RU1775799C - High-speed device for automatic change-over to reserve power supply of users with a motor load - Google Patents

Abstract

Into a device containing a phase-sensitive block 1 with three threshold outputs 12,13,14, two blocks 2 and 3 for measuring the time interval, two blocks 4 and 5 for converting the time interval, a memory unit 6, a summing and comparing unit 7. output body 8 and control unit for switches 9; angle lock is entered. The interlock is connected to the first 12 and third 13 threshold outputs of the phase-sensitive block 1 and contains a series-connected inverter 15, trigger 16, an NAND gate, an AND 18 logic gate. The outputs 10 and 11 of the phase-sensitive block 1 are connected to the consumer section with motor load and to backup power source. Switching to the backup power is performed in-phase with the residual voltage of the motors when the summing unit 7 is triggered and there are no blocking signals. If the operation of the summing unit 7 occurs with an invalid angle, then the operation of the output organ 8 will occur after the blocking signals are removed from the inputs of the AND gate 18.2 ill. e

Description

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The invention relates to devices for automatically switching on the backup power supply of consumers with a motor load involved in continuous technological processes.

A device is known for automatically turning on the backup power supply of consumers for substations with motor load, containing a starting and selective phase-sensitive organs, which selects the moment of switching on the backup power by counting the specified delay after reaching the angle 5 between the voltage vectors of the main and backup power sources of 270 ° ,

The closest in technical essence to the proposed is a device for common-mode automatic switching on of the backup power supply of consumers with a motor load, comprising a phase-sensitive unit with two inputs for connecting to a consumer section with a motor load and a backup power source and with three threshold outputs, the first and the second of which is connected to two inputs of the first time interval measuring unit with the output time conversion unit, and the first and third to two the inputs of the second measurement unit of the time interval, the output of which is connected to the input of the second conversion unit of the time interval, and its output is connected to the memory unit, the second input of which is connected to the second threshold output of the phase-sensitive unit, the output of the memory unit and the output of the first conversion unit time interval are connected to the inputs of the summing unit and comparing the time with the on time of the backup power switch, the output of the summing and comparing unit is connected to the input a single body with the control unit switches of the output.

In the event of a power loss, the device detects an increase in the angle 6 between the EMF vectors of the motors and the mains voltage and determines the moment of common-mode supply of the backup power, taking into account the time of switching on the backup power switch. Due to the fact that the device takes into account the initial angle of the engine load and the degree of dependence of the resistance moment on the rotation frequency, it has a fairly high accuracy of the common-mode backup power supply. The phase in-phase feed in the device is determined based on the measurement of time intervals

changes in the dog angle of the first predetermined value (5i to the second 6d and from the first d to the third dz. Due to the correction available in the device, it provides the required accuracy in the angle of switching on the backup power even with sharp changes in the slew rate of angle b occurring in the interval from the moment the angle reaches the value di before the angle reaches the value 5 ° After completing the measurement of time intervals, that is, after the angle reaches the value 5 °, the operation of the device is based on the assumption that a further change Indeed, in most cases of power supply disturbances, sharp changes in the slew rate of angle d can occur before the angle reaches dz- Such changes in the speed of angle 6 can occur when short circuits are disconnected on the supply lines, when non-responsive motors are turned off and other

However, in some cases, such changes in the velocity of angle 5 can occur after the angle exceeds the z value. This will lead to a large error in the device and the supply of backup power at a large angle d or even in antiphase with a residual voltage on the motors. Such switching on is dangerous for motors due to the inadmissible values of currents and mechanical torques arising in them. In addition, self-starting of engines in most cases will be unsuccessful due to the occurrence of braking moments in the initial period of self-starting. The indicated errors in the operation of the device, as a rule, will arise upon shutdown of close short circuits or non-responsive motors, accompanied by a significant change in the speed of angle 5.

