SU1108603A1 - Automatic voltage control device for rectifier-inverter converters of traction substations - Google Patents

Abstract

AUTOMATIC VOLTAGE REGULATION DEVICE FOR REFERENCE-INVERTER TRACTOR SUBSTITUTIONAL TRANSFORMERS, containing a transformer with a sectional winding, two controlled reactors, the first of which is connected with an extreme section of the winding section, an Icing panel, I have an X-ray pattern, 15 and 15 and 15 Ie, 14 Ie, 15 connected to the control circuits of the first and second reactors, the phase angle sensor of the current and voltage, connected to one of the inputs of the first comparison unit, and the sensor rectified voltage connected to one of the inputs of the second comparison unit, characterized in that, in order to expand the functional capabilities and improve reliability of regenerative braking, the device is equipped with a current correction unit, a correction unit for alternating voltage, a current sensor, a supply voltage sensor mains, a super current sensor, included in the cathode circuit of the inverter, a logical switching unit, an OR logic circuit, a NOT logic circuit, two threshold elements, two units and pulse-phase control, wherein the output of the Current sensor is connected to the first input of the current correction unit and the output of the supply voltage sensor is connected to the first input of the correcting block by alternating voltage; the other two inputs of the correcting block are connected to the output of the master unit; another input of the second comparison unit, and the output of the correction unit is alternately connected to another input of the first comparison unit; in addition, the output of the current sensor is connected Through the first threshold element to one of the inputs of the logic circuit OR, the output of the rectified voltage sensor is not connected to the second input of the LW logic circuit through the second threshold element and the logic circuit, and VYSAR the logic circuit OR connected to one of the inputs of the logic switching unit the other input of which is connected to the output of the discontinuous current sensor of the inverter, the first output of the logic switching unit is connected to the input of the master unit, and the second and third outputs are connected to the pulse-phase blocks control, respectively, of the inverter and rectifier, while the logical switching unit consists of a flip-flop, the inputs of which are the inputs

Description

this block, the logic circuit NOT, and two delay lines, the trigger output, which is the first output of the logic switch block, is simultaneously connected to the delay lines to one directly, and to the other through the logic circuit NOT, the output of the first one is and the output of the second - the second output of the logical switching unit.

