Uchanganuzi wa Sababu Zinazofanana za Kutokwa na Pungufu ya Gazi katika SF6 Circuit Breakers za Substations na Utafiti kuhusu Hatua za Kudhibiti
Kwa maendeleo ya teknolojia na uzalishaji wa kiwango kikubwa, ufanisi na ubora wa vifaa vya kupungua mizigo SF₆ vilivyotumiwa kwa kutumia umeme uliyofanikiwa kuongezeka, na bidhaa zimepata utambulisho wazi kutoka kwa wateja. Hata hivyo, kwa kutumika kwa uraibu, idadi ya hitimisho imeongezeka pia. Sababu za hitimisho ni kama vile msingi wa udhibiti, mifano ya kutengeneza, na chaguo la vitu vinavyotumiwa. Kwa kutafuta na kukusanya taarifa za sababu za hitimisho, inajulikana kuwa 20%-30% ya matatizo yanayotokana na ukosefu wa hishimiwa wa SF₆. Kutafuta ukosefu wa hishimiwa ni muhimu sana na haiwezi kupunguliwa katika hatua za kutengeneza umeme.
1 Sababu Makuu
Ukosefu ni tabia ya kawaida. Matatizo ya ukosefu yanaweza kutokea popote ambapo kuna tofauti za ongezeko, joto, na nguvu. Tume muhimu ya kisayansi inapaswa kutumika kwa ajili ya tofauti za ukosefu, na changamoto ya ukosefu inapaswa kutafutwa mara moja.
1.1 Ukosefu wa Nje wa Mikono ya Hisani
Kwa mikono yoyote ya hisani, mahali na maelezo ya ukosefu wanaweza kutokea tofauti. Mara nyingi, mahali ya kawaida ya ukosefu ni:
Vito, nyuzi, na gasket. Vitengo vyenye mita tatu, vito vya kutoa mafuta, vito vya kwanza, vito vya pili, vito vya usalama, na vyenyingine. Sababu za ukosefu ni kama vile upimaji wa kitu cha vito si sahihi, uwiano wa eneo la majukumu haupungukiwi vizuri kutokana na ukurasa wenye kutengeneza; viwanda vya mchakato, eneo linalopunguka, na bauti za kuleta hasira zinazokuwa zenye ukosefu.
Mazingira ya kuunganisha maneno na vifaa vya elektromekaniki. Nyuzi za mazingira haya zinaweza kuwa isiyozingatika au zinaweza kupoteza nguvu zao, ambayo inaweza kuwa sababu ya ukosefu.
Eneo la majukumu la pistoni la mifuko ya kutumia na pistoni la mifuko ya kuhifadhi iliyotolewa na mtengenezaji. Kwa sababu ya nyuzi na gasket katika eneo hili huenda kuwa na mwendo wa mgando, ni rahisi kwa sana kuchanganyikiwa, kudumu, au kuharibiwa.
Matokeo ya ukosefu wa mikono ya hisani ni vigumu sana. Ukosefu mdogo tu unaweza kusababisha utaratibu wa mifuko ya mafuta na muda mrefu wa kupunguza nguvu. Ukosefu wa mafuta mkubwa katika mifuko ya mafuta itasababisha tatizo la kupunguza nguvu. Waktu mafuta ya hisani yakija katika mifuko ya kuhifadhi, nguvu katika eneo la hasira litakuwa linongeza mara kwa mara, kusababisha hutuma ya dharura, kutumia vibaya, na matatizo ya vifaa, ambayo itapiga kibara kwa usalama wa kutumia vifaa.
1.2 Ukosefu wa Nje wa Jicho la Kuu na Uunganisho
Vyama. Kwa sababu ya nguvu kali katika vyama, vyama vinaweza kuvunjika, kusababisha ukosefu mdogo. Baada ya muda fulani, idadi ya ukosefu itakuwa inongezeka mara kwa mara. Katika mahali pa vyama vya aina mbili, kwa sababu ya nguvu kubwa, vinyama vya vyama vinaweza kusababisha ukosefu. Kwa kutumia teknolojia ya kutengeneza ya mtengenezaji, uwezekano wa tabia hii kukurudi wakati wa kutengeneza na kutumia vifaa ni ndogo.