It is known that the backup power supply can be carried out not only strictly in phase, but also when the switching angle deviates from 5Cin in a certain acceptable range, limited by the values of the angle 5iAon and 52Dop (51dop 5Sin, 32dop 5sin). The values of 3-1dop and 52dop are determined on the basis of preliminary calculations or experimentally from the conditions of admissibility of currents and moments of motors and the success of their self-starting. By using this range, out-of-phase switching can be prevented due to a device error by introducing an angle lock. It is based on measurement

the current value of the angle d at the moment of operation of the summing unit and comparing the time with the turn-on time of the backup power switch. If the measured value of the angle is greater than the permissible value of 5iAon (5- | additional 51dop) and less than the permissible value

52dop (Idop 52dop), THEN THE SIGNAL FROM THE BLOCK The summation is not blocked and enters the output organ, which provides switching to the backup power. If the summation and time comparison unit is activated until the angle reaches 5iAOn, which indicates an unacceptable error in determining the moment of switching the backup power in phase, the signal from the summation block is blocked until the angle reaches 5ifl0n and only after the angle exceeds this value will the signal arrive to trigger the output organ. Thus, the signal will be blocked for some time, due to which the backup power will be turned on at an acceptable value for ironing, (

The values of (51Dop and phdop are determined by decreasing the values of 5iAOn and (Zadop by the value of changing the angle q during the time the backup power switch is turned on, on, at the maximum possible rate of change of angle

01dop 5n + | (tUoti-LwO dk + l f 2 () () | h 2

KZ where a is the maximum possible

friction, depending on the maximum load factor of the K3 engine and on the nominal value of the mechanical time constant of the unit Ta,

11dop - the time from the start of the engine run-down until the angle reaches the value

.O1dop

Similarly, based on the desired 52Dop value, the b2dop value is determined.

The purpose of the invention is to improve operational reliability by reducing error and preventing out-of-phase back-up power.

This goal is achieved in that in a high-speed device for automatically switching on the backup power supply of consumers with motor load, including a phase-sensitive unit with two inputs for connecting to the consumer section with motor load and to a backup power source with three

threshold outputs, the first and second of which are connected to two inputs of the first time interval measurement unit with a time interval conversion output unit, and the first and third to two inputs of the second time interval measurement unit, the output of which is connected to the input of the second time conversion unit interval, and its output is connected

to the memory unit, the second input of which is connected to the second threshold output of the phase-sensitive unit, and the output of the memory unit and the output of the first time interval conversion unit are connected to the inputs of the summing and comparing unit with the time of switching on of the backup power supply switch, and also containing an output an organ with a control unit for the circuit breakers at the output, an inverter, a trigger, an AND gate and an AND logic element are additionally introduced in series, the output being a logical element nta And connected to the input of the output organ, the second input

The AND gate is connected to the output of the summing and comparing unit with the on time of the backup power switch, the third input of the AND gate is connected to the inverter output, the input of which is connected to the third threshold output of the phase-sensitive block, and the second trigger input and the second input of the logic element AND NOT connected to the first threshold output of the phase-sensitive block.

Figure 1 shows a functional diagram of a high-speed device for automatically turning on backup power consumers with motor

load; Fig. 2a is a diagram of the operation of device blocks in case of power loss and the absence of a device error; on figb is a diagram of the operation of the device blocks in case of premature operation

a unit for summing and comparing the time with the on time of the backup power switch. In Fig. 2, dashed lines show signals that occur if backup power fails at 5 s.

The device comprises a phase-sensitive unit 1 with threshold outputs, two time interval measurement units 2 and 3, two time interval conversion units 4 and 5, a memory unit, a time and time comparing unit 7. by changing the switch of the backup power source, the output organ 8, the switch control unit 9, the phase-sensitive block 1 has inputs 10 and 11 and three threshold outputs 12, 13, 14. The device also contains an inverter 15, a trigger 16, an AND-NOT logic element 17 and the logical element And 18.