The invention relates to voltage regulation and can be used on rectifier-inverter converters of traction substations of main-line railways with excessive energy recovery.  It is known a device that implements a method of voltage regulation at a traction substation, in which voltage is stabilized at various Tpe6yeNB X levels depending on the specific train situation at the inter-station area 1 However, this device cannot be used for voltage regulation on the sections of electric railways with regenerative braking of electric rolling stock, since its use does not fulfill the requirements imposed on the power supply system to ensure adezhnogo receiving recovery currents that is caused by the presence of high voltage substations, busbar of resetting the traction load T E and difficult to identify conditions in t govo network.  The closest to the invention according to the technical essence is the Yci automatic voltage regulation for rectifier-inverter converters of traction substations, which contains a transformer with a sectioned winding, two controllers of 1x reactor, the first of which is connected to the extreme terminal of the transformer winding and the second - with its tap, driver unit, two comparison units, the first of which is connected to the control circuits of the first, and the second to the second reactor, the sensor of the phase angle of the current and voltage connected to one from the inputs of the first comparison unit, and the rectified voltage sensor connected to one of the inputs of the second comparison unit G2.  However, this device has insufficient functional capabilities, since it only allows to obtain the characteristics of converters stabilized at different levels and cannot be used to regulate the voltage in areas with regenerative braking of electric rolling stock due to the fact that the presence of high voltage when substation buses reset the load current of the converters, the range between the allowable voltage on the pantograph of the electric locomotive and the voltage in the traction network, when which begins to recover, as well as to the occurrence of inrush current and voltage when switching converters to the corresponding operation modes and to the appearance of large equalizing currents between the converters.  The aim of the invention is to extend the functionality and increase the reliability of regenerative braking on sections of electric railways with automatic regulation of the voltage on the traction. substations x.  The goal is achieved by the fact that the known automatic voltage control device for rectifying-inverter converters of traction substations is additionally equipped with a current correction unit, a correcting unit for alternating voltage, a current sensor, a voltage sensor of the supply network, a discontinuous current sensor included in the cathode Inverter, logical switching unit, OR logic, NOT logic, two threshold elements.  two blocks of pulse-phase control, with the output of the current sensor connected to the first input of the current correction unit and to the first input of the correcting block by alternating voltage — the output of the supply voltage sensor; the other two inputs of the correcting blocks are connected to the output of the master unit, the output current the corrective unit is connected to another input of the second comparator unit, and the output of the corrective unit is alternately connected to another input of the first comparator unit, in addition, the current sensor output connected via the first threshold voltage (the element to one of the input logic circuit OR, to the second input logic circuit OR through the second threshold element and the logic circuit, the output of the rectified voltage sensor is NOT connected, and the output of the logic circuit OR is connected to one of the logic inputs the switching unit, to another input of which the output of the inverter current sensor is connected, the first output of the logic switching unit is connected to the input of the master unit, and the second and third outputs are connected to the pulsed-phase units respectively, the inverter and the terminal, the logic switching unit consists of a trigger, whose inputs are the inputs of this block, a logic circuit NOT and two delay lines, the trigger output, which is the first output of the logic switching unit, simultaneously connected to the delay lines are connected to one directly, and to the other through the logical circuit NOT, the output of the first one is the third, and the output of the second is the second output of the logic switching unit.  FIG.  1 is a block diagram of an automatic voltage regulation device for a rectifier-invertor converter; FIG.  2 shows the external characteristics of a voltage regulating converter; FIG.  For, b are timing diagrams for the operation of the device during the transition of the converter, respectively, in the inverter and terminal mode of operation. The automatic voltage regulator for the inverter transformer of the traction substation contains a converter transformer 1, the secondary winding of which is connected to the input of the three-phase bridge rectifier ITEL 2 and the output of the bridge inverter 3.  The input of the inverter 3 is through the current-limiting reactors 4 and 5, and the output of the rectifier 2 is directly connected to the DC stations of the substation.  The control of the rectifier 3 and the inverter 3 is carried out by the pulsed-phase control units 6 and 7, respectively.  The primary winding of the transformer 1 is made sectionalized, to the extreme outputs of which a three-phase control reactor 8 is connected, and to the outlets - a similar reactor 9.  The control circuits of the first 8 and second 9 controlled reactors are connected to the inputs of the first 10 and second 11 comparison blocks, to one of the inputs of each of which are connected the outputs of the sensor 12 of the phase angle of the current and voltage and the sensor 13 wives accordingly.  The output of the current sensor 15 is connected to the first input of the current correcting unit 14 and to the first input of the correcting unit 16 by alternating voltage - the output of the sensor 17 of the supply voltage.  Two other corrective blocks 14 and 16 are connected to the output of the master block 18.  The output of the current correction unit 14 is connected to another input of the second comparison unit 11, and the output of the correction unit 16, by alternating voltage, is connected to another input of the first comparison unit 10.  The output of the current sensor 15 is connected via the first threshold element 19 to one of the inputs of the logic circuit OR 20, to the second input of which, through a serially connected logic circuit HE 21 and the second threshold element 22, is connected to the output of the transient voltage sensor 13.  The output of the logic circuit OR 20 subfc keys to one of the inputs of the logical switching unit 23, to the other input of which is connected the output of the 24 precursor current sensor 24 included in the cathode of the inverter 3.  Logic switching unit 23 is complete on trigger 25, the output of which goes to the inputs of the master unit 18 and the first delay line 26 directly and to the input of the second delay line 27 via the NOT 28 logic circuit. The outputs of the first 26 and second 27 delay lines are connected respectively to the first 6 and the second 7 pulsed-phase blocks. control converters.  The automatic voltage regulator of the rectifier-inverter converter operates as follows.  The regulation is performed by two controlled reactors 8 and 9 by changing their reactance, as a result of which the primary current of the transformer 1 is redistributed between the tapes of the connected reactors.  A change in the magnetic flux of a transformer causes a corresponding change in the voltage on its secondary windings connected to the converters, and makes it possible to obtain the required external output characteristics of the rectifier U t (3) and the input characteristics of the IISF).  2) where the inverter Uj is the DC voltage, the inverter current is the rectifier. The reactance change of the reactors is produced by control signals acting on the control of the reactor circuit 8 and 9 and coming from the outputs of the corresponding comparison units tO and 11.  The control signals from the comparison units are formed depending on the magnitude of the mismatch between the driving signals from the correction blocks 14 and 16 and the signals of the corresponding current shear angle and voltage sensors 12 and rectified voltage 13.  In the inverter mode of operation, the most favorable characteristic is the horizontal characteristic 29, set at the voltage level Ujj, which provides the allowable voltage on the pantograph of an electric locomotive over the entire operating current range (Fig.  2).  