with the input of the inverter 30 and the first input of the element 31 2I-NOT connected by the second input to the output of the frequency divider 28.

The outputs of the element 31 2I-NOT, the inverter 30 and the splitter 28 frequency through amplifiers 32 - 34 with galvanic isolation of output. the signals are connected, respectively, with thyristor control elements 2-5, 1, 6 and 14.15,

The first input element 26 MEMORY associated with the output of the sensing organ 25 is connected to the first input element 35 2I-NOT, the output of which is connected to the first inputs of the RS flip-flop 36 and the second element 37 2I-NOT connected to the output of the second input There are RS-flip-flops 36. The second inputs of the elements 35 and 37. 2I-NOT are combined and are the second input of the MEMORY element 26, the output of which is the first output of the RS-flip-flop 36,

At the outputs of the pulse driver 29, the alternating network voltage is converted into a sequence of low and high unipolar signals. At the first output of the pulse driver 29 connected to the input of the frequency divider 28, a high-to-low signal transition occurs when the thyristor 1 of the cathode group of phase A and the thyristor 6 of the anode group of phase C of the controlled rectifier 7 are simultaneously flowing. For example, if the positive polarity of the linear voltage of the sun corresponds to a high level signal and the negative polarity of the specified voltage to a low level signal at the first output of the driver 29 of pulses. At the second output of the latter, a narrow low level signal is formed at the time of the occurrence of the negative polarity of the linear voltage AB,

Assume that until t

ten

15

The transducer 7, which feeds the load 12 through the valve barrier P, at a time t, the linear voltage of the sun goes into negative values and the high level signal is switched to low at the first output of the driver 29, which causes the splitter to appear 28 low level signals. The latter arrives at the first input of element 31 2I-NOT and blocks the flow of signals from the output of amplifier 33 to the control electrodes of thyristors 2-5, and also simultaneously through the output amplifier 32 provides signals to the control electrodes of thyristors 14 and 15. The amplitude of the positive half-wave of phase A and the negative half-wave of phase C exceeds the amplitudes of the voltages of the remaining phases of the alternating voltage and the thyristors 1 and 6 continue to conduct, the thyristors 2-5 close, and the thyristors 14 and 15 turn out to be prepared for dug, B result of a traction in the traction network, changes the linear voltage of the AC, If the load 12 is at significant distances from the rectifier 7, the latter due to the energy accumulated in the inductance 8 t of the traction network, at t goes into inverter mode (after passing through the linear voltage zero of the AC) and the output voltage of the rectifier 7 changes the sign to the opposite of the operating voltage of the mean voltage. In this case, the thyristors 1 and 6 rectifiers continue to conduct current -. 7, the longest possible duration of the inverter mode of the rectifier is 90 e, hail, (until the current drops in the traction network to

20

25

thirty

35

(Fig.2) at the output of the divider 28 often- - zero). After the end of the inverter

You and the MEMORY 26 element have high level signals, and, therefore, at the outputs of the element 31 2И-НА and the inverter 30 are low level signals. The latter, through the output amplifiers 33, 34, provide 6 control signals to the control, the thyristor electrodes, and a high level signal at the output

50

The mode of operation of rectifier 7 with a capacity of 9 t of the switch network is charged with polarity plus on the lining connected to the anode group of thyristors 2, 4 and 6-vypr mitel 7. If the voltage level on the capacitance 9 is higher than the operating voltage level, the flow of the operating current to measure the value of the frequency resistor 28 blocks the input leakage 10 g of leakage is impossible. Since the signals from the output of the amplifier 32, the capacity of the 9th traction network can be discharged to the control electrodes of the thyristors can only be circulated through the external circuit at 14 and 15. This ensures that the operating voltage is controlled

leakage resistance 10 (valve barrier 11 prevents leakage

five

The transducer 7, which feeds the load 12 through the valve barrier P, at a time t, the linear voltage of the sun goes into negative values and the high level signal is switched to low at the first output of the driver 29, which causes the splitter to appear 28 low level signals. The latter arrives at the first input of element 31 2I-NOT and blocks the flow of signals from the output of amplifier 33 to the control electrodes of thyristors 2-5, and also simultaneously through the output amplifier 32 provides signals to the control electrodes of thyristors 14 and 15. The amplitude of the positive half-wave of phase A and the negative half-wave of phase C exceeds the amplitudes of the voltages of the remaining phases of the alternating voltage and the thyristors 1 and 6 continue to conduct, the thyristors 2-5 close, and the thyristors 14 and 15 turn out to be prepared for dug, B result of a traction in the traction network, changes the linear voltage of the AC, If the load 12 is at significant distances from the rectifier 7, the latter due to the energy accumulated in the inductance 8 t of the traction network, at t goes into inverter mode (after passing through the linear voltage zero of the AC) and the output voltage of the rectifier 7 changes the sign to the opposite of the operating voltage of the mean voltage. In this case, the thyristors 1 and 6 rectifier continue to conduct. 7, the longest possible duration of the inverter mode of the rectifier is 90 e, hail, (until the current drops in the traction network to

