JPH04300662A - Pulse power supply apparatus for electric precipitator - Google Patents

Abstract

PURPOSE:To provide a pulse power supply apparatus for an electric precipitator capable of changing over a charge mode without once stopping charging. CONSTITUTION:A pulse power supply apparatus for an electric precipitator has a condenser 26 receiving the application of DC high voltage from a DC reactor 24 at one terminal thereof, a rotary spark gap 27 inserted between one terminal of the condenser 26 and an electric precipitator 29 and instantaneously discharging the charge of the condenser 26, a breaker 40 connected to the rotary spark gap 27 in parallel and a charge mode change-over means operating the rotary spark gap 27 at the time of the change-over of DC high voltage to pulse high voltage to open the breaker and closing the breaker 40 at the time of the change-over of pulse high voltage to DC high voltage to stop the rotary spark gap 27.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse power supply device for an electrostatic precipitator, and more particularly to a charging mode switching circuit.

0002

2. Description of the Related Art A pulse power supply device for an electrostatic precipitator is generally constructed to be able to selectively supply a DC high voltage and a pulsed high voltage to the electrostatic precipitator. FIG. 3 is a circuit diagram of a conventional pulse power supply device for an electrostatic precipitator.

In FIG. 3, the voltage of an AC power supply AC is adjusted by a thyristor 1, passes through a high voltage transformer 2, a rectifier 3, and a DC reactor 4, and then is switched to charging mode by charging mode changeover switches 5 and 8 as follows. It is supplied to an electrostatic precipitator (EP) 9 as a corresponding high voltage.

(1) DC high voltage supply mode control device 13
After controlling the gate voltage of the thyristor 1 to turn off the thyristor 1, the charging mode changeover switch 5,
8 to the a side, and then the thyristor 1 is turned on again to supply a DC high voltage to the electrostatic precipitator 9.

(2) Pulse high voltage supply mode control device 1
3 turns off the thyristor 1, switches the charging mode changeover switches 5 and 8 to the b side, then turns on the thyristor 1 again to charge the pulse capacitor 6, and the rotary spark gap 7 instantly turns off the pulse capacitor 6. By discharging the voltage, a pulsed high voltage is generated and supplied to the electrostatic precipitator 9.

FIG. 4 shows the thyristor 1 when switching the charging mode.
, shows the operation of the charging mode changeover switches 5 and 8 and the rotary spark gap 7, and the charging voltage waveform to the electrostatic precipitator 9. During operation of the pulse power supply device, the charging current of the electrostatic precipitator 9 is detected by the current detector 10, the voltage of the pulse capacitor 6 is detected by the voltage detector 11, and the charging voltage of the electrostatic precipitator 9 is detected by the voltage detector 12. and are fed back to the control device 13.

Here, the charging mode changeover switches 5 and 8 are installed on the upper part of the electrostatic precipitator 9, and the control device 13 is installed in the electrical room of the electrostatic precipitator 9. Therefore, as shown in the FP charging voltage waveform of FIG. 4, a charging stop state occurs when switching the charging mode. This charging stop state lasts for several minutes when the charging mode changeover switches 5 and 8 are manual, and for several seconds when the charging mode changeover switches 5 and 8 are electric.

[0008]

[Problems to be Solved by the Invention] As mentioned above, in the conventional pulse power supply device for an electrostatic precipitator, when switching the charging mode while the electrostatic precipitator is in operation, it is necessary to temporarily stop charging. This causes a decline in the performance of the dust collector.

[0009] Furthermore, when switching the charging mode, it is necessary to temporarily stop charging, which places a heavy burden on the operator, especially when the charging mode changeover switch is a manual type. Even in this case, complex operations are required.

Furthermore, since such manual operation is required to switch the charging mode, the pulse power supply device cannot be installed in the last chamber of the electrostatic precipitator, and this makes it difficult to optimize the performance of the electrostatic precipitator. It is a constraint on

The present invention has been made in view of these conventional problems, and an object of the present invention is to provide a pulse power supply device for an electrostatic precipitator that can switch the charging mode without temporarily stopping charging. .

0012

[Means for Solving the Problems] The present invention eliminates the charging mode changeover switch conventionally used in high voltage circuits, connects a circuit breaker in parallel with the rotary spark gap in its place, and connects the circuit breaker to the rotary spark gap. By timing and controlling the operation and stop of the gap, the charging mode can be switched without stopping the charge supply to the electrostatic precipitator.