Such a characteristic is achieved by a pulse-phase control unit 7, and the setting of the required stabilization level of the characteristic is determined by the master unit and carried out by controlled reactors.  Dp maintaining a higher energy performance of the inverter, it is possible to compound the input characteristic taking into account the minimum possible from the point of view of stability of the inverter advance angle, and the automatic voltage control system takes the horizontal characteristic and ensures the required level.  In the zone between the two extreme natural characteristics 30 and 31, the automatic control device allows to obtain external characteristics of the form 32 with a linear output with stabilization at currents lower than the output current to the stabilization mode Del at any desired level J d between the characteristics with a minimum of 33 and maximum FOR levels of stabilization (FIG.  2).  The level of stabilization of the characteristics in the acceleration mode, as well as in the inverter mode, is set by the master unit 18, the signals of which through correction blocks 14 and 16 are fed to the comparison circuits 11 and 10.  The voltage is stabilized under the action of the control signal from the second comparator block 11, which is formed by the mismatch at its input of the drive signal with the signal of the intermediate voltage 13.  In this case, the reactor control circuit 8, consisting of a comparison unit 10, a current shear angle sensor and a voltage 12, serves only to change the reactance of this reactor in order to obtain the highest values of power factor, this is done depending on a predetermined voltage level that is determined by the input signal of the block 18 arriving through the corrective block 16.  When „„ „stabilized characteristics are obtained in the range of operating currents that are large, the introduction through current corrections of block 14 of the signal from current sensor 15 makes it possible to reduce the static stabilization error at currents close to the nominal 2 Obtaining an output from stabilized characteristics in the rectifying mode is as follows.  When the discharge current is reset, the voltage to the value J „m -“ U I NOY 3-5l of the rated current J d you under the action of the signal from the Current sensor 15 there is a sharp increase in the gain of the current correction unit 14 so that.  the current is further reduced to zero, a linear (proportional to current) reduction of the rectified converter to the level is made. Since setting the required stabilization levels depending on the number of trains in the interstation station zone is done discretely, according to discretely set signals of the master unit 18, then each stabilization level by the current correction unit 14 the signals of the driver unit 18 establish its own, corresponding to this level, the gain necessary to ensure the output of external The transmitter has a set voltage level.  In order to eliminate the effect of voltage fluctuations in the supply network on obtaining these characteristics, a correction for the supply voltage is introduced into the automatic control device from the voltage sensor 17 through the correction unit 16.  Under the action of a signal from a variable voltage sensor 17, the correction unit according to alternating voltage 16 changes the signal arriving at its input from the master unit 18 so that it compensates for the effect of voltage fluctuations in the power supply network on the stability of the specified characteristics of the converters.  Switching the rectifier-inverter converter from one mode of operation to the other is performed without contact, removing and sending pulses to control the pulses of phase and phase control 6 and 7.  The signals for prohibiting the supply and removal of control pulses are formed in the logical switching unit 23, depending on the situation in the traction network, and are fed from its outputs 35 and 36 to the corresponding blocks 6 and 7 of the pulse-phase control.  At the same time, to set the law of regulation in accordance with the mode of operation, the driver unit 18 receives a signal from the output 37 of the logical switching unit 23.  The signal of the logical unit at this output corresponds to the rectifying mode and the signal of the logical zero to the inverter mode (FIG.  For, b).  The transition of a rectifier-inverter converter from the alternating mode to the inverter mode (FIG.  Z) is carried out by the signals of the current sensor 15 and the voltage sensor 13.  If the load current of the rectifier is greater than the setting current D ,. , even when the voltage is stabilized at a level higher than the pickup setpoint voltage U ,, the converter is not transferred to the inverter mode, since in this case the current blocking by logic unit signal at the output 38 of the threshold element 19 is applied through the OR circuit 20 .  When the load current is reset below, the voltage is reduced by the control device, and when the voltage level drops below U at time 1, a voltage lock is applied and the output 39 of the threshold element 22 produces a logic zero signal which is inverted through the logic circuit. 21 enters from its output 40 in the comparison unit 20 (FIG.  Behind).  With a further decrease in current and voltage, when the current reaches the setpoint 3, the current blocking is removed (the logic zero signal at the output 38 of the threshold element 19) at time tj. The next decrease in the current to zero leads to a decrease in the voltage of the converter to the level Ujj, and the idle mode comes up.  With the appearance of excess energy recovery, the voltage level in the contact network increases.  When at a unit current equal to zero, the voltage in the contact network rises to the level K, at time tj, the voltage blocking is removed (the signal of the logic zero at the output 40 of the HE 21 logic circuit), and the output 41 of the I1Sh 20 circuit appears - zero, switching the trigger 25 and giving the command to the logical switching unit 23 to transfer the unit to the inverter mode.  At the same time, logical unit signals appear at outputs 35 and 37, which, without a time delay, command to remove the control pulses from the rectifier to the CMF unit 6 and to reversal the controlled reactors in accordance with the law of the inverter control to the driver unit 18 .  With a time delay l (at the moment 1, the delay line 27 carried out by the signal from the logic circuit 28 at the output 36 of the switching unit 23 appears the signal lo- the.  unit, under the action of which the pulsed-phase control unit 7 supplies control pulses to the inverter thyristors.  The settings for the transition of the unit to the inverter relaiN are selected from condition 0.  for pore element 19 and t ,. jg (| - for element 22.  To achieve the correct and smooth switching of the converter, it is necessary to achieve the smallest setting E.  , since the voltage of the linear part of the external characteristic 34 depends on it at the output from the highest possible level of stabilization of the outlets. Switching the converter from the inverter mode to the rectifying mode (Fig.  36) is produced by the signal from the discontinuous current sensor of the inverter 24, the operation of which is described in detail 33.  When the moment of reliable locking of the inverter thyristors is reached at the moment t; ending the river operation (fig.  36) At the output 42 of the discontinuous current sensor 24, a logic zero signal appears, which is fed to the first input of the logic switching unit 23 and switches the trigger 25 to the position corresponding to the hot mode of the converter.  Under the action of the signal from the output 36 of the block 23 (Logical zero signal), the pulse-phase control unit 7 removes the control pulses from the inverter thyristors.  At the same time the signal from the output 37 of the logical switch. unit (signal of the logical unit) switches the automatic control device to the voltage regulation law required for the rectifying mode of the converter operation. With delay, the magnetization reversal of controlled reactors by the delay line 26 is delayed, the output of the unit 23 is the signal of the logical unit (in time i), under the action of which the pulsed-phase control unit 6 delivers control pulses to the rectifier thyristors.  The use of the invention allows to provide regenerative braking of electric rolling stock and increase its reliability in areas with voltage regulation in the traction network.  At the same time, technical and economic efficiency is achieved by increasing energy savings due to increasing the reliability of the rectifier on the inverter inverter and speed of operation during transitions from mode to mode, as well as eliminating power losses by reducing equalizing currents between converters. when adjusting the voltage and accuracy of determining situations in the traction network.

