SU1743014A1 - Induction plant - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to increase the reliability of the installation by adjusting the over-current harmonics of the supply voltage from overloading. The presence of sensors of electrical parameter 4 and 5, voltage switch 6, block for calculating overload 7, threshold organ 9, block for switching stages of a capacitor battery 10 in combination with simulator 13 and block for calculating simulator organ overload reduce the network and element overload by high harmonics. 6 Il.

Description

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The invention relates to electrical engineering, in particular, to power supply devices of induction installations, and can be used in power supply systems and power supplies of electrical technology installations.

The aim of the invention is to increase the reliability of operation of the elements of the induction installation by detuning the higher harmonics of the supply voltage while overloading them with currents while maintaining a predetermined voltage level of the supply network while maintaining the specified voltage level on the induction system.

FIG. 1 is a schematic diagram of the installation; Fig 2 is a circuit of a voltage switch; in fig. 3 is a diagram of connecting a threshold organ to an overload calculation unit; in fig. 4 is a block for switching the steps of a capacitor bank; in fig. 5 is a circuit diagram of a battery control unit of compensating variable power capacitors; in fig. 6 - dependences of the components of complex conductivity on frequency.

The installation consists of a parallel battery of induction system 1, battery 2 of compensating capacitors of adjustable power, series reactive, for example capacitive, element 3 of adjustable power, electrical sensors 4 and 5, voltage switch 6, block 7 for calculating overload, filter 8 high harmonics, the threshold element 9, the block 10 switching steps of the capacitor battery, the battery control unit 11 of the compensating capacitors, the control unit 12 of the sequential reactive element regulating my power simulating body 13 and a unit 14 for calculating modeling overload body.

A battery of 2 compensating capacitors of adjustable power consists of groups of capacitors switched by contact or contactless equipment. Serial reactive element 3 of regulated power can be made similarly to unit 2 or, in the case of an inductive nature, in the form of throttles with adjustment by taps.

Sensors 4 and 5 are current transformers, voltages, shunts, or a combination of these, depending on the developed monitored parameter (voltage, current, active power, etc.).

The voltage switch 6 (Fig. 2) contains a pulse generator 15, to the input of which a supply voltage is applied, and

the output is connected to the trigger input 16, the first output of which is connected to the relay 17, and the second output to the relay 18. The outputs of the relay 17 and 18 are connected to ground.

As block 7 for calculating overload and block 14 for calculating the overload of a simulator (Fig. 1), well-known devices can be used to calculate the non-sinusoidal voltage and / or current, for example, an instrument for monitoring the non-sinusoidal voltage waveform.

As a filter 8 harmonics (Fig. 1) used an active filter at a frequency of 100-2000 Hz.

A comparator was used as the threshold organ 9 (Fig. 3), the first input of which is connected to the analog output of the overload calculation unit 7, and the second input to the output of the high harmonic filter 8. The first and second outputs of the threshold organ 9 are connected to the first inputs of the control units 11 and 12, respectively.

Block 10 (Fig. 4) contains a relay 19, the first output of which is connected to the third output of the threshold organ 9, the second output of relay 19 is connected to ground, an analog-to-digital converter 20, the input of which through the closing contact 21 of relay 19 is connected to the output of computing unit 14 the simulator overload, and the output to the input of the storage device 22, the output of which is connected to the input of the digital-to-analog converter 23, the output of which is connected to the first input of the threshold organ 24, to the second input of the threshold organ 24 is connected to the output of the calculation unit 14 overload simulator, the output of the threshold body 24 is connected to the input of timer 25, the output of which is connected to the first input of the binary counter 26, three outputs of which are connected to the first three inputs of the decoder 27, the first inverse output of the decoder 27 is connected to the input of the relay 28, the second inverse output of the decoder 27 - to relay input

29, the third inverse output to the input of the relay

30, the fourth inverse output to the input of the relay 31. The fifth, sixth and seventh inverse outputs of the decoder 27 are connected to the inputs of the ZI-HE element 32, the inverse output of which is connected to the fourth input of the decoder 27 and the input of the element 33, the inverse output of which is connected to the input element 34, the inverse output of which is connected to the second input of the binary counter 26.