That is, the pulse power supply device for an electrostatic precipitator of the present invention is inserted between a capacitor to which a high DC voltage is applied, and one end of the capacitor and the electrostatic precipitator, and is inserted between one end of the capacitor and the electrostatic precipitator. A rotary spark gap for instantaneous discharge, a circuit breaker connected in parallel with this rotary spark gap, and a circuit breaker connected in parallel with the rotary spark gap. The present invention is characterized by comprising charging mode switching means that opens the circuit breaker and stops the rotary spark gap after closing the circuit breaker when switching from pulsed high voltage to DC high voltage.

[0014]

[Operation] When the circuit breaker is closed and a high DC voltage is applied to the electrostatic precipitator, when the rotary spark gap is operated and the circuit breaker is opened, the high voltage is supplied to the electrostatic precipitator. automatically switches to pulsed high voltage. The circuit breaker is opened by, for example, instantaneously pulling up the contacts using an electromagnetic coil and extinguishing the arc with a gas such as air.

On the other hand, when the circuit breaker is opened and pulsed high voltage is being supplied to the electrostatic precipitator, when the circuit breaker is closed, the high voltage supplied to the electrostatic precipitator becomes a DC high voltage at this point. Automatically switches to voltage. Therefore, the rotary spark gap that is no longer required to operate after that is stopped. Closing of the circuit breaker is performed, for example, by de-energizing the electromagnetic coil and automatically bringing the contacts into contact by gravity.

[0016]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram of a pulse power supply device for an electrostatic precipitator according to an embodiment of the present invention, and FIG. 2 is an operating waveform diagram thereof.

In FIG. 1, the primary side of a high voltage transformer 22 is connected to an alternating current power source AC via a thyristor 21. The input side of a rectifier 23 is connected to the secondary side of the high voltage transformer 22. One end of a DC reactor 24 is connected to one end of the output side of the rectifier 23.
A pulse capacitor 26 is connected between the other end and the other end (ground) of the rectifier 23 . One end of a rotary spark gap 27 is connected to one end of the pulse capacitor 26, and an electrostatic precipitator (EP) 29, which is a load, is connected between the other end of the rotary spark gap 27 and ground.

An extra high voltage circuit breaker 40 is connected in parallel with the rotary spark gap 27. This special high voltage circuit breaker 40 includes an electromagnetic coil 41, an insulator 42
, a special high voltage circuit opening/closing contact section 43, a tank 44 for arc extinguishing air, etc., an AC power source 45 for the electromagnetic coil, and a charging mode changeover switch 46. It is assumed that the tank 44 is replenished with air or the like from, for example, a plant air system.

Further, a current detector 30 is inserted between the thyristor 21 and the primary side of the high voltage transformer 22, and the rectifier 23
A voltage detector 31 is installed on the output side of the electric precipitator 29 and on the input side of the electric precipitator 29.
32 are connected to each other. These detectors 30~
The detection result of 32 is fed back to the control device 33. The control device 33 controls the thyristor 21 based on these detection results.

Next, the operation of this embodiment will be explained with reference to FIG. The voltage of the AC power supply AC is adjusted by a thyristor 21, passes through a high voltage transformer 22, a rectifier 23, and a DC reactor 24, and then is supplied to an electrostatic precipitator 29 as a high voltage according to the charging mode as described below.

(1) DC high voltage supply mode In this mode, the extra high voltage circuit breaker 40 is closed. Therefore, the DC high voltage from the DC reactor 24 is transferred to the circuit breaker 40.
It is supplied to the electrostatic precipitator 29 through.

In this mode, a part of the DC high voltage from the DC reactor 24 is transferred to the pulse capacitor 26.
The voltage supplied to the electrostatic precipitator 29 is thereby smoothed. This works as a suppressing effect on the occurrence of reverse ionization and spark discharge, and can be considered as a secondary effect of the present invention.

(2) Pulse high voltage supply mode In this mode, the extra high voltage circuit breaker 40 is open. Therefore, the pulse capacitor 26 is charged by the DC high voltage from the DC reactor 24, and the charge in the pulse capacitor 26 is instantly discharged by the rotary spark gap 27. This generates a pulsed high voltage, and this pulsed high voltage is supplied to the electrostatic precipitator 29.