The inputs of the first time interval measurement unit 2 with the first output time interval conversion unit 4 are connected to the first 12 and second 14 threshold outputs of the phase-sensitive block 1. The inputs of the second time interval measurement unit 3 with the second time interval conversion unit 5 are connected to the threshold the outputs 12 and 13 of the phase-sensitive unit 1. The output of the first time interval conversion unit 4 is connected to the input of the summing unit 7 and comparing the time with the switch on time reserve a power source, the output of which is connected to the input of the AND gate 18, while the second input of block 7 is connected to the output of memory block 6, the first input of which is connected to the threshold output 14 of the phase-sensitive block 1, and the second to the output of the time interval conversion block 5 . The first threshold output 12 of the phase-sensitive unit 1 is also connected to the input of the AND gate 17 and the input of the trigger 16, the second input of which is connected to the second input of the logic gate And 18 and connected to the output of the inverter 15, the input of which is connected to the threshold output 13. The trigger output 16 is connected to the second input of the AND-NOT 17 logic element, the output of which is connected to the third input of the AND 18 gate. The output of the And 18 element is connected to the input of the output organ 8 with the output control unit 9.

The voltage of the consumer section with a motor load is connected to the first input 10 of the phase-sensitive unit 1, and the voltage of the backup power supply is connected to the second input 11. At the exit

12 of the phase-sensitive block 1, the signal appears when the angle 5 5 between the vectors of the applied voltages reaches the first preset value 5i, and at the outputs

13 and 14, respectively, of the second 62 and third 5h. The time interval measuring unit 2 measures the time the angle 5 changes from the first predetermined value d to the third 5h. Block 3 measures the time the angle changes from the first (5i to the second setpoint 5z. To increase the accuracy of operation, integrators on operational amplifiers that convert time intervals are used as blocks 2 and 3)

to proportional voltages. The conversion coefficients of blocks 4 and 5 depend on the selected values of di, 62, 5h and the angle of common-mode supply of reserve power

Dam - The memory unit 6 remembers the value of the output voltage of the unit 5 at the moment the angle reaches the third predetermined value 3c. Due to this, the magnitude of the indicated voltage of block 5 is

0 as a function of the angle of the load of the motors and the degree of dependence of the moments of resistance of their mechanisms on the rotation frequency and is used as the correction voltage. In block 7 is produced

5, summing the output voltages of blocks 4 and 6 and comparing the resulting voltage with the set voltage proportional to the on time of the backup power switch. When the voltage exceeds the setting of the resulting voltage, a signal appears at the output of block 7.

Inverter 15, trigger 16, logical element AND-NOT.17 and logical element AND 18

5 form an angle locking organ. In the normal mode, 6 5i, therefore, the outputs 12,13 and 14 will have a low signal level, and the output of the trigger 16 and the output of the AND-NOT 17 logic element will have a high signal level. In this case, the output organ does not work, because the signal at the output of the summing unit 7 is absent and will be formed only after successive passage through an angle d of three given

5 values 5i, 62, 5z.

With a loss of power to the motors, the angle d increases and the setpoints 61.62 and bz pass successively. The output voltage of block 4 after the angle reaches the third preset setpoint ds decreases linearly so that when the angle of the in-phase supply of the backup power supply (5Cyn, it should become zero (at b = 0 and the moment of resistance of the mechanism independent of the rotation frequency). When the angle reaches 5 °, a correction voltage proportional to the value of the load angle is introduced into block 7 from block 6

Q days, and taking into account the dependence of the resistance moment of the mechanism on the rotation frequency, and the resulting voltage in block 7 when the angle reaches dst is equal to zero. When the voltage exceeds the set voltage of the resulting voltage in block 7, a high-level signal appears at its output, which is fed to one of the inputs of the logic element And 18. Whether this signal arrives at the input of output organ 8 depends on the current value of the angle d , i.e. from

5

the presence of blocking signals at the other two inputs of the element And 18.

In case of power loss and q 5i, a high level signal appears at output 12, trigger 16 goes into information storage mode and does not change its state (high level of output at output), and an AND-NOT 17 logic element appears at the output low level signal, which will prohibit the passage of the high level signal of block 7 (in case of its erroneous appearance) to the output organ 8.

