陰極保護(hù)設(shè)計基本要求 Basic requirements for cathodic protection design

時間：2022-09-09作者：焦作市虹泰防腐材料有限公司瀏覽：83

陰極保護(hù)設(shè)計基本要求

(1)電連續(xù)性：被保護(hù)結(jié)構(gòu)必須電氣導(dǎo)通。焊接管道沒有電連續(xù)問題，但對于承插口連接的管道，管段之間要進(jìn)行跨接。

(2)電氣絕緣：被保護(hù)結(jié)構(gòu)必須與其他埋地設(shè)施或接地系統(tǒng)電絕緣。絕緣接頭盡量地上安裝。設(shè)置管道絕緣位置時，要充分認(rèn)識到以下兩點(diǎn):

①陰極保護(hù)電流可能會引起絕緣接頭非保護(hù)側(cè)腐蝕。管道內(nèi)部有積液時，絕緣接頭要安裝在高處或豎直安裝，避免內(nèi)部積液。

②有絕緣就要有防雷保護(hù)。例如閥室內(nèi)部接地網(wǎng)通常與主閥隔離，如果對電氣隔離不進(jìn)行保護(hù)，往往會導(dǎo)致絕緣墊或絕緣卡箍被擊穿。

(3)站場接地：工藝管道可以通過避雷器與接地網(wǎng)連接。同部接地較可以使用鍵鋅材料，但有可能影響陰極保護(hù)系統(tǒng)工作。

(4)電屏蔽：聚乙烯膠帶防腐層、熱縮套及泡沫保溫層可能會導(dǎo)致陰極保護(hù)無效。

(5)混凝土加重層：沼澤、水網(wǎng)地帶的管道混凝土加重層要避免鋼筋與管道接觸。

(6)鋼套管穿越：避免主、套管短路，套管有高質(zhì)量涂層時,兩端預(yù)留一段裸管。

(7)交流排流：**利用站場、閥室接地較以及穿路鋼套管進(jìn)行排流，排流不夠時，安裝額外接地較，接地較與管道之間安裝通交隔直裝置。

（8）并行管道:避免管道與地床之間的干擾或管道之間的屏蔽問題，必要時聯(lián)合保護(hù)(涂層差異大時難以實(shí)現(xiàn))。當(dāng)無法避免陽極地床對相鄰管道的陽極干擾時，要加強(qiáng)受干擾管道的防腐層。

（9）如果定向鉆穿越段管道防腐層損壞嚴(yán)重，盡量不要采取回拖再鉆的方式?？梢酝ㄟ^加強(qiáng)局部陰極保護(hù)，如埋設(shè)犧牲陽極或增加陰極保護(hù)站的方式保護(hù)穿越段管道。

Basic requirements for cathodic protection design
1.  Electrical continuity: the protected structure must be electrically conductive. There is no electrical continuity problem for welded pipes, but for pipes connected by sockets, the pipe sections should be bridged.
2.  Electrical insulation: the protected structure must be electrically insulated from other buried facilities or grounding systems. Insulated joints shall be installed on the ground as far as possible. When setting the pipeline insulation position, the following two points shall be fully recognized:
（1） Cathodic protection current may cause corrosion on the unprotected side of insulated joints. When there is liquid accumulation inside the pipeline, the insulation joint shall be installed at a high place or vertically to avoid liquid accumulation inside.
（2） If there is insulation, there must be lightning protection. For example, the grounding grid inside the valve chamber is usually isolated from the main valve. If the electrical isolation is not protected, the insulation pad or insulation clamp will be broken down.
（3） Station grounding: the process pipeline can be connected to the grounding grid through lightning arrester. The bonding zinc material can be used for the same grounding electrode, but it may affect the operation of the cathodic protection system.
（4） Electric shielding: polyethylene tape anticorrosive coating, heat shrinkable sleeve and foam insulation layer may lead to ineffective cathodic protection.
（5） Concrete weighting layer: the pipeline concrete weighting layer in swamp and water network areas shall avoid the contact between reinforcement and pipeline.
（6） Steel casing crossing: to avoid short circuit between main casing and casing. When the casing has high-quality coating, a section of bare pipe shall be reserved at both ends.
（7） AC drainage: the grounding electrode of the station and valve chamber and the steel sleeve through the pipeline shall be used for drainage preferentially. If the drainage is not enough, an additional grounding electrode shall be installed, and a communication and straight separation device shall be installed between the grounding electrode and the pipeline.
（8） Parallel pipeline: avoid interference between pipeline and ground bed or shielding between pipelines, and conduct joint protection when necessary (difficult to achieve when coating difference is large). When it is impossible to avoid the anode interference of the anode ground bed to the adjacent pipeline, the anti-corrosion coating of the disturbed pipeline shall be strengthened.
（9） If the anti-corrosion coating of the pipeline at the crossing section of directional drilling is seriously damaged, try not to drag back and drill again. Local cathodic protection can be strengthened, such as burying sacrificial anodes or adding cathodic protection stations to protect the crossing pipeline.




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• 詞條

  詞條說明

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  判斷陰極保護(hù)是欠保護(hù)還是過保護(hù)，判斷指標(biāo)是管道的斷電電位，不能以通電電位來判斷，因?yàn)橥婋娢恢泻蠭R降。陰極保護(hù)電源(如恒電位儀)顯示的是通電電位，只要斷電電位不**標(biāo)，通電電位多大都沒關(guān)系。盡管實(shí)驗(yàn)室的實(shí)驗(yàn)證明了氫致開裂現(xiàn)象，但工程實(shí)踐中幾乎沒有發(fā)現(xiàn)氫致開裂的案例。因此，對于氫致開裂沒必要過度擔(dān)心，尤其是X80以下的鋼制管道，不需要考慮氫致開裂問題。工程上常見的3LPE防腐層剝離現(xiàn)象,是由于工廠

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