The battery control unit 11 of the adjustable power compensating capacitors contains a switch of 35 steps

voltage (Fig. 5), which is connected to one phase of the supply network (A), the first four outputs of which correspond to the first, second, third and fourth steps are connected to the input of the time relay 36, the closing contact 37 of the time relay 36 and the first closing contact 38 of relay 39, and both contacts are connected to the input of relay 39. These same four outputs are connected to the opening contact 40 of relay 31, the opening contact 41 of relay 30, the opening contact 43 of relay 28. Contact 40 is connected to the first closing contact 44 of time relay 45 and second make contact 46 relays 45 times. Contact 41 is connected to the first closing contact 47 of the time relay 48 and the second closing contact 49 of the time relay 48. The contact 42 is connected to the first closing contact 50 and the second closing contact 51 of the time relay 52. Terminal 43 is connected to the closing contact 53 of the time relay 54. Contact 44 is connected to the first output coil of the relay 48, contact 46 to the first output of the coil of the contactor 55. Contact 47 is connected to the first output of the coil of the relay 52, contact 49 to the first output of the coil of the contactor 56. Contact 50 is connected to the first output of the coil of the relay 54, contact 51 - with the first output of the coil of the contactor 57. Contact 53 is connected to the first output of the contactor 58. The second four outputs of the switch 35 voltage levels corresponding to the first, second, third and fourth stages are connected to the first terminals of the coils of the contactors 55-58, respectively, the second terminals of which are connected to the second closing contact 59 of the relay 39. The second terminals of the relay coils 36, 39, 48, 52 and 54 and the contact 59 are connected to the second phase of the supply network (B). The first terminal of the coil of the time relay 45 is connected to the output of the threshold organ 9, and the second is connected to ground.

The control unit 12 for controlling the successive reactive element 3 of adjustable power is made similar to block 11.

As a modeling organ 13 (Fig. 1), for example, a capacitor connected in parallel with the power supply device was used. The validity of using a capacitor is confirmed by studying the frequency characteristics of a series-parallel capacitive voltage converter. Thus, in FIG. Figure 6 shows the dependences of the components of the complex conductivity of the converter on the frequency in the range of changes in the parameters of capacitive elements. At the same time, curves 1-4 correspond to the following parameters of capacitive elements: 1-Ci curve 3.82 F; Ca 3.48 103 F; curve 2 - d 3.82 - F; C2 3.14-F; 3-Ci curve 3.82 -10 4F; C2

3.48 curve 4-Ci 3.82-F; C2 3.14 F, where Ci and C2 are the capacitors of the series and parallel capacitors. Parameters of active-inductive load (electromagnetic system

channel induction installation) the following: R 0.45 Ω, L 1,708-10 Gn. From the analysis of the curves of FIG. 6, it follows that at frequencies corresponding to harmonic numbers v 2, the amplitude-frequency characteristics are straight lines, and the phase frequency characteristics (phase response), starting with V-3, almost correspond to the phase response of the capacitive element, as confirms the legitimacy of using such an element in the modeling body 13. It should be noted that more complex circuits can be used as a modeling body, for example a series-parallel capacitive voltage divider

active-inductive load connected through a voltage transformer, etc.

The installation works as follows.

When the supply voltage is applied to the pulse generator 15, it generates pulses, in accordance with the sign of which the trigger 16 produces an alternate VC switching on the relay 17 and 18. The relay 17 connects the calculation block 7 with its contacts

overload and filter 8 harmonics to the sensor 4 signals, and the relay 18 - sensor 5 signals. Filtered from higher harmonics, the voltage is applied as the voltage of the Bush installation to the second input.

the threshold organ 9, the first input receives the voltage from the block 7 for calculating the overload proportional to the overload of the reactive elements. Simultaneously, the simulator overload calculation block 14

The body controls the overload of the modeling body 13 and provides a voltage proportional to the overload of this body to block 10.

In the normal operation of the power source, when the overload of the reactive elements is less than acceptable, the voltage at the first input of the threshold organ 9 is less than the voltage of the set point, the voltage at the output of the threshold organ 9 is zero,

and the control units 11 and 12 operate on a voltage level switch. When the voltage level is manually switched by the switch 35 (Fig. 5), for example, a relay 36 is triggered to the second level. After

actuation of this time delayed relay closes its contact 37, which ensures the operation of the relay 39, and triggered contact 38 puts the relay 39 on self-blocking. Contact 59 of relay 39 provides the operation of the coil of contactor 56.

In the overload mode of operation of the power source, when the overload of reactive elements exceeds the allowable voltage at the first input of threshold organ 9 is higher than the set voltage, the threshold organ triggers and supplies voltage to relay 45 of control unit 11 and 12 as well as to relay 19 of unit 10 .

