【關(guān)鍵詞】RCD；剩余電流保護(hù)器；路燈漏電；ASJ剩余電流繼電器

  0 引言

  幾天的河南省鄭州市特大暴雨持續(xù)牽動(dòng)著全國(guó)人民的心，相關(guān)新聞持續(xù)登上熱搜。其中2021年7月18日18時(shí)至21日0時(shí)，鄭州出現(xiàn)罕見(jiàn)持續(xù)強(qiáng)降水天氣過(guò)程，全市普降大暴雨、特大暴雨，累積平均降水量449毫米。7月21日3時(shí)，河南省防指決定將防汛應(yīng)急響應(yīng)別由Ⅱ提升為Ⅰ。7月21日，中共總書(shū)記、國(guó)家主席、軍委主席對(duì)防汛救災(zāi)工作作出重要指示。

  目鄭州已經(jīng)從暴雨災(zāi)害中初步走出，7月22日13時(shí)，鄭州市防指決定將防汛I應(yīng)急響應(yīng)降至Ⅲ，2021年7月24日10時(shí)，河南鄭州市區(qū)公交線(xiàn)路恢復(fù)營(yíng)運(yùn)率已達(dá)84%。

  本次暴雨損失慘重，截至2021年7月26日，據(jù)初步統(tǒng)計(jì)，暴雨引發(fā)的洪澇和次生災(zāi)害已導(dǎo)致69人遇難，930.57萬(wàn)人受災(zāi)。

  2021年7月24日起，年第六號(hào)臺(tái)風(fēng)“煙花”從江浙滬登陸，至27號(hào)基本結(jié)束對(duì)上海的影響，據(jù)統(tǒng)計(jì)“煙花”在近十年臺(tái)風(fēng)影響過(guò)程中雨量排名、風(fēng)速排名二（僅次于2019年第9號(hào)臺(tái)風(fēng)“利奇馬”），24日夜間到25日陸地和沿江沿海地區(qū)普遍出現(xiàn)9～12陣風(fēng)，洋山港區(qū)和沿海海面陣風(fēng)14。

  值得慶幸的是，由于上海提采取多項(xiàng)必要措施，包括部分地鐵公交停運(yùn)、工廠停工等，目未見(jiàn)到人員傷亡報(bào)道。但從全國(guó)范圍來(lái)看，本次臺(tái)風(fēng)并未結(jié)束，目繼續(xù)沿安徽山東北上，相關(guān)地區(qū)仍需做好各項(xiàng)預(yù)警措施。

  近幾年異常天氣增多，給全國(guó)人民的生命安全和財(cái)產(chǎn)安全帶來(lái)了巨大的危害，雖然在險(xiǎn)救災(zāi)中不斷涌現(xiàn)出可歌可泣的英雄事跡，但面對(duì)個(gè)個(gè)逝去的生命和巨大的經(jīng)濟(jì)損失，我們須反復(fù)思考，我們?cè)诎踩�預(yù)警和提防范方面還能做到哪些？

  實(shí)際上，災(zāi)害發(fā)生后的次生災(zāi)害往往危害更大，比如暴雨之后的路燈觸電事故。作為城市的基礎(chǔ)設(shè)施之，路燈運(yùn)行過(guò)程中，往往由于用電環(huán)境惡劣、線(xiàn)路老化、電纜接頭絕緣不良、整流器發(fā)熱、外力損壞、產(chǎn)品質(zhì)量等原因造成漏電，使路燈的金屬燈桿帶電，并直接危及到行人的安全。因此對(duì)路燈設(shè)施進(jìn)行采取防漏電措施勢(shì)在必行。

  剩余電流動(dòng)作保護(hù)器 ( Residual Current Operated Protective Devices，RCD) 是種漏電保護(hù)裝置，被廣泛地應(yīng)用在低壓配電系統(tǒng)中，是低壓電網(wǎng)防止電擊事故、電氣設(shè)備漏電損壞和電氣火災(zāi)的防護(hù)措施，在國(guó)內(nèi)外低壓電網(wǎng)中獲得了廣泛的應(yīng)用。

  1 路燈用電安全的現(xiàn)狀

  1）路燈設(shè)施被損壞情況較嚴(yán)重

  隨著城市的快速發(fā)展，道路改造、地鐵施工等市政建設(shè)越來(lái)越多，由于建設(shè)單位不規(guī)范、不文明施工造成電纜被挖斷、挖損的情況經(jīng)常發(fā)生，造成電纜裸露；此外，破壞路燈燈門(mén)造成燈線(xiàn)裸露、破損，都存在安全隱患。

  2）電纜接頭絕緣處理工藝落后

  路燈線(xiàn)路具有供電半徑長(zhǎng)、負(fù)載分散、接頭眾多的特點(diǎn)，而且接頭處理工藝多樣，無(wú)法做到標(biāo)準(zhǔn)化安裝。大部分地區(qū)采用傳統(tǒng)的膠布纏繞，部分地區(qū)采用絕緣穿刺、熱縮套管、灌封膠等，都存在不小的弊端，這種接頭容易進(jìn)水或混入水蒸氣，時(shí)間長(zhǎng)了就會(huì)逐漸損害電纜的絕緣強(qiáng)度而造成故障，運(yùn)行隱患很大。

