Tranzistoran di dema divê bixweberî ve hatî şarhkirin ji bo dawîkariya weha bi hêza nîşangkirin û baran destnîşan da ku navê "jiyanîna tranzistora" dike. Materyalên bikaranîn a tranzistorên şirîn gotin di du kategoriya sereke de: materyalên sermetî û materyalên izolekirin. Materyalên sermetî derbasdarî ne ku hewceyên girîng werin, lê materyalên izolekirin hêz dikin da ku çêr bin vekirin û zevzekin ku hewa herî hilbijêre birayê yek demekê. Buna, hewa yek demekê ya herî girîng e ku jiyanîna tranzistora were têkiliyê. Di her cihê de, jiyanîna tranzistora dikare yejiye jiyanîna materyalên izolekirin be.
Hewa pêşketin jîyanîna tranzistora werin digerîne
Tranzistoran di dema divê bixweberî ve hatî şarhkirin ji bo dawîkariya weha bi hêza nîşangkirin û baran destnîşan da ku navê "jiyanîna tranzistora" dike. Materyalên bikaranîn a tranzistorên şirîn gotin di du kategoriya sereke de: materyalên sermetî û materyalên izolekirin. Materyalên sermetî derbasdarî ne ku hewceyên girîng werin, lê materyalên izolekirin hêz dikin da ku çêr bin vekirin û zevzekin ku hewa herî hilbijêre birayê yek demekê. Buna, hewa yek demekê ya herî girîng e ku jiyanîna tranzistora were têkiliyê. Di her cihê de, jiyanîna tranzistora dikare yejiye jiyanîna materyalên izolekirin be.
Herî vekirina wêjî û nasnameyên aslen a materyalên izolekirin bi dilindin xwebûn di ser rûnd û hewa herî girîng de yejiye "dilindin". Rêja dilindin bigire ji wan paragrafên:
Hewa materyalên izolekirin.
Nisandina abî materyalên izolekirin.
Ji bo tranzistoran bi rozhînê, hizma oksîjen ên li rozhînê werin pirînin.
Ew sazên se dikan jiyanîna tranzistora were têkiliyê. Amûra û kerk û wergirtina dike ku heta ma u hewa 95°C li warên bibin, jiyanîna tranzistora dike 20 sal. Ji bo rêja nîşangkirin û jiyanîna, "qayda 8°C" dike niha kirin: ji bo her 8°C berbiyayîn hewa warên, jiyanîna tranzistora werin niha kirin.
Most power transformers in China use oil-paper insulation, i.e., Class A insulation. For Class A insulated transformers, under normal operation, when the ambient air temperature is 40°C, the maximum operating temperature of the windings is 105°C.
According to relevant data and practice:
When the transformer's insulation operating temperature is 95°C, its service life is 20 years.
When the transformer's insulation operating temperature is 105°C, its service life is 7 years.
When the transformer's insulation operating temperature is 120°C, its service life is 2 years.
The internal insulation temperature of a transformer, under essentially constant voltage, mainly depends on the magnitude of the load current: higher load current leads to higher insulation temperature, while lower load current results in lower insulation temperature.
When a transformer is overloaded or operates at rated load during summer, its internal insulation runs at high temperatures, accelerating life loss. When the transformer operates under light load or at rated load during winter, its internal insulation runs at lower temperatures, slowing down life loss. Therefore, to fully utilize the transformer's load capacity throughout the year without affecting its normal service life, the monthly load can be appropriately adjusted.
High voltage accelerates transformer aging
For example, regulations stipulate that the operating voltage of a transformer must not exceed 5% of its rated voltage. Excessively high voltage increases the magnetizing current in the transformer core, may cause core saturation, generate harmonic flux, further increase core losses, and lead to core overheating. Excessively high voltage also accelerates transformer aging, shortening its service life; therefore, the operating voltage of a transformer must not be too high.
When insulating material ages to a certain extent, under the influence of operational vibration and electromagnetic forces, the insulation may crack, making electrical breakdown faults more likely and reducing the transformer's service life.
Adjusting transformer load to achieve ideal service life
The internal insulation temperature of a transformer, under essentially constant voltage, mainly depends on the magnitude of the load current: higher load current leads to higher insulation temperature, while lower load current results in lower insulation temperature.
When a transformer is overloaded or operates at rated load during summer, its internal insulation runs at high temperatures, accelerating life loss. When the transformer operates under light load or at rated load during winter, its internal insulation runs at lower temperatures, slowing down life loss. Therefore, to fully utilize the transformer's load capacity throughout the year without affecting its normal service life, the monthly load can be appropriately adjusted.
Proper maintenance helps maximize transformer service life
It is well known that once a transformer fails, not only are repair costs and downtime expenses substantial, but rewinding a coil or rebuilding a large power transformer can take 6 to 12 months. Therefore, a proper maintenance program will help the transformer achieve maximum service life.
Three key points of a good maintenance program
Installation and operation
A. Ensure the load remains within the design limits of the transformer. For oil-cooled transformers, carefully monitor the top-oil temperature.
B. The transformer's installation location should be suitable for its design and construction standards. If installed outdoors, ensure the transformer is suitable for outdoor operation.
C. Protect the transformer from lightning strikes and external damage.
Oil testing
The dielectric strength of transformer oil decreases sharply as moisture content increases. As little as 0.01% water content can reduce its dielectric strength by nearly half. Except for small distribution transformers, oil samples from all transformers should be regularly subjected to breakdown tests to properly detect moisture and remove it through filtration.
Fault gas analysis in oil should be performed. Using an online monitoring device for eight fault gases in transformer oil, continuously measure the concentration of gases dissolved in the oil as faults develop. By analyzing the types and concentrations of these gases, the type of fault can be determined. Physical property tests of the oil should be conducted annually to verify its insulating performance, including tests for dielectric breakdown strength, acidity, interfacial tension, etc.
