Power distribution Equipment is a critical component of the power system, and the reliable operation of distribution equipment is essential for ensuring safe and dependable power supply in the distribution network. Regular inspections of distribution equipment enable operators to monitor its operating condition, promptly identify defects or abnormal conditions, and thereby prevent accidents from occurring or escalating, while implementing effective measures to ensure the safe and reliable continued operation of the equipment. Accordingly, Mr. e has analyzed the key points of operation and maintenance for distribution equipment that are often overlooked in daily work. Let us now explore the fundamental knowledge of distribution equipment operation and maintenance.

　　1 Operation and Maintenance of Dry-Type Transformers

　　In practical applications, proper maintenance of dry-type transformers to ensure their reliable operation is a key concern for distribution operators.

　　1.1 Operation of Dry-Type Transformers

　　The safe operation and service life of a dry-type transformer depend to a large extent on the safety and reliability of the winding insulation. When the winding temperature exceeds the insulation’s thermal endurance limit, insulation aging occurs, which shortens the insulation’s lifespan and is one of the primary causes of abnormal transformer operation. Therefore, monitoring the transformer’s operating temperature and implementing appropriate alarm and control functions are of critical importance.

　　1.2 Maintenance of Dry-Type Transformers

　　The operating temperature of distribution equipment is directly related to the service life of dry-type transformers. Power distribution Operators should pay particular attention to inspecting and maintaining the fan’s automatic control system, over-temperature alarm, trip system, and temperature display system. Dry-type transformers exhibit good moisture resistance; however, dust in the air can adhere to the insulation surface, reducing the surface flashover voltage, and humid weather may lead to dust-induced flashovers. Therefore, regular dust removal and inspection for signs of discharge are essential. During operation, dry-type transformers should be monitored for abnormal noises and for any abnormalities in busbar connections and cables; any detected anomalies must be addressed promptly to prevent accidents.

　　2 Operation and Maintenance of Power Capacitors

　　2.1 Operation of Power Capacitors

　　 Power distribution When operating power capacitors, it is essential to ensure both safe and economical operation. Special attention must be paid to the following: power capacitors shall operate at their rated voltage and must not exceed 1.05 times the rated voltage; however, they may be operated at 1.1 times the rated voltage for a maximum of 4 hours. If the operating voltage exceeds 1.1 times the rated voltage, the capacitor must be immediately taken out of service. Overvoltage imposes an excessive load on the capacitor, which can lead to overheating of internal components or even catastrophic failure. Furthermore, it is crucial to avoid overcompensation and the resulting ineffective reverse power flow that occurs when load equipment shuts down, as this leads to unnecessary power losses.

　　2.2 Maintenance of Power Capacitors

　　To ensure the normal operation and extended service life of power capacitors, please pay attention to their routine maintenance during daily operation.

　　2.2.1 Visual Inspection

　　Perform a visual inspection of power capacitors in operation to check for oil spraying, oil leakage, bulging, cracking, and overheating of connection terminals. If any of these abnormalities are detected, immediately shut down the equipment to prevent accidents.

　　2.2.2 Voltage Value Inspection

　　During operation, power capacitors experience voltage fluctuations due to changes in the supply load. To ensure safe operation, it is advisable to use automatic switching devices; however, in the event of an automatic failure, manual switching may be employed, requiring the operator to adjust the switching based on the load conditions. Failure to do so can result in overcompensation or reverse reactive power flow.

2.2.3 Current Value Inspection

　　To extend the service life of power capacitors, they must be operated at their rated current; however, operation at or below 1.3 times the rated current is permitted. Operation at more than 1.3 times the rated current is strictly prohibited. This is because excessive current flowing through a power capacitor can cause it to burn out.

　　2.2.4 Inspection of Protective Devices

　　Each capacitor bank is equipped with a fuse for protection; the fuses should be inspected regularly to check for loose or overheated terminal connections. Any abnormalities must be addressed promptly to prevent overheating of the fuse holder and insulation failure, which could lead to ground faults.

　　3 Operation of Current Transformers

　　A current transformer, also known as an ammeter transformer, has its primary winding connected in series with the primary circuit under measurement and features a small number of turns, while its secondary winding is connected in series with the measuring instrument’s current coil and has a large number of turns. During operation, the secondary impedance of a current transformer is low; its function is to step down a high primary current to a lower secondary current, with the rated secondary current typically being 5 A. The current transformer must operate at its rated conditions; if it is operated beyond its rated capacity, measurement errors will increase and instrument readings will become inaccurate. Furthermore, overheating of the secondary winding will accelerate insulation aging and may even lead to winding burnout.

　　3.1 Maintenance of Current Transformers

　　Distribution system operators shall conduct regular patrols of current transformers, inspecting for overheating at connections, abnormal noises, unusual odors, signs of insulation breakdown or discharge, and cleanliness of critical components. Any such abnormalities must be addressed promptly to prevent accidents. The secondary circuit of a current transformer must never be left open; one end of the secondary winding must be reliably grounded.

　　3.2 Operation of Voltage Transformers

　　Instrument transformers, commonly referred to as “potential transformers,” operate on the principle of electromagnetic induction and have a basic structure identical to that of conventional power transformers. Such transformers may be operated continuously at their rated capacity, and they can also be operated continuously when the operating voltage exceeds the rated value by up to 10%. During operation, a step-down transformer that is effectively in no-load condition must not experience any short-circuit conditions on its secondary side.

　　3.3 Maintenance of Voltage Transformers

　　 Power distribution To ensure the normal operation of transformers, distribution operators conduct regular inspections to verify that the transformer insulation is clean and free from cracks, damage, partial discharge, severe oil immersion or leakage, and abnormal noises. If any of these conditions are detected, the root cause must be promptly identified and addressed.

　　The above is an introduction to the basic knowledge of distribution equipment operation and maintenance. For more information, please feel free to contact us at any time!