  3）末端燈具的保護(hù)電器成為事故源之

  根據(jù)《城市道路照明工程施工及驗(yàn)收規(guī)程》（CJJ89-2012）的要求，每盞燈的相線(xiàn)應(yīng)裝設(shè)熔斷器作為燈具的保護(hù)電器，這種保護(hù)電器般沒(méi)有任何的防水防潮措施，固定或懸掛在燈桿檢修門(mén)內(nèi)，而燈桿內(nèi)屬高溫潮濕環(huán)境,其接線(xiàn)端子特別容易生銹,使得接觸電阻加大，通過(guò)電流時(shí)產(chǎn)生發(fā)熱從而燒毀接線(xiàn)端子燒斷燈線(xiàn)，“碰桿”現(xiàn)象時(shí)有發(fā)生。

  4）路燈電氣保護(hù)靈敏度不高

  目路燈配電采用TN-S系統(tǒng)，供電線(xiàn)路長(zhǎng)、阻抗大，再加上故障點(diǎn)接地電阻的影響，單相接地電流就比較小，路燈箱變內(nèi)線(xiàn)路多采用空氣開(kāi)關(guān)可能無(wú)法快速切除故障，出現(xiàn)漏電情況時(shí)不能及時(shí)、自動(dòng)切斷電源，容易出現(xiàn)燈桿或線(xiàn)路漏電情況。曾有設(shè)計(jì)院做過(guò)試驗(yàn)，900m（5*25）電纜末端發(fā)生火線(xiàn)碰桿，短路電流測(cè)得148A，端的63A塑殼開(kāi)關(guān)在42s后跳閘。

  5）城市內(nèi)澇成為普遍現(xiàn)象

  隨著城市化進(jìn)程的腳步，城市內(nèi)排水管網(wǎng)的建設(shè)跟不上城市面積的擴(kuò)大速度，到暴雨天氣，許多路段都會(huì)出現(xiàn)積水現(xiàn)象。路燈電纜的破損點(diǎn)、路燈電纜接頭、燈具的保護(hù)電器等如果發(fā)生浸水，其周?chē)�水域都可能�?huì)帶電。

  另外目燈桿燈門(mén)安裝高度般為離地40cm，但是由于建設(shè)時(shí)標(biāo)準(zhǔn)不或者道路改造造成后期路面升高等原因，燈門(mén)離地高度般達(dá)不到40cm，在暴雨等惡劣天氣下，會(huì)造成雨水倒灌燈桿內(nèi)，積水浸泡電纜接頭或積水處電纜破損導(dǎo)致周?chē)�水域和帶電，存在行人被跨步電壓擊倒的風(fēng)險(xiǎn)和安全隱患。

  因此，如何采取防漏電措施，防止人身觸電和由于漏電造成的種種危害，是目急需解決的問(wèn)題。

1 current situation of electric safety of street lamps

  1) the street lamp facilities are seriously damaged

  with the rapid development of the city, there are more ａnd more municipal construction such as road reconstruction ａnd subway construction. Cables are often cut ａnd damaged due to non-standard ａnd uncivilized construction by the construction unit, resulting in exposed cables; In addition, there are potential safety hazards by damaging the street lamp door, resulting in exposed ａnd damaged lamp lines.

   2) the insulation treatment process of cable joint is backward

   the street lamp line has the characteristics of long power supply radius, scattered load ａnd many joints, ａnd the joint treatment processes are diverse, so it is impossible to achieve standardized installation. Most areas use traditional tape winding, ａnd some areas use insulation puncture, heat shrinkable sleeve, potting glue, etc. there are many disadvantages. This kind of joint is easy to enter water or mix water vapor, which will gradually damage the insulation strength of the cable over a long time, resulting in failure ａnd great hidden dangers in operation.

   3) protective appliances of end lamps become one of the accident sources

   according to the requirements of code for construction ａnd acceptance of urban road lighting engineering (cjj89-2012), the phase line of each lamp shall be equipped with a fuse as the protective appliance of the lamp. Generally, this protective appliance is fixed or hung in the lamp post access door without any waterproof ａnd moisture-proof measures. However, the lamp post is in a high-temperature ａnd humid environment, ａnd its wiring terminal is particularly easy to rust, resulting in increased contact resistance, When the current passes through, it generates heat, thus burning the wiring terminal, burning the lamp line, ａnd the phenomenon of "hitting the rod" occurs from time to time.