0

five

0

five

 zero). After the end of the inverter

50

The mode of operation of rectifier 7 with a capacity of 9 t of the switch network is charged with polarity plus on the lining connected to the anode group of thyristors 2, 4 and 6-vypr mitel 7. If the voltage level on the capacitance 9 is higher than the operating voltage level, then the flow of the operating current to measure the magnitude of the leakage resistance 10 is impossible. Since the 9 t capacity of the govt network can be discharged through the external circuit only through

leakage resistance 10 (valve barrier 11 prevents leakage

the capacitive discharge current through the load, and the cut-off diode 17 through the operating voltage source), to accelerate its discharge is served by the discharge circuit consisting of the discharge resistor 21 and the discharge diode 22, the specified elements and the sensor 18 the operating current is quickly discharged into the 9t go-go capacitance tank to the voltage level of the operating source, after which the current in the sensor; 18 the operating current changes direction and the phase G flows through the circuit - the thyristor 15 - the voltage regulator 16 - the first cutting diode 17 -. operating current sensor 18 — leakage resistance 10 — thyristor 14 — phase A of the supply alternating voltage — jgeni. In addition, the current of the alternating current source flows through the diode 22 and the resistor 21 connected in parallel with the operational current sensor 18 and the leakage resistance 10 connected in series, thanks to the presence of the Stabilizer 16, the voltage at the output of which is determined by the element 19 of the reference voltage, the level of the operational voltage applied to the series-connected operating voltage sensor 18 and the leakage resistance 10 will be stable until the amplitude value decreases and line voltage AC below the level of stabilization of the element 19 of the reference voltage. Since the magnitude of the resistance of the operational voltage sensor 18 is constant, the level of the voltage generated on it is inversely proportional to the magnitude of the leakage resistance 10. The high level stability of the operating voltage, even with large values of leakage resistance 10, is ensured by the flow of current from the operating voltage source through the discharge diode 22 and resistor 21. At the same time, the flow of current through the indicated elements does not affect the accuracy of resistance measurement leakage, since it does not flow through the operating current sensor 18,

In the case when the load 12 in the traction network is missing or is located near the rectifier 7, the inverter mode of the latter is absent, and immediately after passing the measured voltage across zero

5 d g

g

five

thyristors 14, 15 (dot tio). The network capacity 9 at this charge is charged to the level of the operating voltage source and does not affect the measurement process of the leakage resistance 10 in the future.

In the inverter mode of operation of the rectifier 7, the charging of the capacitor 9 of the traction network from the operational source or a sharp decrease in the leakage resistance 10 on the operational current sensor 18, significant voltage levels are observed. To protect the input circuits of the sensing organ 25 from high voltages, in the above modes, a limiting resistor 23 and a threshold element 24 connected in series are connected in parallel with the operating current sensor 18. The signal from the output of the operating current sensor 18 through the limiting resistor 23 is fed to the input of the sensing organ 25. Changes in the output signal of the latter in transient modes do not cause a change in the state of the MEMORY element 26, since at the second input from the output of the selector pulse former 27 there is a blocking signal . After the termination of transient processes associated with the interruption of the current in the traction network and the application of an operational voltage to it, a narrow low level signal appears at the second output of the driver 29, the low level of two signals at the inputs the selector pulse shaper 27 leads to the appearance of a narrow high level signal at its output, which permits the reception of information by the element 26 MEMORY, since during this period the signal at the input of the sensing organ 25 depends only on the resistance value 10 oestrus then present at its output a signal of low or high level, respectively, indicating an invalid or a valid value of the resistance 10, a leak in the traction network. If a low level signal is present at the output of the sensing organ, then at the outputs of elements 35 and 37 2I-NOT, high signals are respectively set. and low levels, which causes the appearance on the first output of the RS-flip-flop 36, and consequently, on the output of the element 26 MEMORY g.ngnpl low

level The latter is fed to the first input of element 31 2I-NOT and to the input of element 30, and high-level signals at the outputs of these elements block the supply of control signals by amplifiers 33 and 34 to the control electrodes of thyristors 1-6, the controlled rectifier 7 which prevents the formation of an operating voltage until the point in time until the leakage resistance 10 becomes greater than the allowable value. The normalization of the operating voltage by the thyristors 14 and 15 will then continue with a frequency determined by the period of following the low level signals at the output of the frequency divider 28 (see Fig. 3).

If the output of the sensing organ 25 at the time of the appearance of the high level signal at the output of the selector imager 27, a high level signal is present, then the outputs of the elements 35 and 37 2I-NOT respectively set signals

low and high levels, which corresponds to the presence on the first output of the RS flip-flop 36, and consequently,

on the input of the element MEMORY 26 of a high level signal, which does not interfere with the operation of the device specified by the output signals of the frequency divider 28. When the selector pulses of a low level signal blocking the reception of information from the sensitive organ 25 by the element 26 MEMORY at the output of the elements 35 and 37 2I-NO, the output of the high level signals that do not affect the change of the RS flip-flop 36, and the latter saves the information received by the MEMORY element 26 from the output of the sensing organ 25 at ty until the next measurement point of the leakage resistance (t).

