Imported air compressor burning accident analyst Shu Ying Zhao Fujun Zhang Li (Hebei Datang Wangtan Power Generation Company, Hebei Leting 063611) 2 Failure inspection process and analysis 2.1 After the ash air compressor protection trip, protect the on-site inspection of the protection device's event record and remote signal record and protection settings. Since the protection device accident record is only saved 4 times, the record is as follows for the first time: 1:16m "215mS zero sequence protection action trip 滗 second: 1:16:43" 189mS zero sequence protection action trip; third time a: 1645" 164ms overheat protection action trip 滗 four times: 1:17 37" 398mS zero sequence protection action trip. Event action time (>) action name action action name over-current protection jump w zero sequence protection jump w over-current protection jump M zero-order protection jump M over-current protection jump M zero-order protection jump W over-current protection jump M zero sequence Protection hop M overcurrent protection 踵N zero sequence protection hopping M overcurrent protection hopping w zero sequence protection hopping w overcurrent protection tripping zero sequence protection hopping M overcurrent protection hopping W overcurrent protection hopping M zero sequence protection hopping W f hopping zero Sequence protection jump M overheat protection action zero sequence protection jump M zero sequence protection jump W event record zero sequence protection action time is. 5S is different from the previous time interval by 710ms analysis, switch trip time (45mS) + protection return time (80ms) + switch re-closing time (60ms) + zero sequence re-operation time (500ms) + error = 710mS. The overcurrent protection action time in the event record is 6S. If it is restarted, it needs to avoid the start event 6S. From the event record, enumerate 1:15:52"249 overcurrent protection trip and 1:16:05"255 overcurrent protection trip interval 13" is consistent with the analysis. 2.2 After the on-site search, the signal of the closing command 103 given by the local PLC of the air compressor is the long-term closing command. When the 6kV switch of the air compressor is tripped, the air compressor can be sent to the local PLC at 4~5S. The subsequent shutdown command is another reason for the 6kV switch to jump in multiple times. In addition, the F+C circuit, that is, the fuse + contactor circuit breaker itself does not have the electrical anti-skip function, which is also a cause of the expansion accident. 2.3 Ingersoll Rand air compressor is the closing command of the high-voltage power switch for the imported equipment air compressor. The running command is long-term. When the air compressor is manually stopped or the fault stops, the air compressor PLC closing command recovers and takes out the long-term. The trip command makes the high-voltage power switch completely disconnected, so the high-voltage switch configured abroad is an electric-contact type of contactor switch, that is, the closing command is in, the contactor is electrically closed, and the closing command disappears. Prevent the power supply from being re-powered to cause damage to the air compressor. The switches designed by domestic power plants are generally high-voltage vacuum circuit breakers and fuses plus contactor type F+C circuit switches. Because of the small capacity of air compressors, the power plant uses Siemens 3TL61 F+C contactors. The single device requires an external closing pulse to be closed. At the beginning of the design, the closing current reaches 6A, and the integrated protection and monitoring device cannot disconnect the 6A current, and the auxiliary contact of the contactor is also disconnected. Therefore, the closing and closing relay of the closing relay is turned on and off by the measuring and controlling device. At the same time, add a time relay, delay the closing of the closing relay to ensure that the 3TL61 sends a closing pulse. Once the switch is closed, the relay is closed by the auxiliary contact to close the closing circuit. In summary, when designing the air compressor control circuit, the air compressor manufacturer should consider the switchgear protection action to immediately feedback to the PLC protection action signal but use the long-term closing command and long-term trip command for the imported air compressor system. The hidden dangers of the accident are not fully realized. 2.4 In the PLC logic loop through the judgment and other factors, the trip command time is too long (4~ boiler air compressor and ash air compressor control logic error, air compressor control logic and 6KV high voltage switch control and protection should be coordinated. The high-pressure switch issued by the air compressor control system is a long-pulse signal air compressor fault protection action. The closing pulse is long-lived after the trip, which will cause the high-voltage switch to repeatedly burn out the air compressor. The air compressor control system is combined. The brake command is changed to a short pulse of Is. 3.2 Change the high voltage switch protection control loop. The air compressor manufacturer changes the closing command of the air compressor control system to the short pulse of Is, but if the protection action time limit of the high voltage switch is lower than Is, in the event of a fault, the coincidence phenomenon will occur after the protection action. In view of the high failure rate in the operation of the air compressor, the switch closing circuit is modified to prevent the switch coincidence in the event of a fault, and the protection action is closed. The specific measures taken are to insert a protective action blocking contact in the switch closing circuit. After the protection action, its signal contact activates the normally closed contact of the repetitive relay K2K2 before entering the closing circuit 103. Once the protection action, K2 action, the contact opens the involute closing circuit protection action signal to return after the self-holding signal has manual reset. Therefore, the closing circuit is always disconnected before manual reset. It should be noted that after the accident is removed, the operator must reset the protection action signal before closing the switch again. Due to the long-term command of the imported air compressor PLC and trip circuit, when the air compressor or motor fault protection action trips, the protection returns to cause the switch to close again. Multiple impacts will damage the air compressor motor. This is the control circuit of the air compressor itself. It must be well matched with the switch control circuit and the performance of the switch itself. In the design, it is necessary to consider the equipment damage caused by the improper cooperation of the full fat. Higher Inner Ring Ball Bearing
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Analysis of Burning Accidents of Imported Air Compressors