SU1699613A1 - Method for operating power pack of electrofilter - Google Patents

Abstract

The invention relates to methods for controlling power units of electrostatic precipitators equipped with a thyristor regulator in the primary winding of a step-up transformer, can be used to organize the power supply of electrostatic precipitators and allows an increase in the degree of gas purification. The control method of the electrostatic precipitator power unit is to optimize the valve control angle of the thyristor regulator by changing the accelerated lifting angle according to the condition: lifting. In the absence of secondary breakdowns, the accelerated lifting angle is increased, and in the event of secondary breakdown, it is reduced by fixed steps. In addition, the rate of increase of the control angle is optimized by the criterion of the maximum average voltage on the electrostatic precipitator. 1 hp ff, 1 ill. (Ls

Description

The invention relates to electrical engineering, in particular, to methods for controlling electrical quantities, and can be used in the field of electrical purification of industrial emissions from suspended particles, in particular for high-voltage recovery-rectifying installations for powering electric precipitators equipped with a thyristor regulator in the primary winding transformer.

The aim of the invention is to increase the degree of gas purification.

The drawing shows a block diagram of an apparatus for carrying out a control method on an electrostatic precipitator.

The block diagram contains a central processor (CPU) 1, a constant 2 and 3 operational memory (RAM), a timer 4 that performs the functions of an output device, an analog-to-digital converter (ADC) 5 that serves as an input device and is connected to the sensor 6 for example and an electrostatic precipitator current sensor 7, and an amplifying-rectifying unit containing a thyristor controller 9, a pulse shaping unit 10, a step-up transformer 11, a high-voltage rectifier 12. a synchronization unit 13, and a power supply unit 14.

A device for implementing the method works as follows.

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After start-up, processor 1 loads in timer 4 a number corresponding to the minimum steering angle. The voltage on the electrostatic precipitator increases until the beginning of the corona (about 24 kV). The processor 1, reading the readings of the ADC 5, obtains information about the voltage and current of the electrostatic precipitator 8.

In the absence of a short circuit in the electrostatic precipitator 8, the processor 1 decreases the number loaded into timer 4 and increases the angle F of adjustment by the power thyristors 9. The voltage on the electrostatic precipitator 8 increases smoothly.

During the mains voltage period, processor 1 repeatedly (for example, 32 times) polls voltage sensors 6 and current 7 of electrostatic precipitator 8 at regular intervals. If during a single survey it is established that the voltage on the electrostatic precipitator 8 has decreased to a certain value, for example 5 kV, a decision is made on the occurrence of spark breakdown. If the voltage on the electrostatic precipitator 8 is lower than 5 kV at the next interrogation of the A / D converter 5, a decision is made on the presence of an arc sample.

When a spark breakdown is detected, the control angle increases by the angle of working out after FI breakdown, and when arc breakdown occurs, processor 1 removes clock pulses from timer 4, as a result of which control pulses at its output are absent, which provides a pause in the voltage of ESP 8.

The adjustment angle is then increased by the magnitude of the accelerated rise angle FD and is maintained, for example, by two half-cycles of the mains voltage. Then, the angle formed at the first detection of a decrease in voltage, below 5 kV, i.e. F + FI. If, during the four half-periods of the network since the moment of occurrence of a breakdown, repeated breakdown did not occur, then the FD increases, for example, by 1%, otherwise the FD decreases, for example, by 10%. The FD value can be both positive and negative, and corresponds to the optimal rate of voltage recovery after a breakdown.

Regulation of the rate of increase of the angle of adjustment can be carried out according to the following algorithm. After each interrogation of the sensors 6 and 7 of the electrostatic precipitator 8, the processor 1 sums the received values of voltage and current during the time averaging interval (about 2 minutes). By the end of the averaging interval, the sums characterize the average values of the voltage and current of the electrostatic precipitator over a given interval. Comparing the obtained values of the average voltage and the current of the electrostatic precipitator with the data obtained in the previous interval of averaging, at a different rate of increase

the control angle is decided to invert the direction of the change in the rate of rise of the control angle for the next optimization step (average interval), if the average voltage

in the current interval less than the average voltage in the previous interval, or the current in the current interval exceeded the current in the previous interval more than a predetermined value (for example, 2% of the nominal

power supply current). Otherwise, the direction of change in the rate of increase of the control angle for the next interval will remain the same.

Claims (2)

1. A control method for an electrostatic precipitator power unit consisting of controllable valves and a step-up rectifier unit, consisting of measuring the voltage and current of the electrostatic precipitator and averaging the measured values at a given time interval, increasing the control angle of the controlled valves, fixing the spark and arc breakdowns with N the subsequent stepwise decrease in the angle of control of controlled valves to the angle of working out after the spark breakdown and the removal of the supply voltage for a predetermined time interval with the subsequent increase in the angle of adjustment of the controlled valves to the angle of accelerated rise for a given number of periods of the supply voltage after the arc breakdown, exe and with the fact that, with a view Increasing the degree of gas purification, the value of the accelerated lifting angle changes according to the condition of the occurrence of secondary breakdowns for a time longer than the supply time to the controlled gates of the sum of the angle adjustment and accelerated lifting angle for 1-2 periods of the supply network, while in the absence of secondary breakdowns the accelerated lifting angle is increased by fixed steps equal to 1% of Q is the maximum angle of adjustment, and when a secondary breakdown occurs, the angle of accelerated rise is reduced by two or more specified steps. 2. A method according to claim 1, characterized in that the rate of increase of the control angle is continuously changed, and the direction of change of said speed is reversed if the average voltage on the electrostatic precipitator in the current averaging interval is lower than the average voltage on the electric filter in the previous filter in the current averaging interval averaging interval or average current vi higher than the average current in the previous filter in the current interval of the average interval by a given magnitude above the average current in the electro-NU ( Control