As the core equipment of the power system, the stable operation of transformers directly determines the safety and continuity of power supply. However, in long-term use, affected by factors such as environment, load, and maintenance, various faults are inevitable. Among them, 2500 kva transformer and 10kv distribution transformer, as commonly used equipment in industrial production and power distribution, their fault diagnosis is the key to ensuring the stability of the power system.
I. Appearance Faults
Appearance faults are the most easily detected transformer fault phenomena, which can be initially judged without professional instruments. Whether it is 2500 kva transformer, 10kv distribution transformer or other specifications of transformers, the following situations should be focused on:
🔹 Oil leakage of oil-immersed transformers: Oil stains appear at the tank joints, oil pipe interfaces or valves, and oil drops may leak in severe cases. This will lead to a drop in the liquid level of insulating oil, affecting heat dissipation and insulation performance. Long-term leakage may cause equipment overheating. Especially for 2500 kva transformer with large load, if the oil leakage problem is not handled in time, it may lead to serious equipment damage.
🔹 Shell deformation or corrosion: The shell is dented, damaged, or the surface coating falls off and rusts. It is mostly caused by external impact and erosion of harsh outdoor environments (rain, snow, salt spray), which may damage the sealing performance and cause internal moisture. It has a more obvious impact on 10kv distribution transformer installed outdoors. The humid environment is easy to accelerate the aging of internal components.
🔹 Insulator damage or contamination: The insulators at the high-voltage terminals are cracked, damaged, or covered with a lot of dust and oil stains. It will reduce the insulation strength, may cause flashover discharge, and even cause short-circuit faults. This is also a common appearance hidden danger of 10kv distribution transformer used outdoors.
🔹 Winding discoloration of dry-type transformers: The epoxy resin cast windings have yellowing and blackening marks, which are mostly caused by overheating of the windings due to overload and poor heat dissipation. In severe cases, it may be accompanied by cracking of the insulation layer. This situation is more likely to occur when 2500 kva transformer operates under long-term high load.
II. Abnormal Operation Sound
A normally operating transformer will emit a uniform and stable "buzzing" electromagnetic sound. Once abnormal sound occurs, it is a typical transformer fault phenomenon that needs to be vigilant. This feature is particularly prominent in 2500 kva transformer and 10kv distribution transformer:
🔹 Increased abnormal noise: The "buzzing" sound becomes significantly louder and duller, which is mostly caused by overload operation, loose iron core or abnormal voltage. In the long run, it may cause winding overheating and insulation aging. For large-capacity equipment such as 2500 kva transformer, the abnormal noise caused by overload will be more obvious, and the load needs to be adjusted in time.
🔹 Bursting/crackling sound: Suddenly emitting "crackling" discharge sound or "bursting" sound may be caused by winding insulation breakdown, iron core short circuit, or insulator surface flashover discharge, and the machine needs to be shut down for inspection immediately. If this fault occurs in 10kv distribution transformer, it may affect the normal power supply of surrounding distribution lines.
🔹 Irregular noise: Accompanied by "sizzling" and "rustling" sounds, it may be caused by loose internal components, foreign objects entering the cabinet, or poor contact of terminals. Long-term operation is easy to cause local overheating. Whether it is 2500 kva transformer or 10kv distribution transformer, such noise indicates that internal components may be abnormal and need to be checked in time.
III. Parameter Abnormalities
Checking the operating parameters with monitoring instruments is the key to accurately judging transformer fault phenomena. Focus on the following data fluctuations, which are particularly important for the fault diagnosis of 2500 kva transformer and 10kv distribution transformer:
🔹 Excessively high oil temperature: The oil temperature of oil-immersed transformers exceeds 85℃, and the winding temperature of dry-type transformers exceeds 110℃, which continues to not drop. It is mostly caused by heat dissipation system faults (radiator blockage, fan damage), overload operation or internal short circuit. Due to its large capacity and high heat dissipation demand, 2500 kva transformer needs to focus on monitoring the problem of excessively high oil temperature.
🔹 Unstable voltage/current: The output voltage fluctuation exceeds ±5%, or the current fluctuates up and down, and the three-phase current is unbalanced. It may be caused by poor contact of the tap changer, inter-turn short circuit of the winding, or fluctuation of the external power supply system. As the core equipment of power distribution, 10kv distribution transformer's unstable voltage and current will directly affect the normal operation of terminal electrical equipment.
🔹 Abnormal oil level: The oil level of the oil conservator of the oil-immersed transformer is lower than the minimum scale, or drops sharply suddenly. In addition to oil leakage, it may also be caused by the contraction of oil volume due to sudden changes in oil temperature, and it is necessary to check for hidden leakage. This problem needs to be focused on both 10kv distribution transformer used outdoors and large-capacity 2500 kva transformer.
IV. Core Component Faults
Core component faults are deep transformer fault phenomena. If not handled in time, they may lead to equipment shutdown or even scrapping. The core component faults of 2500 kva transformer and 10kv distribution transformer need to be highly vigilant:
🔹 Tap changer fault: When adjusting the voltage, the hand feel is stuck, cannot be positioned, or the voltage does not change after adjustment. It is mostly caused by oxidation of switch contacts and wear of contacts, which will cause unstable voltage output and even short circuit in severe cases. It has a particularly obvious impact on the voltage regulation of 10kv distribution transformer, which may lead to abnormal distribution voltage.
🔹 Iron core fault: The iron core grounding current is too large, or local overheating occurs. It may be caused by damage to the iron core insulation and multi-point grounding, leading to increased eddy current loss and burning of iron core laminations in the long run. This fault is more likely to occur when 2500 kva transformer operates under long-term high load, which will greatly reduce the service life of the equipment.
🔹 Winding fault: The DC resistance of the winding is unbalanced, and the insulation resistance decreases. It is mostly caused by winding moisture, inter-turn short circuit, and loose lead joints, which is manifested by equipment heating, increased energy consumption, and even tripping. Whether it is 2500 kva transformer or 10kv distribution transformer, winding fault is the core hidden danger affecting the stable operation of the equipment.
V. Other Auxiliary Faults
In addition to the above main faults, the following auxiliary system faults are also common transformer fault phenomena that need extra attention, which are equally important for the normal operation of 2500 kva transformer and 10kv distribution transformer:
🔹 Cooling system fault: The radiator of the oil-immersed transformer is blocked, and the cooling fan of the dry-type transformer does not start. It will lead to a decrease in equipment heat dissipation efficiency, which in turn causes an increase in oil temperature/winding temperature and limits the load capacity. Due to the large heat generation of 2500 kva transformer, the cooling system fault will quickly lead to equipment overheating and needs to be repaired in time.
🔹 Abnormal action of protection device: The circuit breaker trips frequently, the fuse blows, or the relay protection device gives false alarms. It may be caused by internal faults of the equipment or failure of the protection device itself, which needs to be checked in conjunction. For 10kv distribution transformer, abnormal protection device may lead to frequent interruption of distribution lines and affect the continuity of power supply.
JINSHANMEN TECHNOLOGY CO., LTD warmly reminds: Regular inspection of transformers and timely identification of various fault phenomena are the keys to extending the service life of equipment and ensuring the stability of power supply. Whether it is 2500 kva transformer, 10kv distribution transformer or other specifications of transmission and distribution equipment, we can provide professional production, maintenance guidance and technical support to help enterprises avoid equipment fault risks and ensure the smooth progress of production.