Anailís ar Chúrsaí Coitianta Leacaimh Gáise i Bhreicfidil SF6 Stáisiún Ionaid agus Taighde ar Mheastacháin Dianachta

Mar éiríonn le teicneolaíocht agus feabhsaíonn na meáin chumhachta, tá an fheidhmíocht agus an cáilíocht den tionscal SF₆ circuit breaker ar fás leanúnach, agus tá an tionscal seo aitheanta go forleathan ag custaiméirí. In ainneoin sin, mar gheall ar a úsáid laethúil, tá an tréimhse ina bhfuil deifecte ann tar éis dul chun cinn. I measc na gcúrsaí atá freagrach as na deifecte, tá rudaí cosúil le príomhaidiacht an dhuine, próisis déantúsa, agus roghnú ábhair. Trí staidéar a dhéanamh ar na cúrsaí atá freagrach as na deifecte, is eol dúinn gur 20%-30% den fhadhb atá bunaithe ar fuacailt SF₆ gas. Tá diancháin SF₆ gas ceann de na pointí is tábhachtaí agus gan é a dhéanamh amach sa stád umsholais.

1 Príomhchúrsaí

Is cosúil go forleathan le fuacailt. Mar gheall ar aon difríocht i n-aonrú, teocht, agus brú, is féidir le fuacailt tarlú. Ba chóir modhanna eolaíochta a úsáid do chúrsaí fuacailte éagsúla, agus ba chóir an foinsí fuacailte a aimsiú go héifeachtach.

1.1 Fuacailt Eile Máchine Hydraulach

Do mháithreacha hydraulacha éagsúla, is féidir leis an suíomh agus an chás fuacailte a bheith éagsúil. Go hiondúil, is iad na suíomhanna fuacailte is coitianta:

• Válv, sealadh, agus gasket. Triúir válv, válv siúil, válv príomha, válv dara, válv cosanta, srl. Is féidir le fuacailt tarlú mar gheall ar díchúram i mbarr an válv, comharra contae neamhionrach; buille san córas válv, suíomh gan sealadh, agus boltaí scuabadh gaistí neamhdhlíthiúla.

• An suíomh comhcheangailte idir mheasaróir brú agus uirlisí electromechanical. D'fhéadfadh na gasket sealacha seo a bheith neamhionrach nó a bhaint as a ndínimh, rud a d'fhéadfadh fuacailt a chur ar siúl.

• An t-suíomh sealadh ag pistón cilindr operáide agus pistón cilindr stórála a sholáthraíonn an t-ionadaí. Óirfiú go bhfuil na gasket agus sealadh sa suíomh seo faoi thiomáint mórfhricce, is dócha gur féidir leo athrú, luirg, nó damáiste a fháil.

Tá na torruithe fuacailte máchine hydraulach an-dian. Ní hamháin go d'éiríonn fuacailt beag leis an nglanadh, ach cuireann sé isteach ar an bpumpa óil a dhéanamh arís agus arís, agus cuireann sé isteach ar an gcúrsa brú a leas. Mura ndéantar fuacailt mór óil sa válv, d'fhéadfadh sé dífhostas brú a chur ar siúl. Nuair a théann an t-ól hydraulach isteach sa chilindr stórála, fósfaidh an brú ar an taobh gaistí, rud a d'fhéadfadh deifecte, míchleachtadh, agus mídhleachtadh a chur ar siúl, ag cur isteach ar an oibriú slán.

1.2 Fuacailt Eile ag an gCorpus agus Comhcheangal

•  Lasadh. Mar gheall ar an gcomhshaoil mór le linn an lasadh, is féidir leis an gcorpus lasadh a bheith trína chéile, rud a d'fhéadfadh fuacailt bheag a chur ar siúl. Tar éis tréimhse, d'fhéadfadh an méid fuacailte a chur ar siúl go leanúnach. Ag an suíomh lasadh dá mhéid ábhar éagsúla, d'fhéadfadh lasadh a bheith trína chéile mar gheall ar an mbhrú áitiúil ard, ag cur isteach ar an fuacailt. Le feabhas a dhéanamh ar an dtionscal déantúsa, is íseal an t-éileamh air seo nuair a bheidh sé suite agus ag obair.

• An suíomh comhcheangailte idir an t-súgradh porcíne agus an flange. Mar gheall ar an brú ard sa suíomh seo, is féidir le fuacailt tarlú más éard nach bhfuil an sealadh cruinn, mar shampla, an gné comhcheangailte den t-súgradh porcíne neamhionrach, an tsuíomh comhcheangailte neamhionrach, agus an gasket sealadh neamhdhlíthiúil.

