1.溫度高造成配電箱電氣裝備使用壽命降落

1. High temperature causes a decrease in the service life of electrical equipment in distribution boxes

按國標(biāo)設(shè)計和制造的電氣裝備運行時周圍環(huán)境溫度的上限值不應(yīng)超過40℃，而夏天暴露在烈日中的運行配電箱，因為太陽光的直射、水泥地面熱量的 反射和箱內(nèi)裝備本身發(fā)生的熱量，有時箱內(nèi)的溫度竟超過60℃。如此高的溫度極易造成電器線圈、引線的絕緣老化而擊穿燒壞；電器觸頭因溫度太高而增添接觸電 阻，接觸電阻增添又加重發(fā)燒，如此惡性循環(huán)終究導(dǎo)致觸頭燒壞；同時溫度太高還會影響電器保護機能的穩(wěn)定性、動作的可靠性、計量的準(zhǔn)確性。

The upper limit of the ambient temperature during the operation of electrical equipment designed and manufactured according to national standards should not exceed 40 ℃. However, for operating distribution boxes exposed to scorching sun in summer, due to direct sunlight, reflection of heat from cement floors, and heat generated by the equipment inside the box, sometimes the temperature inside the box exceeds 60 ℃. Such high temperatures can easily cause insulation aging of electrical coils and leads, leading to breakdown and burnout; Electrical contacts increase contact resistance due to high temperatures, which in turn exacerbates fever. This vicious cycle ultimately leads to contact burnout; At the same time, high temperatures can also affect the stability of electrical protection functions, the reliability of actions, and the accuracy of measurements.

2.只在進線側(cè)裝設(shè)避雷器，防雷保護不能籠蓋全裝備

2. Install lightning arresters only on the incoming side, and lightning protection cannot cover the entire equipment

通常配電箱的進出線與其母線間都裝有熔斷器等裝備，出線受到雷擊時，如造成進線熔斷器先行熔斷，此時全部配電箱將失去防雷保護，每一年都有許多配電箱因遭雷擊而破壞。

Usually, fuses and other equipment are installed between the incoming and outgoing lines of distribution boxes and their busbars. When the outgoing lines are struck by lightning, if the incoming fuse is blown first, all distribution boxes will lose lightning protection. Every year, many distribution boxes are damaged due to lightning strikes.

3.安裝工藝不當(dāng)，引發(fā)連接頭過熱燒損

3. Improper installation process may cause overheating and burning of the connection head

有的電工在改換引線時不壓接線鼻，用多絞線繞制線鼻螺接，結(jié)果換線后不久又造成引線燒斷。有的廠家出產(chǎn)的配電箱，分線堆疊螺接在總線上，散熱不好，負荷一重自然構(gòu)成故障不斷。

Some electricians do not compress the wire nose when changing the lead, and use multiple twisted wires to wind the wire nose and screw it together, resulting in the lead burning out shortly after the wire change. Some manufacturers produce distribution boxes with branch lines stacked and threaded on the bus, which have poor heat dissipation and a heavy load, naturally causing continuous faults.

4.配電箱不經(jīng)檢查即投入使用，給留下隱患

4. The distribution box is put into use without inspection, leaving a hidden danger to safety

雖然裝備制造商提供的產(chǎn)品在出廠時都作過嚴(yán)格的檢驗，但因為路途顛簸及裝卸振動，運達現(xiàn)場后部份連接螺栓可能會呈現(xiàn)一定程度的松動，導(dǎo)致一些配電箱投運后不久就呈現(xiàn)了引線接頭過熱現(xiàn)象。

Although the products provided by equipment manufacturers have undergone strict inspections before leaving the factory, due to road bumps and loading and unloading vibrations, some connecting bolts may become loose after arriving at the site, resulting in overheating of some distribution boxes shortly after they are put into operation.

5.配電箱安裝位置不恰當(dāng)，不但影響市容市貌，還易受外力損害。建議綜合斟酌選擇適量的安裝位置。

5. Improper installation of distribution boxes not only affects the appearance of the city, but also makes them susceptible to external damage. It is recommended to carefully consider selecting an appropriate installation location.

6.有的保護接零的供電系統(tǒng)仍采用三相四線制供電方式，低壓電網(wǎng)的零線較長、阻抗較大，當(dāng)三相負荷不平衡時零線將有零序電流通過，同時因為環(huán)境惡化、導(dǎo)線老化、受潮等因素，導(dǎo)線的漏電流通過零線也構(gòu)成閉合回路，導(dǎo)致零線帶有一定的電位，這對于運行十分不利。

6. Some power supply systems that protect the neutral connection still adopt a three-phase four wire power supply method. The neutral line of the low-voltage power grid is long and has a high impedance. When the three-phase load is unbalanced, the neutral line will have zero sequence current passing through. At the same time, due to environmental degradation, wire aging, moisture and other factors, the leakage current of the wire passing through the neutral line also forms a closed circuit, causing the neutral line to have a certain potential, which is very unfavorable for safe operation.

7.配電箱間隔過小，電器間及相與相間的間隙小，有的還無顯明的斷開點，不但給電工操作帶來了危險性，還將造成雨霧天氣沒法進行帶電改換熔斷器 等工作；配電箱普遍缺乏缺相保護，因缺相燒壞機電的事故時有發(fā)生；有的配電箱沒有采用電子式電能表，沒法實行遠方集中抄表；有的配電箱常年關(guān)著，缺乏例行 檢驗保護。

7. The spacing between distribution boxes is too small, and the gaps between electrical appliances and phases are small, some of which do not have obvious disconnection points. This not only poses a danger to electricians during operation, but also makes it impossible to replace fuses with electricity during rainy and foggy weather; Distribution boxes generally lack phase loss protection, and accidents such as burning out mechanical and electrical components due to phase loss often occur; Some distribution boxes do not use electronic energy meters, making it impossible to implement remote centralized meter reading; Some distribution boxes are kept closed year-round and lack routine inspection and protection.

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