Mahali pa kuunganisha chupa ya porselein na flange. Kwa sababu ya nguvu kubwa katika eneo hili, ukosefu unaweza kutokea ikiwa punguza si sahihi, kama vile kutengeneza chapa ya chupa ya porselein isiyozingatika, eneo lisilo sawa, na nyuzi zinazopunguka si sahihi au hazitoshi.
Mazingira ya pipa, mazingira ya vifaa vya kupunguza umbali, misingi ya vito, mfuniko wa sanduku la mita tatu, na mahali mengine. Mahali haya ni machache kwa kuunganisha, kupunguza, na vyama, na ni mahali magumu na madogo ya kupunguza, na uwezekano wa ukosefu ni mkubwa.
Kwa hasira ya SF₆, eneo la majukumu katika eneo lolote linapaswa kuwa safi sana. Vinginevyo, hata kijiji kidogo cha vitu visivyo ya anuwai katika eneo la majukumu linaweza kuboresha kiwango cha ukosefu hadi kiwango cha 0.001MPa.M1/s, ambacho halipaswi kuonekana kwenye vifaa. Kwa hiyo, kabla ya kutengeneza, eneo la majukumu na gasket lazima lipepetwe vizuri kwa kutumia rangi nyeupe na karatasi nzuri ya choo iliyotengenezwa na kioo, na utafiti mzuri unaufanyika. Utengenezi unaweza kufanyika baada ya kutambua kwamba hakuna shida. Pia, ununuzi wa mchanga katika flange, viwanda vya bauti, na bauti lazima lipetwe ili kuzuia kutokana na kuingia kwenye eneo la majukumu, hasa wakati wa kutengeneza majukumu ya kusinzia.
2 Njia za Kutafuta Ukosefu wa SF₆ Circuit Breaker
2.1 Njia ya Ukuaji wa Msimbo wa Maji
Msingi mkuu ni kwamba kwa maji yenye nguvu kubwa ya ukosefu kama maji ya sabuni, vifungo vinaweza kuonekana katika mahali pa ukosefu wakati hasira inakosefika. Njia ya kutafuta ni kutumia maji ya sabuni na vitu vingine kwenye ngome ya SF₆ circuit breaker na mahali ambapo ukosefu unaweza kutokana.
Maoni yasiyozuri: Maagizo yasiyozuri kwa kutumia, haiwezi kutafuta ukosefu mdogo, na baadhi ya mahali haipaswi kutumika.
Maoni yasiyozuri: Inaonekana vizuri.
2.2 Kutafuta Ukosefu wa Kiutamaduni
Msingi mkuu ni kwamba SF₆ ana nguvu kubwa ya elektronegativity. Kwa athari ya high voltage ya pulsed, mchakato wa discharge wa kutosha unafanyika, na hasira ya SF₆ itabadilisha uwezo wa corona electric field, kwa hiyo kutafuta upatikanaji wa SF₆ gas on-site. Hii ni tu kutekeleza kiwango cha ukosefu cha vifaa vya SF₆ circuit breaker, si kutafuta kiwango chake cha ukosefu. Kutafuta ukosefu wa kiutamaduni inajumuisha njia ifuatayo:
Utambuzi wa vacuum pumping. Pump the vacuum to 133Pa, endelea kupumpa zaidi ya dakika 30, stop the pump, read the value A after observing for 30 minutes, and then read the value B after observing for 5 hours. If 67Pa > B - A, it can be determined that the sealing is good.
Foaming liquid detection. This is a relatively simple qualitative leakage method that can accurately find the leakage point. The foaming liquid can be prepared by adding a neutral soap to two parts of water. Apply the foaming liquid to the position to be detected for leakage. If bubbles appear, it indicates leakage at this position. The more and more urgent the bubbles are, the more serious the leakage is. This method can roughly find the leakage position with a leakage rate of 0.1ml/min.
