SU1435298A1 - Apparatus for providing power supply for electric precipitator - Google Patents

Abstract

The device relates to electrostatic separation of materials and rials, can be used to power gas cleaning electrostatic precipitators and improves the efficiency of cleaning of gums by increasing the average pre-breakdown voltage on the electrostatic precipitator. The device for powering the electrostatic filters contains a single-phase transformer 1, one end the primary winding 2 of which is connected to one phase of the mains through the current reactor 3 and the bi-directional thyristor switch 4, which is full-fledged on two counter-parallel l- ((L

Description

four

WITH

ate

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about the included thyristors 5 and b, and the winding 7 is toric with one end under: lnachen to the earth potential, OTHER through the protective reactor 8 to one ijiy input terminal of single-phase inaccessible; 9) Other input terminal Koj oporo is intended to be connected to an electric (. filter 10, and the output is connected to a high-voltage thyristor gate

one . The first additional bidirectional thyristor switch 12 is turned on, between the other end of the primary winding and 2 and the second phase of the mains supply, the third phase of which is connected to the junction point of the second 15 and third 1 6 bidirectional thyristor cells, the fourth bidirectional thyristor switch 21 is connected between the second phase the mains and the connection point of the other output of the second bidirectional thyristor switch 15 with the current reactor 3, and the fifth bidirectional thyristor switch 24 is connected between one phase of the mains supply and the connection point no other output of the third bidirectional thyristor switch 16 with the other end of the primary winding 2 of the single-phase transformer 1, 2 or

one

The invention relates to the field of electrostatic methods of separating materials and can be used to power the electrostatic precipitators of gas cleaning and thermal power engineering of the non-ferrous and ferrous metallurgy, chemical industry, building materials industry, automotive diesel and other sectors of the national economy.

The aim of the invention is to increase the gas cleaning efficiency by increasing the average pre-breakdown voltage,

Figo shows a block diagram of the device for powering the electrostatic precipitators in Fig. 2, a diagram of the operation of the thyristor switches of the device, combined with the voltage diagram.

The device for powering the electrostatic precipitators contains a single-phase transformer 1, one end of the primary winding 2 of which is connected in one phase of the mains supply through the current reactor 3 and a bi-directional thyristor switch 4, made on two counter-parallel connected thyristors (t) 5 and 6, and the secondary winding 7 is connected at one end to the ground potential, the other through a protective winding, reactor 8 to one input terminal of a single-phase uncontrolled bridge rectifier 9. Another input terminal of the rectifier 9 is connected to the electrostatic precipitator 10, and output - to high-voltage thyristor valve 11.

The first additional bidirectional thyristor key (DCTK) 12, made on two opposite-parallel connected 13 and 14, is connected between the other end of the primary winding 2 and the second phase of the supply network, the third phase of which is connected to the connection point of the second 15 and third 16 DCTK, respectively

each on two counter-parallel

included T 17 and 18, 19 and 20, the fourth DCTK 21, executed on two oppositely connected T 22 and 23, is connected between the second phase of the supply network and the junction point of the other terminal of the second DTTU 15 with the current one: reactor 3, and fifth DCTK 24, made on two T 25 and 26 parallel-connected in parallel, is connected between one phase of the mains supply and

junction point of another pin

the third DDTK 16 with the other end of the primary winding 2 single-phase transformer 1.

The device works as follows.

Let at the moment of time (figure 2)

t,, t, t}, tij, tg, tg, t 8 and ty

The primary winding 2 of a single-phase transformer 1 is connected to two of the three phases of the supply network by switching on thyristor pairs, respectively: T5 and T19, T5 and T14, T14 and T17, T 17 and T25, T23 and 125, T19 and T23, T5 and T19, T5 and , T14 and T17, as a result of which a positive polarity voltage is generated on the electrostatic precipitator (the switching on of the high voltage thyristor valve 11 is synchronized with the switching on of each of the thyristor pairs),

 Turning on the thyristors is provided by applying control pulses to the control transitions and applying to the thyristors the mains voltage of the same polarity that coincides with the direction of conductance of the thyristors.

