In-service transformers shall be patrolled and inspected in accordance with regulations, with real-time monitoring of operation status and strict compliance with operation standards to ensure safe and stable operation.
1. Operation Standards
(1) Allowable Temperature
Based on the two-year operation data of a 1600KVA dry-type transformer currently in operation at the new plant, the transformer runs normally at a temperature of about 105℃ when the current reaches 2100A under peak summer load. For dry-type transformers, the normal allowable temperature shall not exceed 110℃, with a maximum upper limit of 120℃.
(2) Allowable Load
The operating load of a transformer shall be kept below its rated capacity (i.e., the apparent power of the transformer). Generally, the transformer is not allowed to operate beyond the rated capacity, while normal overload operation is permitted under specific conditions. The overload rate shall not exceed 10% of the transformer’s rated capacity, and close attention shall be paid to the temperature rise during overload operation.
(3) Three-Phase Unbalanced Load
In case of three-phase load unbalance, the current of the phase with the maximum load must be closely monitored. If severe three-phase current unbalance is detected, the load of single-phase electrical equipment shall be adjusted and evenly distributed in a timely manner to restore normal operation.
(4) Allowable Voltage Fluctuation
The supply voltage of the transformer shall generally not deviate by more than 5% from its rated value. For the 10KV power line, the operating voltage must be strictly kept within the allowable upper and lower limits of the rated voltage.
2. Transformer Routine Maintenance
(1) Real-time Load Monitoring
On-duty operators shall monitor the operating load of the transformer according to the indications of voltmeters, ammeters and thermometers, and report any abnormal data or operation status to the relevant department in a timely manner.
(2) Peak Summer Maintenance
During the peak load period in summer, strengthen the patrol and real-time monitoring of the transformer’s load current and operating temperature. Regularly check the operation status of cooling fans, and immediately troubleshoot and handle any abnormal operation to avoid temperature rise faults.
(3) Abnormal Noise Monitoring
Keep monitoring the operating noise of the transformer during daily operation, and conduct a comprehensive inspection in time if abnormal noise such as abnormal hum or impact sound is found.
(4) Connection Part Inspection
Regularly check the transformer’s lead joints, cables, busbars and other key connection parts for signs of overheating, oxidation and corrosion, and repair or replace the damaged parts in a timely manner.
(5) Regular Dust Removal and Inspection
Conduct dust removal on the top and bottom circulating air vents of the transformer room every year during external power outages to ensure unobstructed air circulation. Wipe off dust on the surface of the winding casting with a clean cloth, check the casting for cracks and surface damage caused by overheating, and inspect the fixing bolts at the bottom corners of the transformer windings for loosening and retighten them if necessary.
(6) Safety Protection of Transformer Room
Avoid opening the front and rear doors of the transformer room as much as possible during normal operation to prevent small animals (such as birds, mice, etc.) from entering the room and causing short circuit and other safety accidents.
(7) Environmental Sanitation Management
Keep the environmental hygiene around the transformer room clean at all times, and no sundries or heavy objects shall be placed around the transformer to ensure unobstructed maintenance and heat dissipation space.
(8) Damp-proof and Water-proof Inspection
Regularly check the cable trench under the transformer room for water accumulation, which may cause dampness in the transformer’s operating environment. If water accumulation is found, drain and handle it in a timely manner to prevent moisture absorption by the transformer windings and avoid insulation performance degradation.
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