During operation of this pulse power supply device, the charging current of the electrostatic precipitator 29 is detected by the current detector 30, the voltage of the pulse capacitor 26 is detected by the voltage detector 31, and the charging voltage of the electrostatic precipitator 29 is detected by the voltage detector 31. The voltage detectors 32 detect the respective voltages, and the detection results are fed back to the control device 33. From this, the control device 33 controls the thyristor 21 so that these detection results become predetermined values.

FIG. 2 shows the thyristor 2 when switching the charging mode.
1. The operation of the extra high voltage circuit breaker 40 and the rotary spark gap 27, and the charging voltage waveform to the electric precipitator 29 are shown. As shown in FIG. 2, in the present invention, when switching the charging mode to the electrostatic precipitator 29 from the DC high voltage supply mode to the pulsed high voltage supply mode, after operating the rotary spark gap 27, Circuit breaker 40
open the circuit. When opening the circuit breaker 40, the contact portion 43 is instantly pulled up by the electromagnetic coil 41.
Gas such as air is supplied from the tank 44 to the contact portion 43 to extinguish the arc.

On the other hand, when switching the charging mode to the electric precipitator 29 from the pulse high voltage supply mode to the DC high voltage supply mode, the rotary spark gap 27 is stopped after the circuit breaker 40 is closed. When closing the circuit breaker 40, turn off the charging mode selector switch 46,
When the electromagnetic coil 41 is de-energized, the contact portion 43 automatically lowers due to gravity and closes.

When these charging modes are switched, the thyristor 21 remains on, and as shown in the EP charging voltage waveform in FIG. 2, a charging stop state does not occur even when the charging modes are switched. This solves the conventional problem of a charging stop state occurring when switching the charging mode.

[0028]

As explained above, according to the present invention, charging does not stop even if the charging mode is switched during operation of the electrostatic precipitator, so that the following effects can be obtained. (1) Deterioration in performance of the electrostatic precipitator due to temporary suspension of charging can be prevented.

(2) Since there is no need to temporarily stop charging when switching the charging mode, the operation is extremely simple and the burden on the operator is greatly reduced, regardless of whether the changeover switch is manual or electric. Ru. (3) There are no restrictions on the installation conditions of the pulse power supply, allowing for optimal planning of electrostatic precipitator performance. (4) The charging mode selector switch only needs to control the circuit breaker and does not need to directly control the high voltage circuit.
The switch can be made smaller.

(5) When charging with DC high voltage, the voltage supplied to the electrostatic precipitator is supplied to the pulse capacitor through the circuit breaker and smoothed, so it is possible to suppress the occurrence of reverse ionization and spark discharge. .

[Brief explanation of drawings]

[Fig. 1] Circuit diagram of a pulse power supply device for an electrostatic precipitator according to an embodiment of the present invention.

[Figure 2] Diagram showing the operating waveforms of the circuit in Figure 1

[Figure 3]
Circuit diagram of conventional pulse power supply device for electrostatic precipitator

[Figure 4]
4 is a diagram showing operating waveforms of the circuit in FIG. 3. FIG.

[Explanation of symbols]

21...thyristor
22... High voltage transformer 23... Rectifier
24...DC reactor 26...Pulse capacitor
27...Rotary spark gap 29...Electric precipitator
30...Current detector 31...Voltage detector
32...Voltage detector 33...Control device
40... Extra high voltage circuit breaker 41... Electromagnetic coil
42...Insulator 43...Special high voltage circuit switching contact
44... Tank 45... Power supply for electromagnetic coil
46...Charging mode selection switch

Claims (1)

[Claims] 1. A pulse power supply device that selectively applies a DC high voltage and a pulsed high voltage to an electrostatic precipitator, comprising: a capacitor to which a DC high voltage is applied; A rotary spark gap inserted between the dust collector and the capacitor to instantly discharge the charge in the capacitor, a circuit breaker connected in parallel with the rotary spark gap, and a switch from DC high voltage to pulsed high voltage. At this time, after operating the rotary spark gap, the circuit breaker is opened, and when switching from pulsed high voltage to DC high voltage, after closing the circuit breaker, the charging mode is switched to stop the rotary spark gap. 1. A pulse power supply device for an electrostatic precipitator, comprising: means.