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Claims (1)

DEVICE FOR AUTOMATIC VOLTAGE REGULATION FOR RECTIFIER-INVERTER CONVERTERS OF TRACTION SUBSTATIONS, containing a transformer with a sectioned winding, two controlled reactors, the first of which is connected to the terminal end of the transformer winding, and the second, from which the unit is connected from with control circuits of the first and second of the second reactor, a phase angle sensor for current and voltage, connected to one of the inputs of the first comparison unit, and a rectified voltage sensor voltage, connected to one of the inputs of the second comparison unit, characterized in that, in order to expand the functionality and improve the reliability of regenerative braking, the device is equipped with a current correction unit, an AC voltage correction unit, a current sensor, a voltage sensor of the supply network, a sensor intermittent * current included in the cathode circuit of the inverter, a logical switching unit, an OR logic circuit, a NOT logic circuit, two threshold elements, two pulse phase units control, and the output of the current sensor is connected to the first input of the current correction unit and the voltage sensor output of the mains voltage is connected to the first input of the correction unit, the other two inputs of the correction blocks are connected to the output of the master unit, the output of the current correction unit is connected to another input of the second unit of comparison, and the output of the correcting unit for alternating voltage is connected to another input of the first unit of comparison, in addition, the output of the current sensor is connected through the first threshold e the element is connected to one of the inputs of the OR logic circuit, to the second input of the OR logic circuit, through the second threshold element and the logic circuit, the rectified voltage sensor output is NOT connected, and the output of the OR logic circuit is connected to one of the inputs of the logical switching unit, the sensor output is connected to the other input discontinuous current of the inverter, the first output of the logical switching unit is connected to the input of the master unit, and the second and third outputs are connected to the pulse-phase control units, respectively, invert and a rectifier, while the logical switching block consists of a trigger, the inputs of which are the inputs of this block, a logic circuit NOT, and two delay lines, and the output of the trigger, which is the first output of the logical switching block, is simultaneously connected to the delay lines - to one directly, and to the other, through the logic circuitry NOT, the output of the first one is the third, and the output of the second is the second output of the logical switching block.