At time t6, the formation of the operating voltage stops, the thyristors 1.6 turn on (as there are control signals on the electrodes from the output of the amplifiers 34) and the formation of the operating voltage begins again. The latter, the age of the sinusoid, at t, reaches a value at which the voltage levels of the positive polarity of phase A and the negative polarity of phase C have a greater value, relative to other phases. At the same moment

0

five

0

ABOUT

Time, the linear voltage BC passes through zero to the region of negative values, which causes the next signal transition at the first output of the pulse shaper 29 from a high level to a low one, and consequently, a high level signal appears again at the output of the frequency divider 28. The latter blocks the flow of signals to the control electrodes of the thyristors 14 and 15 and allows the flow of signals to the control electrodes of the thyristors 2-5, which ensures the formation of the operating voltage by the rectifier 7. In this case, the cut-off 20 and discharge 22 diodes prevent current flow through the elements of the formation of operational voltage.

The decline and increase of the operating voltage by a sinusoidal law before and after the process is completed — the formation of an operational voltage to monitor leakage resistance contributes to the appearance in the traction network of a minimum level of high-frequency interference affecting the operation of the CCS.

The formation of the operating voltage by the switch 7 takes place up to the moment of time tg, during which the next transition of the signal at the output of the frequency divider 28 from a high level to a low occurs, and the processes described above are repeated. The longest time between two successive measurements of leakage resistance at a nominal voltage level in the 275 V supply network is 0.4 s.

five

Connecting auxiliary thyristors and synchronizing them to open allows, without the use of an additional source of operating voltage, before supplying the operating voltage to the traction network, carry out a preliminary check of the leakage resistance value and automatically restore the power supply of consumers after the leakage resistance recovers when it increases to a value greater than the specified one.

Due to the natural closure of auxiliary thyristors when changing the polarity of the supply voltage and turning on the second cut-off diode, the power consumption by the elements of the operational source is reduced to zero.

stress in the process of forming a working stress.

The inclusion of a parametric stabilizer with a controllable input will significantly reduce the internal resistance of the operating voltage source and thereby increase the accuracy of measuring the leakage resistance.

The inclusion of the first blocking diode, the discharge resistors and the diode according to the proposed scheme will make it possible to eliminate the flow of current of the discharge capacity of the network

And the current from the reactive component of the diode 15 °, connected by the cathode to

of the traction network through e-j eHTbi formation of operational voltage.

Claims (1)

Claim I A device for the protective disconnection of a direct current contact network {containing a power-controlled actuator connected in a three-phase bridge circuit, with the output terminal of the anode 1Py of the thyristors of the power controlled rectifier connected to the first output of the operating current sensor and the anode of the zener diode connected in parallel the input of the sensing organ, the second output of the operating current sensor is connected to the cathode of the first cut-off diode connected by ano-: with the output of a parametric stabilizer of the control voltage, the discharge resistor, the first output of which is connected to the cathode of the discharge diode, is synchronized with the supply voltage of the pulse driver, the first output of which through the frequency divider is connected to the first input of the driver of pulse pulses, and also the RS trigger, current-limiting - a resistor, a voltage reference element and the first auxiliary thyristor, characterized in that, in order to improve the energy performance and reliability of operation, a second cut-off diode is inserted into it, three elements that 2I-NOT, an inverter, three amplifiers and a second auxiliary thyristor connected by the anode to the output of the cathode group the thyristors of the power controlled rectifier, and the cathode to the output for connection to one of the phases of the alternating voltage source, to the output for connecting to the second phase of the alternating voltage source, the anode of the first auxiliary thyristor connected by the cathode to the input of the parametric operating voltage regulator, made with a control terminal, which is connected to the anode of the second cut-off device through the element of the reference voltage the output of the cathode group of the thyristors of the power controlled rectifier, to which the second output of the discharge resistor is also connected, and the anode of the discharge diode is connected to the second output of the operating current sensor, to which the first output of the current-limiting resistor is also connected, the second output of which is connected to the diode of the zener diode , with the second output of the pulse former connected to the second input of the selector pulse former, the output of which is connected to the first inputs of the first 0 and the second element 2I-NOT, the output of the sensing organ is connected to the second input of the first element 2I-NOT connected to the Z-input of the KZ-trigger and to the second input of the second element 2I-NO connected to the R-input of the KZ-trigger, the output of which is connected to the input of the inverter and the first input of the third element 2I-NOT, the output of the frequency divider is connected to the second input of the third element 2I-NOT and through the first amplifier to the control electrodes of the auxiliary thyristors, the output of the inverter through the second amplifier is connected to the control elec- delivery of two power thyristors controlled rectifier, which is incorporated opposite parallel br auxiliary thyristors and to the control electrodes of the thyristors remaining power controlled rectifier via a third amplifier connected to the output of the third NOR element 2I. five 0 five 0 ils willow .. Shp / s / ICE „Willow. Idv / / / Us %.../five FIG, g