With a further increase in the angle and its excess of qg, a high level signal appears at output 13, a trigger 16 fires, a low level signal appears at its output, and therefore a high level enable signal appears again at the output of the NAND gate 17 . At the same time, a low-level signal is generated at the output of the inverter 15, which in this case blocks the passage of a high-level signal from the output of the summing unit 7 to the output organ 8. Exceeding the angle d by 51 DOP again leads to the appearance of a low signal at the output 13, which ensures unlocking the passage of the output signal of block 7. In this case, the trigger 16 again enters the information storage mode, and a high signal level remains at the output of the AND-NOT 17 element. Blocking signals at the inputs of AND element 18 are absent and the operation of block 7 leads to the appearance of a high level signal at the output of AND element 18, the output organ 8 is triggered, and the backup power switch is in-phase switched on.

The correction device available in the device increases the accuracy of the common-mode backup power supply when changing the load angle of the motors and the speed of angle D. If, during a loss of power during a run-down of the motors, a sharp change in the speed of angle b occurs and even taking into account the correction, block 7 generates an output signal at a time Corresponding to common mode switching, the indicated blocking by angle prevents non-phase switching of the reserve power supply. The device has sufficient accuracy in most cases, but if, nevertheless, an error in the choice of a moment in time by block 7 occurs, then it will usually be leading, i.e. block 7 is triggered at 5. In this case, the signal from the output of block 7 will go to the input of the output organ of the locking circuit only when the angle reaches 3iAon and the backup power will be supplied to

engines with a valid angle d.

The occurrence of an unacceptable delay in the response time of unit 7 is unlikely. However, if for some reason it still occurred, then the malfunctioning of the output organ 8 and the non-phase supply of the backup power supply will be prevented by

the fact that at 5 Y2Dop at the output of the AND-NOT 17 element there will be a low signal level, and at d 5g + 5Syn - a low level at the output of the inverter 15.

Angle lock also allows

power backup at angles d 5i. Such an inclusion is very favorable, since corresponds to high-speed common-mode switching without violating the dynamic stability of the engines beyond

power loss time. Such a switch-on, as a rule, can only be realized with a fast-acting backup power switch.

Selection of angle settings

# 1, ($ 2 and 5z are made on the basis of the obtained values 5in0n and Y2Dop as follows:

thirty

5l Fdop - 5sin, 5l 5H

Max

& -det - 5iAon;

Aspen

& &.

The use of a high-speed device for automatically switching on the backup power supply of consumers with a motor load will make it possible to reliably provide a fast in-phase switching of the backup power supply in case of loss of the main one due to various reasons, including in cases of power loss, accompanied by a sharp change in speed angle d, for example, when disconnecting short circuits or non-responsive motors.

0 In most cases, the device will provide in-phase switching on of the backup power with a switching angle of 5 Sik, and only in some modes, with an unfavorable ratio of factors, switching on

5 will be significant when the angle d ,. within the allowable range of inclination angles. But the inclusion provided in the latter case is valid

for engines and more favorable than non-in-phase.

Claims (1)

SUMMARY OF THE INVENTION A high-speed device for automatically switching on a backup power supply of consumers with a motor load, including a phase-sensitive unit with two inputs for connecting to a consumer section with a motor load and a backup power source and with three threshold outputs, the first and second of which are connected to two inputs of the first a time domain measuring unit with an output time interval conversion unit, and the first and third to two inputs of the second time and the interval, the output of which is connected to the input of the second time interval conversion unit, and its output is connected ° to the memory unit, the second input of which is connected to the second threshold output of the phase-sensitive unit, the output of the memory unit and the output of the first time interval conversion unit the inputs of the summing unit and comparing the time with the turn-on time of the backup power supply circuit breaker, as well as containing an output organ with an output circuit-breaker control unit, characterized in that, in order to increase the reliability of operation by reducing the error and prevent non-phase connection of the backup power supply, the inverter, the trigger, the AND gate and the AND gate are connected in series, the output of the AND gate being connected to the input of the output organ, the input input of the AND gate is connected to the output of the summing and comparing unit with the on time of the backup power switch, the third input of the gate AND is connected to the inverter output, the input of which is connected to the third threshold output of the phase-sensitive block, and the second trigger input and the second input of the logical element И-Н Е are connected to the first threshold output of the phase-sensing block. Phi & 2 Editor Compiled by N. Grebchenko Tehred M. Morgenthal Corrector E. Papp S}