Sarƙunan Karkashin Jirgin Yara: Tarihi, Abubuwan da a Amfani Da Su da Ingantaccen Kirkiro

Dabbobi na Tarihin Mafi Kiyaye Dabbobi

Dabbobi na mafi kiyaye dabbobi yana da zama daɗi ake gudanar da shi waje ta hanyar jirgin sauran abubuwan kwakwai a kan. Ba a yi waɗannan abubuwa da kullum a cikin tashar aiki biyu ba. Amma, idan yadda ake faruwa mai karfi a cikin abubuwa, dabbobi na mafi kiyaye dabbobi ya faruwa karkashin, inda ya zama daɗi ake gudanar da wannan faruwar karkashi ta hanyar tsakiyar ra'ayi.

Na biyu na musamman da ke faruwa na dabbobi na mafi kiyaye dabbobi suna da duɗen magangan da suka saka tsakiya kamar zane a kan sauran abubuwan kwakwai. Idan yadda kyau a kan wannan tsakiya ya faruwa zuwa adadin daɗi, ya zama daɗi ake gudanar da faruwar karkashi, inda ya amsa abubuwa. Wannan nau'in dabbobi ana kiranta da sunan "expulsion gap" ko "protective gap."

Yadda ake faruwa na hadadawa ce kamar haka: an samun wuraren hadadawa da tsakiyar ra'ayi kamar zane a kan duɗen magangan (electrodes). Idan yadda kyau a kan wannan tsakiya ya faruwa zuwa adadin daɗi, ya zama daɗi ake gudanar da faruwar karkashi, inda ya faruza hadadawa.

Amma, ana da muhimmanci na gaba. Dabbobi na protective gap suna da zama daɗi ake gudanar da tsarin karamin birnin kasa. Idan yadda ake faruwa na faruwar karkashi mai karfi ya zama daɗi ake gudanar da wannan tsakiya (indan ya faruza tsakiya), babban makaranta ko birnin kasa bana iya samun wannan abin da shi ne - ko kuma bana iya haifar da shi da damar daɗi. Saboda haka, ana daƙe faruza karamin birnin kasa zuwa wannan tsakiya da ya faruza. Inda ya faruza tsakiya, karamin birnin kasa ya faruza karkashi daidai, wanda ya zama daɗi ake gudanar da faruwar karkashi a cikin tsarin karamin birnin kasa. Saboda haka, inda ake amfani da dabbobi na protective gap, ya zama daɗi ake gudanar da faruwar karkashi daidai a cikin tsakiya, wanda ya zama daɗi ake gudanar da faruwar karkashi.

Me kake faruwa na faruwar karkashi a cikin tsakiya da ya faruza da damar daɗi bayan ake amfani da shi? Wannan ya zama daɗi ake gudanar da dabbobi na mafi kiyaye dabbobi na farko - dabbobi na expulsion (ko tube-type) arrester. Wannan tsarin ya faruza faruwar karkashi a cikin takara, kuma ya faruza masu yanayin da za a iya faruza shi.

Amma, dabbobi na expulsion arrester suna da kalmomin da ba sai: inda ake amfani da shi, ya zama daɗi ake gudanar da karamin birnin kasa zuwa tsakiyar ra'ayi, wanda ya zama daɗi ake gudanar da faruwar karkashi daidai (short circuit).

Ainihin da ya fi shi daɗi ce, ake amfani da abin da ya zama daɗi ake gudanar da karamin birnin kasa ko kuma ake gudanar da ci gaba da karamin birnin kasa a lokacin da kyau, don in amsa faruwar karkashi, amma ya zama daɗi ake gudanar da karamin birnin kasa mai karfi (kamar hadadawa) zuwa tsakiyar ra'ayi idan yadda ake faruwa na faruwar karkashi mai karfi. A cikin kalmar, abin da ya zama daɗi ake gudanar da "intelligent switch," wanda ya sanin lokacin da ya zama daɗi ake gudanar da shi da damar daɗi. A cikin dabbobi na mafi kiyaye dabbobi, wannan "intelligent switch" ya faruza da damar daɗi a cikin abin da ake amfani da silicon carbide (SiC). Dabbobi da ake amfani da wannan abin suna kiranta da sunan valve-type arresters, saboda suna faruza kamar electrical valves.

