JPH0362468B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a power supply device for an electrostatic precipitator (hereinafter abbreviated as EP), which can selectively switch between pulse charge or DC charge by operating a high voltage switching device.
This relates to an EP power supply device.

[Conventional technology] As shown in Figure 6, the conventional EP power supply device is as follows.
A DC high voltage generator (its output is applied to a discharge electrode 49 and a dust collection electrode 50) is composed of a high voltage transformer 47 equipped with an AC primary side power control device 46 and a rectifier 48. Recently, a charging method called pulse charging has begun to be put into practical use in EP as a countermeasure against the deterioration of dust collection properties due to the properties of collected dust.

This pulse charging method is due to the extremely high electrical resistivity of the collected dust due to the repeated application of a pulsed high voltage with an extremely steep rise between the discharge electrode and the dust collection electrode of the EP. As a result of the abnormal discharge phenomenon (called reverse ionization) that occurs,
It significantly improves the reduced dust collection,
The basic power supply configuration is as shown in FIG. 4, in which a pulse high voltage generated from a pulse generating power source 40 and a DC high voltage generated from a DC high voltage power source 41 are capacitively coupled by a coupling capacitor 42, and the pulsed high voltage is converted to a DC high voltage. There are two types: a so-called two power supply combination type in which high voltage is superimposed and applied to the discharge electrode 43 of the EP, and a so-called direct connection type in which the output of the pulse generation power supply 44 as shown in FIG. 5 is directly connected to the discharge electrode 45 of the EP. There are several possible methods.

As mentioned above, the pulse charging method is said to be particularly effective as a countermeasure against reverse ionization, but this reverse ionization phenomenon becomes more pronounced as the electrical resistivity of the collected dust increases, and as a result, as shown in Figure 3. In DC charging using the conventional power supply device shown in FIG. 6, the higher the electrical resistivity of the collected dust, the lower the dust collection performance. On the other hand, in pulse charging, in general, the higher the electrical resistivity of the collected dust, the higher the rate of improvement in dust collection performance compared to DC charging, and conversely, the lower the rate of improvement, the lower the rate of improvement. In other words, it exhibits a characteristic that DC charging and dust collection performance are almost the same.

[Problem that the invention seeks to solve]

As is obvious, in the above-mentioned DC charging power supply device and pulse charging power supply device, the charging method is uniquely fixed. Therefore, in cases where the electrical resistivity of the collected dust varies greatly depending on the type of coal used, such as in EP for coal-fired boilers, if the electrical resistivity of the collected dust is low, due to the characteristics shown in Figure 3, the dust collection performance is almost negligible. Even though it is not effective, it ends up operating with pulse charging, which consumes extra power and wears out components. On the other hand, when a power supply device for DC charging is adopted, DC charging alone cannot deal with the drop in dust collection performance when the electrical resistivity of the collected dust increases due to changes in the type of coal used or other conditions.

In addition, if a pulse charging power supply device is used,
When the pulse generator fails, it is impossible to perform a quick backup process and continue operation, and the charging of that section is stopped.

An object of the present invention is to provide an EP power supply device that can solve the above-mentioned conventional problems.

[Means for solving problems]

The EP power supply device according to the present invention includes: (1) a rectifier controlled by an AC primary side power control device via a high voltage transformer, a first high voltage switching device connected to the output side of the rectifier, and two switching contacts. a pulse generator having a capacitive energy storage element and a fast switching device connected to one contact side of the first high voltage switching device having a
The output is interlocked with the first high voltage switching device,
Similarly, it is connected to one contact of a second high voltage switching device having two switching contacts, and the remaining contact of the first high voltage switching device and the remaining contact of the second high voltage switching device are electrically connected, It is composed of a voltage detection device and an electrode connected in parallel to the output side of the second high voltage switching device, and the first high voltage switching device and the second high voltage switching device are operated manually, by an external command, or by automatic control. , it is possible to select whether to connect the output of the rectifier to the discharge electrode directly or via the pulse generator.

Further, the EP power supply device according to the present invention includes: (2) a first rectifier controlled by a first AC primary side power control device via a first high voltage transformer; and a capacitive energy storage element connected to the output side of the first rectifier. and a pulse generator having a high-speed switching device, a waveform shaping resistor connected to its output side, a discharge electrode and a voltage detection device connected in parallel to its output side via a coupling capacitor and a high voltage switching device, a control circuit that is controlled by a voltage detection device and controls the first AC primary side power control device and also controls the high voltage switching device; A second rectifier controlled by a side power control device. That is, in the present invention, (1) By providing a high voltage switching device in the configuration of the pulse charging power supply device, the pulse generation section is separated and the output of the DC high voltage generator, which is one of the components, is connected to the EP discharge. By connecting directly to the electrode, it is possible to perform DC charging in addition to pulse charging.