Leakage detector detection. The leakage detector detection is to move the probe of the leakage detector along the surface of each connection of the circuit breaker and the surface of the aluminum casting, and determine the leakage situation according to the reading of the leakage detector . When using this method, the following techniques should be mastered: First, the movement speed of the probe should be slow to prevent missing the leakage due to too fast movement. Second, the detection should not be carried out in a strong wind to prevent the leakage from being blown away and affecting the detection. Third, a leakage detector with high sensitivity and low response speed should be selected. Generally, the minimum detectable amount of the leakage detector is that the leakage rate is lower than 10-6, and the response speed is lower than 5s, which is more appropriate.
Segmentation and positioning method. This method is suitable for circuit breakers with three-phase SF₆ gas circuit connections. If leakage is determined but it is difficult to locate, the SF₆ gas structure can be divided into several parts for detection, thereby reducing blindness.
Pressure reduction method. This method is applicable when the leakage amount of the equipment is large.
2.3 Quantitative Leakage Detection
This is to detect the leakage rate of the SF₆ circuit breaker, and the judgment standard is that the annual leakage rate does not exceed 1%. The specific methods are as follows: (1) Local Wrapping Method: Use a plastic film with a thickness of 0.01 cm to wrap around the geometric shape of the density position for one and a half circles, with the joint facing upwards. Try to form a circular or square shape, and seal it with adhesive tape after shaping [3]. There should be a certain gap, approximately 0.05 cm, between the plastic film and the object being measured. After wrapping, detect the content of SF₆ gas in the wrapped cavity after 24 hours, and select the average value of four points at different positions. The leakage rate of this sealing process can be calculated using the following formula:F=ΔC⋅(V−ΔV)⋅P/Δt(MPa⋅m3/s)
Where:
The annual leakage rate Fy of each gas chamber is calculated as follows: Fy=F⋅31.5×10−6/V⋅(Pr+0.1)⋅100% (per year) Where Pr is the specified SF₆ gas pressure (MPa).
When starting the above calculations, the following parameters are difficult to determine:
Hanging Bottle Detection Method: Hang a bottle at the detection hole of the insulator. After a few hours, use a leakage detector to detect whether there is leaked SF₆ gas in the bottle.
2.4 Infrared Detection
The infrared detection method mainly uses the strong infrared absorption property of SF₆ gas. SF₆ gas has the strongest absorption of infrared rays with a wavelength of 10.6um. Common infrared detection methods include the infrared laser method and the passive detection method.
The working principle of laser infrared detection is that an incident infrared laser is transmitted by the laser transmitter, and the backscattered laser enters the laser camera imaging platform through reflection. If the incident laser encounters leaked SF₆ gas, some of its energy will be absorbed, resulting in differences in the backscattered laser in the case of leakage and no leakage, and finally, different laser imaging can be used to detect the presence of SF₆ gas leakage. The passive detection method does not actively transmit laser light but detects the slight differences caused by the absorption of infrared rays in the atmosphere by SF₆ gas to detect the presence of SF₆ gas.
The refrigeration quantum well detector selected for foreign scientific products can determine a temperature difference of 0.03°C, and the minimum detectable gas volume is 0.001ml/s of SF₆ gas. Both of the above methods use an imaging viewfinder to display the image, making the invisible SF₆ gas visible. On the viewfinder display, the leaked SF₆ gas can be seen as a dynamic black cloud, which is clearly visible in a static environment. By carefully observing the position where the cloud emerges, the leakage source can be quickly and accurately located. The speed and size of the cloud reflect the leakage rate.
The infrared detection method of SF₆ gas can remotely detect the leakage position without power outage, ensuring personal safety and improving the stability of power supply. It is the most scientific detection method at present.
Strengthening the prevention of SF₆ circuit breaker leakage is a key supervision point to ensure the safe, economical, and reliable operation of substations. By analyzing the causes of SF₆ circuit breaker leakage, the theoretical level of preventing and dealing with SF₆ circuit breaker leakage problems can be continuously improved, and the ability to deal with SF₆ leakage accidents can be enhanced. Among various detection methods, infrared imaging detection is a new technical method for the condition-based maintenance of SF₆ circuit breakers and is the mainstream development trend in the future.