Ya kamata a duba cewa wannan "valve" ce electrical component, ba mechanical valve kamar wadanda ake amfani da su a cikin ruwa ko karamin birnin kasa. Mechanical valves suna da damar daɗi don in amsa hadadawa, wanda ya faruza a nanosecond. Don haka, ya zama daɗi ake gudanar da electrical "valve" da ke faruza da non-linear resistor. Silicon carbide ce abin da ake faruza da damar daɗi a cikin abubuwan high-voltage applications.

Tushen tushen ya faruza da damar daɗi. An sami abin daidai da ke faruza da non-linear resistor a cikin dabbobi na mafi kiyaye dabbobi: zinc oxide (ZnO). Ya faruza kamar silicon carbide, amma ya faruza da damar daɗi da "valve" characteristics - professionally described as having better non-linearity.

Me ce non-linearity? Ana kiran cewa, ya faruza kamar haka: a lokacin da ya zama daɗi ake gudanar da karamin birnin kasa mai karfi (kamar idan yadda ake faruwa na hadadawa), resistance ya faruza zuwa adadin daɗi, kuma inda ya faruza zuwa adadin daɗi, ya zama daɗi ake gudanar da non-linearity. A lokacin da ya zama daɗi ake gudanar da karamin birnin kasa mai kyau (bayan idan yadda ake faruwa na hadadawa ya faruza, kuma tsarin karamin birnin kasa ya faruza zuwa adadin daɗi), resistance ya faruza zuwa adadin daɗi, kuma inda ya faruza zuwa adadin daɗi, ya zama daɗi ake gudanar da non-linearity.

Silicon carbide ya faruza da non-linearity, amma ba sai ideal ba. A lokacin da ya zama daɗi ake gudanar da karamin birnin kasa mai kyau, resistance ba sai zuwa adadin daɗi, wanda ya zama daɗi ake gudanar da leakage current zuwa dabbobi - kamar valve da ba ta faruza da damar daɗi, wanda ya zama daɗi ake gudanar da "trickle" of current.

Wannan alaka ce mafi inganci a cikin abin, kuma yaɗuwar ake amfani da material improvements bana iya amfani da shi da damar daɗi. Saboda haka, a lokacin da ake amfani da silicon carbide a cikin dabbobi, ana amfani da structural solutions: dabbobi ya faruza zuwa adadin daɗi a cikin line, kuma ya zama daɗi ake gudanar da shi bayan idan yadda ake faruwa na hadadawa. Wannan abin da ake amfani da shi ce series air gap. Saboda haka, valve-type arresters suna da zama daɗi ake gudanar da gap. Amma, zinc oxide valves "close tightly" a lokacin da ya zama daɗi ake gudanar da karamin birnin kasa mai kyau, kuma bana da buƙata don in ake amfani da series gap.

Idan an sami zinc oxide manufacturing technology, early limitations in "closing" capability an sami amfani da damar daɗi. Amma, saboda tarihin designs da suka faruza da gap, wasu dabbobi na zinc oxide suna da gap. Amma, gapless zinc oxide arresters suna da zama daɗi ake gudanar da majority.

Saboda zinc oxide ce metal oxide, dabbobi na ake amfani da shi suna kiranta da sunan Metal Oxide Surge Arresters (MOSA).

Bayyana Hadadawa a Tsarin Karamin Birnin Kasa

Daga abin da ake amfani da su don bayyana hadadawa, ana da uku nau'in abin: lightning rods (air terminals), overhead ground wires (shield wires), and surge arresters. Biyu na abin suna da zama daɗi ake gudanar da rods and wires, amma dabbobi na mafi kiyaye dabbobi suna da zama daɗi ake gudanar da non-linear resistors acting as "intelligent switches."