Turn off pairs (figure 2) T5 and TI9, T and Tl 4, T14 and T17, TI7 and T25, T23 and T25, T19 and T23, T5 and T19, T5 and T14, T 4 and T17 respectively in MO, - cops time s 4 "7 8) is provided by

Switching off Tb and T20, Tb and T13, TI3 and, T18 and T26, T22 and T2b, T20 pairs

and T22 at times t,

12

 one

c, 4

-

it is also ensured by the fact that at the indicated time points the polarity of the voltage applied to the thyristors changes sign to the opposite, and the current flowing through the thyristor becomes zero,

The presence in the circuit of inductive signals — the primary winding 2 of a single-phase transformer 1 and a current-limiting reactor 3 — leads to the fact that the thyristors are turned off at time t, + (3 + 4) el.grad. Therefore, points in time t; switch on thyristor pairs. select from

20 ratios t, + 4 el. hail,,

at the same time, the corresponding adjustment angles oi are less than 60 eh grades.

The specified orpai-giceny is necessary to eliminate the possibility that at the indicated times of a 25-phase short-circuit voltage occurrence of the voltage applied to

thyristors, changes sign to anti-. For example, at the instant of time the reverse, and the current flowing through the thyristor disconnects the primary winding, becomes zero, 2 single-phase transformer 1 and from, for example, at time t, 30 phases B and C by turning off the pair T 4 and T17.

If the angle of adjustment is 60 el. ,those. t, o t, then at the moment of time t, o the primary winding 2 of the single-phase transformer 1 is connected to the phases A and B by switching on the pairs Tb and T20, and the control transitions T 5 and 19 are given control pulses

Since at this point in time the voltage is rp. phase A is more voltage Ug phase B (bd eg), linear voltage AB is applied to T 5 and 19 g

the polarity that coincides with the direction — it proceeds at that moment-time

their conductivity, and they include — when T14 and 7 are still in the inclusivity (Fig. 2). Thus, the primary condition. Since the potential

the winding 2 of the transformer 1 has a Q-phase B greater than the potential of phase A and after connected to phases A and B of FIG. 1,

Starting from time point tj, the polarity of the mains voltage applied to T 5 and 19 changes its sign to 45. The opposite, the current flowing through the thyristors becomes equal to the phase potential of C, Tbi 20, 14 and 17 are in the conducting state to phase A and B, B and C are short-circuited.

Thus, with an increase in the average pre-breakdown voltage level of each of the polarities on the electrostatic precipitator, the efficiency of cleaning the dust-gas flow is increased,

Liu, and they turn off.

(ABOUT

50

Similarly, at times t

"Chg S 135 M5" 5 the primary winding 2 of a single-phase transformer 1 is connected to two of the three phases of the mains supply by turning on the pairs Tb and T20, Tb and T13, and T18, 55 T18 and T2b, T22 and T2b, T20, and T22, respectively. as a result, a negative polarity voltage is formed on the electrostatic precipitator.

14352984

Turn off pairs of TB and T20, TI3 and, T18 and T26, T22 and

and T22 at times t,

12

 one

c, 4

-

it is also ensured that at the indicated times the polarity of the voltage applied to the thyristors changes sign to the opposite, and the current flowing through the thyristor becomes zero,

The presence in the circuit of inductive signals - the primary winding 2 of a single-phase transformer 1 and a current-limiting reactor 3 - leads to the fact that the thyristors are turned off at time t, + (3 + 4) el.grad. Therefore, points in time t; switch on thyristor pairs. select from

ratios t, + 4 el. hail,,

at the same time, the corresponding adjustment angles oi are less than 60 eh grades.

The specified orpai-gicheniya is necessary to eliminate the possibility of a Q-phase B arising greater than the potential of phase A and by. 45

50

The 55 phases of phase C, TBi20, 14 and 17 are conductive to phase A and B, B and C are short-circuited.

Thus, with an increase in the average pre-breakdown voltage level of each of the polarities on the electrostatic precipitator, the efficiency of cleaning the dust-gas flow is increased,

The duration of each of the polarities of the voltage is chosen in each particular case from the condition of achieving the maximum degree of purification of the pypegase flow.

Claims (1)

Invention Formula . A device for powering an electrical power supply containing a single-phase transformer, a high-voltage thyristor h4n between the second conclusion of the primary Editor OvGolovach . yg.g Compiler BeDolotin Tehred M. Khodanich. Proof; MoVasilyeva Order 5583/7  525 VPIIPI USSR State Committee for inventions and discoveries 1130355 Moscow, Zh-355 Raushsk nab., 4/5. transformer Subscription