(2) By using an automatic high voltage switching device, a failure of the pulse generator or any internal or external command is detected, and based on that, the high voltage switching device is activated and automatically selects pulse charging or DC charging. and was able to continue driving.

[Effect]

According to the present invention, the high voltage switching device included in the pulse charging power supply device can be operated manually or automatically based on internal or external commands, and either the pulse charging operation circuit or the DC charging operation circuit can be selected. and drive the vehicle.

〔Example〕

Hereinafter, the EP power supply device of the present invention will be explained with reference to the drawings. FIG. 1 shows an example of the application to the direct-coupled pulse charging power supply device described above in FIG. Ru. The output 12 of the rectifier 3 is connected to a common contact 17 of the high-voltage switching device 4, whose contact 19 is connected to the conductor 13 and also to the contact 1.
8 are respectively connected to the conducting wire 14, and serve as a DC charging side and a pulse charging side, respectively. Connected to the conductor 14 are a capacitive energy storage element 6 (such as a high-voltage capacitor, a high-voltage coaxial cable, etc., hereinafter referred to as a capacitor) of a pulse generator 25 and a high-speed switching device 7. Here, a spark gap or the like is mainly used as the high-speed switching device 7, but a hydrogen thyratron or a high-speed thyristor may also be used. The output of the high-speed switching device 7 is connected via a conductor 15 to a contact 20 of the second high-voltage switching device 5 . On the other hand, the conducting wire 13 is connected to a contact 21 of the high voltage switching device 5, and the common contact 22 thereof is connected to the discharge electrode 9 of the EP via a conducting wire 16. Further, the dust collecting electrode 10 is grounded.

The high voltage switching devices 4 and 5 are manually or electrically operated, for example, when pulse charging is selected, the high voltage switching device 4
The common contact 17 of the high voltage switching device 5 is connected to the contact 18 (contact 19), and the common contact 22 of the high voltage switching device 5 is connected to the contact 20
(contact point 21).

The AC primary side power control device 1 feeds back the charging voltage signal V from the voltage detection device 8 from the control circuit 11; inputs the output adjustment signal A resulting from the calculation, and controls the primary AC power of the high voltage transformer 2 based on the output adjustment signal A. and adjusts the output DC high voltage of the rectifier 3. When the above-mentioned high voltage switching devices 4 and 5 are operated manually or electrically by a command S from the control circuit 11 and select the pulse charging side, the output 12 of the rectifier 3 is as follows.
It is connected to the capacitor 6 through the common contact 17, the contact 18, and the conductor 14, and is connected to the capacitor 6 at a predetermined voltage (10~
100 ^kV ), and at a predetermined timing, the high-speed switching device 7 becomes conductive, and the charged charge suddenly connects the conductor 15, the contact 20, and the common contact 2.
2. A pulse charging operation is performed in which discharge is caused through the conducting wire 16 and a pulsed high voltage having an extremely fast rise is repeatedly applied between the discharge electrode 9 and the dust collecting electrode 10. Further, the high voltage switching devices 4 and 5 similarly
If DC charging side is selected, output 12 of rectifier 3
are common contact 17, contact 19, conductor 13, contact 2
1. It is connected to the discharge electrode 9 through the common contact 22 and the conductor 16 to perform DC charging operation.

The above-mentioned switching of the charging method can of course be performed by manual operation of the high voltage switching devices 4 and 5, but automatic switching as described below can also be performed.

(1) Automatic switching of charging method depending on the charging state It is generally known that when the above-mentioned reverse ionization phenomenon becomes severe, the average value of the charging voltage decreases from the normal value, but the charging voltage signal of the voltage detection device 8 V is input to the control device 11, the average value Va of the charging voltage is calculated, and this average value and the setting value V ₁ of the setting device 23 (V ₁ is the average value of the charging voltage 10 to
100 ^kv adjustment range), and for Va<V ₁ ,
It is determined that the back ionization has become intense, and only when the high voltage switching devices 4 and 5 have selected the DC charging side, a switching command S for the pulse charging side is sent and activated. Of course, this will not work if the pulse charging side has already been selected. Similarly, compared with the setting value V ₂ of the setting device 24 (V ₂ is an adjustment range of 10 to 100 ^kv as the average value of the charging voltage),
If Va > V ₂ , it is judged as a normal state in which no reverse ionization occurs, and only when the high voltage switching devices 4 and 5 have selected the pulse charging side, a switching command S to the DC charging side is sent and this is make it work. The above is an example of detecting the charged state and operating based on the detected state. However, other methods for detecting the charged state include detecting the current flowing through the EP,
There are various possible reasons such as depending on the value.