Daga abin da ake amfani da su don bayyana hadadawa, ana da uku nau'in abin: bayyana hadadawa a cikin overhead transmission lines, bayyana hadadawa a cikin substations, and bayyana hadadawa a cikin motors.

Overhead lines suna da zama daɗi ake gudanar da distance mai karfi, wanda suka faruza a cikin open areas. Don in amsa impact a cikin terrestrial life and ecosystems, suka faruza zuwa height mai karfi. Cewa, "The tallest tree catches the most wind," wanda ya zama daɗi ake gudanar da suka faruza zuwa targets for lightning. Statistics show that the majority of power grid failures are caused by lightning strikes on lines. Saboda haka, overhead lines must be protected. Amma, because of their length, absolute protection is impractical and prohibitively expensive. Thus, line protection is relative: some lightning strikes are allowed to hit the line and cause flashovers. This protection is primarily achieved using overhead ground wires.

In contrast, substations are far more critical. They serve as hubs of the power system, housing concentrated equipment and personnel. Consequently, their lightning protection requirements are extremely high.

Lightning can reach a substation via two main paths: direct strikes, mitigated by lightning rods (or sometimes shield wires); and surges propagating from lightning strikes on transmission lines, which are primarily handled by surge arresters.

Bayyana hadadawa a cikin motors (including generators, synchronous condensers, frequency changers, and electric motors) ce mafi muhimmanci kamar bayyana hadadawa a cikin substations. Generators ce "heart" of the power system, and large motors are vital industrial drivers. Lightning damage to these components results in significant losses. However, motor protection is more challenging than substation protection. Motors are rotating machines, so their insulation cannot be excessively thick and must be solid (unlike the liquid insulation used in transformers). Solid insulation is prone to aging, necessitating not only primary protection with surge arresters but also additional auxiliary protective measures.

Composite-Housed Zinc Oxide Surge Arresters

Surge arrester ce electrical device da duɗen electrodes - one typically grounded and the other connected to high voltage - separated by an insulating material, known professionally as an insulator.

Since most power system equipment is exposed to the atmosphere, the insulating surfaces are in direct contact with the environment. This portion of insulation is termed external insulation or outdoor insulation.

Outdoor insulation is constantly exposed to sunlight, rain, wind, snow, fog, and dew. Therefore, qualified outdoor insulation materials must not only possess excellent electrical and mechanical properties but also demonstrate superior weather resistance and a service life of 40-50 years. Currently, porcelain is the most widely used outdoor insulation material in engineering, with tempered glass also used in line applications.

Porcelain and glass are inorganic materials. Besides their excellent electrical and mechanical performance, their key advantage is environmental stability - exceptional resistance to climatic conditions - enabling them to dominate power system external insulation for nearly a century.

However, they share a common weakness: their surfaces are hydrophilic. This allows pollution layers on the insulator surface to absorb moisture. When pollution combines with moisture, it enables current flow, potentially causing a flashover across the insulator surface under normal operating voltage. This is commonly known as pollution flashover, more specifically, surface discharge along a polluted and wetted insulator.

In recent decades, silicone rubber has been widely adopted worldwide to replace traditional materials for insulators. Silicone rubber is an organic material exhibiting strong hydrophobicity, significantly increasing the pollution flashover voltage of external insulation.

Insulators made from organic materials are often called polymer insulators (as organic materials are polymers), non-ceramic insulators, composite insulators (since the external insulation is synthetic), or even plastic insulators abroad.

In China, they were previously known as composite insulators or silicone rubber insulators. They are now uniformly termed organic composite insulators (since organic materials are composites, and these insulators are typically made from a composite of silicone rubber and an epoxy-resin-glass-fiber rod), commonly abbreviated as composite insulators.

Therefore, a composite-housed zinc oxide surge arrester uses an organic material - specifically silicone rubber - as the external insulation for a zinc oxide surge arrester.