How to deal with the electrostatic precipitator reporting undervoltage or short circuit fault

Electrostatic precipitators. Report undervoltage or short circuit fault, in this case, strengthen the ash, power failure, self-test, restart, if necessary, shorten the rapping cycle, cathode, anode need to be adjusted, serious power field can be stopped, change the continuous rapping mode, and then put into use after a period of time.

Electrostatic precipitators are thermal power plants.

The function of the necessary supporting equipment is to remove the particulate smoke in the flue gas discharged from the stove or oil-fired boiler, so as to greatly reduce the emission into the atmosphere.

in the amount of soot, which is to improve environmental pollution and improve air quality.

important environmental protection equipment. It works on the principle that when the flue gas passes through the flue in front of the main structure of the electrostatic precipitator, the smoke and dust are positively charged.

The flue gas then enters the electrostatic precipitator channel, where a multi-layer cathode plate is set. Due to the mutual adsorption of the positively charged smoke and the cathode electric plate, the particle smoke in the flue gas is adsorbed on the cathode, and the cathode plate is hit regularly, so that the smoke and dust with a certain thickness fall in the ash hopper under the structure of the electrostatic precipitator under the dual action of self-weight and vibration, so as to achieve the purpose of removing the smoke and dust in the flue gas. Due to the large power of thermal power plants, such as 600,000 kilowatt units, the amount of coal burned per hour is about 180t, and the amount of smoke and dust can be imagined.

Therefore, the corresponding electrostatic precipitator structure is also relatively large. The cross-sectional size of the main structure of the electrostatic precipitator used in the general thermal power plant is about 25 40 10 15m, if the height of the ash hopper is added 6 meters, as well as the height of the smoke transportation space, the height of the entire electrostatic precipitator is more than 35 meters, for such a huge steel structure body, it is not only necessary to consider the autonomy, smoke and dust load, and wind load.

**Static and dynamic analysis under load. At the same time, the stability of the structure must also be considered.

The main structure of the electrostatic precipitator is a steel structure, all of which are made of section steel.

Welded, the outer surface is covered with skin (thin steel plate) and insulation material, for the convenience of design, manufacture and installation. Structural design.

It adopts a layered form, and each piece is composed of a plurality of main beams of frame type, and the pieces are connected by girders. In order to install the skin and insulation layer, the secondary beam is welded between the main beams, and for such a huge structure, how to connect them according to the physical object, its workload and the number of elements will be very huge. According to the actual design requirements of the project and the design of the main structure of the electrostatic precipitator, the structural strength, structural stability and the maximum displacement of the main beam of the suspension cathode plate are mainly investigated.

For the local area, the fatigue damage of the connection between the cathode plate and the main beam under long-term periodic blows was mainly investigated. The best frequency selection for the soot shedding on the cathode plate; The best choice of the stiffness between the surface skin (thin plate) of the structure and the main and secondary beams under wind loading, etc.

The internal instability of the electric field leads to low secondary voltage feedback, always like this in the detection cycle, it will be pressured for a long time, short circuit is the instantaneous discharge of the internal plate, the current is too large, and the electrostatic precipitator has a lot to do with the operating conditions.

The fault phenomenon of electrostatic precipitator reporting undervoltage or short circuit must be determined according to the model of the manufacturer of the original high-voltage silicon rectifier equipment, under normal circumstances, it can be judged that it is a problem of the high-voltage control cabinet, and a false load can be connected to the output circuit of the control cabinet during maintenance, and the false load is connected in series with two 150W lamps, if the false load can be normal and stable and slowly brighten, it means that the previous circuit of the high-voltage control cabinet is normal, and the fault is mainly caused by the current and voltage feedback circuit or the silicon rectifier transformer. If the false load can not be lit, it means that there is a problem with the control circuit in the high-voltage control cabinet, and it is best to report to the manufacturer for maintenance in order to prevent further expansion of the fault.

It means that there is too much dust on the plate, and the beating should be strengthened to make the ash fall off.

I'll add a little more: pay attention to whether there is an air leak at the location of the fault. In addition, is it that the plate is more deformed?

Troubleshooting methods of electrostatic precipitator high-voltage power supply system: 1) The open-circuit test hits the isolation switch to the position where it is cut off from the electric field, slowly boosts the voltage from the control cabinet, and pays attention to the indication of the primary current. Normally, this indication is small.