Relay 45 is activated and with time delay closes its contact 44 and self-locking contact 46. Contact 44 turns on time relay 48, and contact 46 turns on contactor 55 coil. If the overload does not disappear, then contacts 47 and 49 of relay 48 close with time delay. Contact 47 turns on time relay 52, and contact 49 turns on contactor 56 coil. If the overload does not disappear, then contacts 50 and 51 of relay 52 close with a time delay. Contact 50 turns on time relay 54 and contact 51 turns on contactor 57 coil. If at this stage overload disappeared then The output at the output of the threshold organ 9 became equal to zero and the relay 45 turned off, having turned off its contacts 44, 47 and 50, de-energized the relays 48, 52 and 54; however, the coils of the contactors 55-57 are fed through closed, self-locking contacts 46, 49 and 51. The control unit 12 controls the sequential reactive element 3 of controlled power similarly.

Simultaneously with the inclusion of the relay 45, the relay 19 is triggered (Fig. 4) and produces a short-term connection of the block 14 for calculating the overload of the modeling body to block 10. A voltage proportional to the overload of the modeling body 13 at the moment of overloading the reactive elements of the source through the pulse-closing contact 21 of the relay 19 arrives at analog-to-digital converter 20, from where, in digital form, to storage device 22, where it is stored, and through digital-to-analog converter 23 in analog form goes to input of threshold organ and 24 as a voltage setpoint. The second input of the threshold organ 24 is supplied with voltage from the block 14 for calculating the overload of the modeling organ.

The overload of the simulator 13 is monitored and the obtained value is compared with the overload value,

which was at the time of triggering the threshold organ 9. If the level of higher harmonics in the mains voltage decreased, the overload of the simulator 13 into the voltage at the second input of the threshold organ 24, respectively, became lower than the set voltage. The threshold authority 24 is triggered and starts a timer 25 connected to the first input.

binary counter 26. From the outputs of binary counter 26, a code is taken and fed to the inputs of the decoder 27, where it is converted into a position code. At the first output of the decoder, a voltage appears and a relay 28 is triggered. It opens the contact 43 of the control units 11 and 12. Then the voltage appears at the second output of the decoder 27, the relay 29 is triggered. It opens the contact 42 of the control units 11 and 12. The lock is removed from pin 51, it turns off and removes power from the coil of contactor 57. The control unit turns off the third stage. Then the voltage appears at the third output of the decoder 27, the relay 30 is triggered, the contact 41 is opened, the lock is released from the contact 49, the coil of the contactor 56 is turned off, the second stage is turned off. The first stage is turned off in the same way, after which the block

11, the control proceeds to work from a voltage step switch 35, and the step set is performed manually.

Elements 32-34 serve to install the decoder 27 and the binary counter 26 in

initial position.

The use of the invention improves the reliability and service life of the power device elements. It is known that the overloading of capacitive elements by currents

higher harmonics reduces their reliability and service life. For example, a voltage rise of 10% reduces the service life of capacitors by a factor of 2.2, and at relative harmonic values of voltage Us 0.04;

U 0.03; Un Uia 0.02 The lifetime of the insulation is reduced by 53% with stable operation of the capacitors. The presence of higher harmonics leads to great damage to electrical equipment.

Claims (1)

Induction installation, comprising an induction system and an adjustable battery of compensating capacitors connected to it in parallel with a control unit, connected to a power source in series with a variable power reactive element with a control unit characterized in in order to increase reliability By adjusting the over-current harmonics from overloading, the supply voltage while maintaining a predetermined voltage level on the induction system, electrical sensors of a battery of compensating capacitors and a reactive element, a voltage switchboard, an overload calculation unit, a higher harmonic filter, a threshold organ, a block switching capacitor bank steps, a simulator and a block for calculating the overload of a simulator; the outputs of the electrical parameter sensors are connected to the inputs of the switch & / OKU 6 and to s / s 7 FIG 3 the voltage torus, the first output of which is connected through the block of calculation of the overload, and the second through the filter of higher harmonics is connected to the inputs of the threshold organ, two the outputs of which are connected to the first inputs of the control units of the battery of the compensating capacitors and the reactive element, and the third to the input of the switching unit of the steps of the capacitor battery, the control input of which is connected to the output of the modeling unit through the overload calculator and both outputs to the second inputs of the specified control units . 15 one Fig 2 35 TO 5IOKU Yu, I. 12 UCT TO BLOCK (H 23 24 5 2e // MSN and TO BLOCK ee one Zk ABOUT to 5 I J24 5 2e // SN 3JN L I | 3i 45 Unln HRLL 90 1 i