• Comhcheangailte pípe, comhcheangailte uirlisí densiti, deirid an mheasaróir brú, capa triúir box, agus suíomh eile. Is iad seo na suíomhanna is coitianta chun comhcheangailte, sealadh, agus lasadh a dhéanamh, agus is iad na suíomhanna is deacra agus is láidre chun sealadh a dhéanamh, agus is íseal an t-éileamh air seo.

Do SF₆ gas, caithfidh gach suíomh sealadh a bheith glan go leor. Más amhlaidh, fiú mura bhfuil aon rud éigríochta bheag ag an suíomh sealadh, is féidir leis an rát fuacailte a chur ar siúl go 0.001MPa.M1/s, rud nach féidir leis an tionscal. Mar sin, roimh an suite, caithfidh an suíomh sealadh agus an gasket a shábháil go cruinn le clúid bán agus páipéar toilite de cheann de chuid deoch, agus tuarascáil mionsonraithe a dhéanamh. Is féidir leis an suite a dhéanamh amháin tar éis a chinntiú gur éisteacht leis. Chomh maith leis sin, caithfidh an dust ar an flange, boltaí, agus comhcheangailte a shábháil chun é a chosaint ó dhlíthiúlacht, go háirithe ag an am suite sealadh ingear.

2 Modhanna Diancháin SF₆ Circuit Breaker
2.1 Modh Tension Uisceach

Is é an príomhphrionsabal ná gur féidir le uisceach le tension láidir cosúil le sabúin, bubbláin a thárlú ag an suíomh fuacailte nuair a fuacaíonn gas. Is é an modh diancháin a chur ar siúl sabúin agus rudaí eile a chur ar an gcorp SF₆ circuit breaker agus ar an suíomh fuacailte éagsúla.
Miontuairisc: Meastar go forleathan le smearing, ní féidir leis fuacailt bheag a aimsiú, agus ní féidir le cuid de na suíomhanna a smearadh.
Buntáiste: Intuitive.

2.2 Diancháin Cáiliúil

Is é an príomhphrionsabal ná go bhfuil SF₆ leathnachadh ionchais láidir. Faoin tionchar brú high voltage pulse, tarlann efíocht a leanúint, agus beidh SF₆ gas ag athrú an corona electric field, ag cur isteach ar an láthair SF₆ gas. Is é seo a dhéanamh ach chun an ráta fuacailte SF₆ circuit breaker tionscal a aimsiú, seachas a dhéanamh a dhiancháin a dhéanamh. Is iad seo na modhanna diancháin cáiliúil:

• Diancháin vacuum. Pump the vacuum to 133Pa, keep pumping for more than 30 minutes, 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 Diancháin Cinnte

Is é seo a dhéanamh a dhiancháin ar an ráta fuacailte SF₆ circuit breaker, agus an crioch a aimsiú ná nach raibh an ráta fuacailte bliantúil os cionn 1%. Is iad na modhanna speisialta seo: (1) Modh Lúbáil Áitiúil: Úsáid film plastic le 0.01 cm airde chun an géarú den suíomh density a lúbáil ar feadh haon agus leath chiorcail, leis an gcomhcheangal suas. Ardaigh form aerach nó cearnach, agus sealadh le tapa adheseach tar éis an fhoirm a dhéanamh [3]. Ba chóir go mbeadh spás beag, thart ar 0.05 cm, idir an film plastic agus an rud a mheastar. Tar éis an lúbáil, diancháin ar an ábhar SF₆ gas sa lúbáil tar éis 24 uair an chloig, agus roghnaigh an luach meánach de cheithre phointe ar suíomh éagsúla. Is féidir an ráta fuacailte den sealadh seo a réiteach leis an fórmhór:F=ΔC⋅(V−ΔV)⋅P/Δt(MPa⋅m3/s)

 Áit:

• F: Absolute leakage rate, leakage amount per unit time (MPa⋅m³/s).

• Δ C: Average value of the detected leakage content (ppm).

• ΔV: Volume between the object being measured and the plastic film (m³).

• Δt: Time interval for detecting ΔC(s).

• P: Absolute atmospheric pressure, which is 0.1MPa.

• V: Volume of SF₆ gas in the gas chamber (m³).

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:

• Δ V: Since the volume between the object being measured and the plastic film has an irregular shape, its volume cannot be directly calculated. Experimental methods can be adopted, such as injecting other gases and liquids through a flowmeter into the wrapped cavity to collect volume information.

• V and W: The gas volume and mass of SF₆ in the gas chamber. This information is not provided by the manufacturer. You can require the manufacturer to provide accurate information in the order technical documents, or use a metering method during gas filling to obtain more precise information.

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.