(2) Automatic switching in the event of failure of the pulse generator When a failure of the capacitor 6 or the high-speed switching device 7, which is a component of the pulse generator 25, is detected by a method not particularly limited in the present invention, for example, a failure signal of the high-speed switching device 7 is detected. F is input to the control device 11, and since it is impossible to continue the pulse charging operation, the high voltage switching devices 4 and 5
Sends a switching command S to the DC charging side to operate this.

In addition to the automatic switching described above, by inputting a switching command D to the control device 11 from the outside, the pulse charging side and the DC charging side can be selected in the same manner.

On the other hand, FIG. 2 shows another embodiment of the present invention which is adapted to the two-power supply combination type pulse charging power supply device described above in FIG. 4. Numbers 1 to 3 and number 6 in Figure 2
11 are the same as the components already described in FIG. A coupling capacitor 31 and a coupling capacitor 31 for the purpose of capacitively coupling the output DC high voltage of the conventional DC high voltage generator shown in FIG. It consists of a high voltage switching device 32 for disconnecting the pulse generating power source 36 of the circuit to the left of the capacitor 31.

In this embodiment, the above-mentioned switching between DC charging and pulse charging is performed by turning on the high voltage switching device 32 (pulse charging).
and OFF (direct current charging), and its operation is exactly the same as in the case of the direct connection type described above.

Note that the high voltage switching devices 4 and 5 in FIG. 1 and the high voltage switching device 32 in FIG. For example, a combination of an electric motor and a chain, an electromagnetic type, etc. are not particularly limited in the present invention. In addition, the high voltage switching devices 4, 5, and 32 must be operated when the voltage applied to each of them is temporarily set to 0 or lowered to a predetermined level, and switching commands are issued to the related high voltage power supplies. Needless to say, immediately before issuing the output voltage, a command for low output voltage or zero output is issued.

〔Effect of the invention〕

As described in detail above, according to the EP power supply device according to the present invention, one unit can arbitrarily select pulse charging operation and DC charging operation, and two charging chambers of the connected EP can be used.
The above two charging methods can be used automatically based on the charging state of the charging chamber, failure of the pulse generator in the power supply, or any external command. As an EP power supply, it can flexibly deal with fluctuations in conditions such as collected dust, and can also be used as a back-up in the event of a failure, increasing reliability. is played.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are examples of the present invention.
Figure 3 shows the dust collection performance based on the electrical resistivity of the collected dust, and Figures 4 to 6 show the direct connection type and the two power supply combination type, respectively. Figures 4 to 6 show the two power supply combination type and the direct connection type pulse charging, respectively. 1 is a schematic configuration diagram of a conventional power supply and a power supply for a conventional power supply. 1... AC primary side power control device, 2... High voltage transformer, 3... Rectifier, 4, 5, 32... High voltage switching device, 6... Capacitive energy storage element, 7... High speed switching device, 9...discharge electrode, 10...dust collection electrode, 25...pulse generator.

Claims (1)

[Claims] 1. A rectifier controlled by an AC primary side power control device via a high voltage transformer, a first high voltage switching device connected to its output side, and a first high voltage switching device having two switching contacts. a pulse generator having a capacitive energy storage element and a fast switching device connected to one contact side of the high-voltage switching device, the output of which is coupled to said first high-voltage switching device and also connects two switching contacts; the remaining contacts of the first high voltage switching device and the remaining contacts of the second high voltage switching device are electrically connected, and the output side of the second high voltage switching device The first high voltage switching device and the second high voltage switching device are operated manually or by an external command or automatic control, and the rectifier is connected to the discharge electrode in parallel. A power supply device for an electrostatic precipitator, characterized in that it is possible to select whether to connect the output directly or through the pulse generator. 2. The power supply device for an electrostatic precipitator according to claim 1, wherein the AC primary side power control device is controlled by a detected value of the voltage detection device. 3. The power supply device for an electrostatic precipitator according to claim 1, wherein the first high voltage switching device and the second high voltage switching device are automatically controlled based on the detected value of the voltage detection device. 4 a first rectifier controlled by a first AC primary side power control device via a first high-voltage transformer; a pulse generator having a capacitive energy storage element and a high-speed switching device connected to the output side thereof; a waveform shaping resistor connected to the output side; a discharge electrode and a voltage detection device connected in parallel to the output side via a coupling capacitor and a high voltage switching device;
a control circuit that controls an AC primary side power control device and also controls the high voltage switching device;
1. A power supply device for an electrostatic precipitator, comprising: a second rectifier controlled by an AC primary side power control device.