2) Check and test 1, the insulation resistance of the core to the ground is 0; 2. Low insulation resistance to the ground: 400m; 3. High insulation resistance to the ground: 1000m; 4. Sampling resistance 78m (U2=60 80kV transformer).

5. Forward and reverse resistance of the silicon stack: Check the forward and reverse polarity of the silicon stack with a 2500V shake meter, if the reverse phase resistance value is "0", it may be the breakdown of the silicon stack or capacitor. If the capacitor resistance is "0", the capacitor is damaged; If the capacitance resistance is normal, the silicon stack is damaged.

6. DC resistance value of high-voltage winding. Compare the measured DC resistance value of the high-voltage winding with the DC resistance value on the label, if the difference is large, the winding is problematic; If the difference is not significant, it must be further judged by testing (i.e., variable ratio test). 3) Ratio test to remove the high-voltage winding and silicon stack board connection line (unilateral), use a voltage regulator to input about 5 10V from the low-voltage side, observe the change of primary current, if there is an obvious indication, it means that there is a short circuit, and measure the induced voltage of each high-voltage winding with a multimeter.

According to the principle of transformer, the same turn should be the same voltage, if the high-voltage winding has the same voltage with the same turn, and i1 has obvious changes, then the low-voltage winding is judged to have a short circuit. For high impedance, after judging that there is a problem with the low-voltage winding, it is also necessary to energize separately and compare the parameters on both sides for further judgment.

1. The electric field produces a serious flashover.

Cause of failure: The spacing between the cathode and anode changes, resulting in a large decrease in the insulation performance between the two phases.

Exclusion measures: After the electric field trips, use a 2500V megger after the electric field is discharged.

Check the insulation resistance.

value, after verification, it is necessary to manually check and eliminate debris in time and adjust the spacing.

2. Irregular changes in secondary current.

Cause of failure: Electrode dust accumulation, a certain part of the pole distance becomes smaller, resulting in spark discharge.

Exclusion measures: Removal of accumulated dust.

3. Periodic changes in secondary current.

Cause of failure: After the corona wire is broken, the residual part shakes.

Exclusion: Replace the disconnection.

4. There are a lot of sparks.

Cause of failure: manhole air leakage, wet air ingress, insulator.

Dirty. Poor contact on the secondary side inside the transformer or rectifier bridge diode.

Open. The airflow is not evenly distributed.

The heteropole distance becomes smaller.

The ash hopper sewage is too high.

The damping resistor is broken and discharged.

Exclusion: Replace the airflow distribution plate.

Adjust the heteropole distance. Tighten drainage.

Replace the damping resistor.

5. The primary and secondary currents and voltages are normal, but the dust removal efficiency is not high.

Cause of failure: The distance between the different poles is too large.

The airflow distribution is uneven, and the distribution plate is blocked with ash.

The large air leakage rate changes under working conditions, so that the flue gas velocity increases, the temperature drops, and the charge performance of dust particles becomes weaker.

The control parameters are not set properly.

The flue gas conditions entering the wet electrostatic precipitator do not meet the original design conditions of this equipment, and the working conditions change.

The equipment has mechanical faults, such as poor pump function, etc.

Exclusion measures: Adjust the heteropolar distance.

Replace the distribution plate.

Repair welding plugs the air leakage.

Adjust the parameters. According to the correction curve, the efficiency is assessed according to the actual working conditions.

6. The primary voltage regulation is normal when the voltage is boosted, and the secondary voltage is intermittent and unavailable, accompanied by discharge sound.

Cause of failure: rectifier secondary coil and rectifier silicon stack open circuit and virtual solder joint.

The safety distance of the high-voltage lead to the housing is insufficient.

There is an open circuit in the DC sampling voltage divider circuit.

Troubleshooting measures: The core checks the rectifier and will troubleshoot.

Check and install the high-voltage leads.

The core is inspected for rectifier and repaired.

1. Dust accumulation on plates and pole lines can be solved by appropriate rapping.

2. Anti-corona phenomenon.

3. The short circuit of the electric field is generally caused by the short circuit caused by the broken pole wire.

4. The ash under the ash hopper is not smooth, resulting in ash accumulation in the ash hopper, and the output voltage will be low.

5. Defects in the secondary and control loops of electrostatic precipitators.