   4) the electrical protection sensitivity of street lamps is not high

   at present, TN-S system is adopted for street lamp distribution, with long power supply line ａnd large impedance. In addition, due to the influence of grounding resistance at fault point, the single-phase grounding current is relatively small. Air switches are mostly used in the lines in street lamp box transformer, which may not be able to quickly remove the fault. In case of leakage, the power supply cannot be cut off timely ａnd automatically, which is prone to leakage of lamp pole or line. A design institute has conducted a test. The live wire bumped the pole at the end of 900m (5 * 25) cable, the short-circuit current was measured as 148A, ａnd the 63A plastic shell switch at the front tripped after 42s.

  5) urban waterlogging has become a common phenomenon

  with the pace of urbanization, the construction of urban drainage network can not keep up with the expansion of urban area. When it comes to rainstorm weather, ponding will occur in many road sections. If the damage point of street lamp cable, street lamp cable joint ａnd protective appliances of lamps are flooded, the surrounding waters may be charged.

   in addition, at present, the installation height of the lamp door of the lamp pole is generally 40cm above the ground. However, due to different standards during construction or the rise of the road in the later stage caused by road reconstruction, the height of the lamp door from the ground is generally less than 40cm. In severe weather such as rainstorm, rain will pour back into the lamp pole, the ponding will soak the cable joint or the cable at the ponding will be damaged, resulting in the surrounding water area ａnd electrification, There is a risk ａnd potential safety hazard that pedestrians are knocked down by step voltage.

Therefore, how to take anti electric leakage measures to prevent personal electric shock ａnd various hazards caused by electric leakage is an urgent problem to be solved.

  2 相關(guān)國(guó)家標(biāo)準(zhǔn)的規(guī)定

  1）《GB 50054-2011 低壓配電設(shè)計(jì)規(guī)范》第5.2.18 規(guī)定：

  “TT系統(tǒng)中，配電線(xiàn)路的間接接觸防護(hù)的保護(hù)電器應(yīng)采用剩余電流動(dòng)作保護(hù)電器或過(guò)電流保護(hù)電器。”

  第5.2.13規(guī)定：

  “TN系統(tǒng)中，配電線(xiàn)路采用過(guò)電流保護(hù)電器兼作間接接地防護(hù)電器時(shí)，其動(dòng)作特性應(yīng)符合本規(guī)范第5.2.8條的規(guī)定；當(dāng)不符合規(guī)定時(shí)，應(yīng)采用剩余電流動(dòng)作保護(hù)電器。”

  可見(jiàn)采用TT接地方式的路燈配電線(xiàn)路和過(guò)流保護(hù)無(wú)法滿(mǎn)足保護(hù)要求的TN接地方式的路燈配電線(xiàn)路都應(yīng)配置剩余電流動(dòng)作保護(hù)電器作為保護(hù)措施。

  2）《CJJ 45-2015 城市道路照明設(shè)計(jì)標(biāo)準(zhǔn)》第6.1.5條規(guī)定：

  “道路照明配電系統(tǒng)應(yīng)具有短路保護(hù)和過(guò)負(fù)荷保護(hù),并應(yīng)符合國(guó)家標(biāo)準(zhǔn)GB50054《低壓配電設(shè)計(jì)規(guī)范》的要求,各單相回路應(yīng)單獨(dú)進(jìn)行控制和保護(hù)。每個(gè)燈具應(yīng)設(shè)有單獨(dú)保護(hù)裝置。”

  3）《GBT 13955-2017 剩余電流動(dòng)作保護(hù)裝置安裝和運(yùn)行》

  其中第4.4條 “應(yīng)安裝RCD的設(shè)備和場(chǎng)所”中的4.4.1 d類(lèi)“安裝在戶(hù)外的電氣裝置”，路燈作為室外的用電設(shè)備，應(yīng)該配備剩余電流動(dòng)作保護(hù)裝置。

  3 ASJ系列剩余電流繼電器

  安科瑞電氣提供的ASJ系列剩余電流動(dòng)作繼電器可與低壓斷路器或低壓接觸器等組成組合式剩余電流保護(hù)裝置，適用于交流 50Hz，額定電壓 400V 及以下的 TT 和 TN 系統(tǒng)配電線(xiàn)路，用來(lái)對(duì)電氣線(xiàn)路進(jìn)行接地故障保護(hù)，防止接地故障電流引起的設(shè)備損壞和電氣火災(zāi)事故，也可用來(lái)對(duì)人身觸電危險(xiǎn)提供間接接觸保護(hù)。

  1）型號(hào)和功能

  2）技術(shù)參數(shù)

  3）典型應(yīng)用示意圖

  4 小結(jié)

  保證路燈設(shè)施安全運(yùn)行是路燈管理部門(mén)的重要工作，但光靠到處巡查是不足以解決問(wèn)題的，通過(guò)對(duì)低洼易澇點(diǎn)配電線(xiàn)路安裝RCD類(lèi)裝置，同時(shí)輔以人工巡查和其它措施，比如要求道路改造施工單位合乎規(guī)范、文明施工等，做到科技手段與日常管理相結(jié)合，才能大限度地減少觸電傷亡事故的發(fā)生。