What Happens If The Trip Protection Of A Dry-type Transformer Is Not Configured Correctly?

In a power distribution system, the outdoor dry type transformer system relies on multiple protection devices to maintain safe operation. Improper setting of protection parameters can trigger a chain of failures. If the overcurrent protection setting is too high, the thousands of amperes of current generated by a short circuit in the coil cannot be interrupted in time, causing the copper conductor temperature to surge to over 400°C within 0.1 seconds. This leads to carbonization of the insulation material, releasing toxic gases, and cracking or even bursting of the epoxy resin casting. If the setting is too low, frequent malfunctions occur, triggering circuit breaker dry type power transformer tripping even during normal load fluctuations or capacitor switching.

The sensor installation location in the temperature protection system directly affects the response speed of circuit breaker 25 kva dry type transformer. Embedded thermometers should be placed in the middle area where the coil temperature rises the most, 3-5 cm away from the iron core surface. The alarm threshold for the temperature controller should be set at 130°C, and the trip threshold at 150°C. Insufficient configuration leads to continuous coil overload, causing a decrease in insulation class. For Class F insulation materials, the lifespan is halved for every 8°C increase above 155°C. A cooling fan malfunction without interlocking tripping results in loss of heat dissipation, causing local temperatures to exceed 200°C and leading to insulation breakdown.

Improperly set differential protection criteria can lead to misjudgments. Inrush current can reach 6-8 times the rated current, lasting 0.5-1 second; the second harmonic restraint coefficient should be set within the range of 15-20%. An excessively steep ratio differential slope can cause protection failure during external faults; even with an internal inter-turn short-circuit current reaching 300 amperes, the 3 phase dry type transformer tripping action may still not be triggered.