礦山井下IT配電系統工業絕緣監測工業絕緣監測的應用

安科瑞 華楠

摘要：眾所周知，能源作為經濟發展的重要引擎，堪稱是國民經濟的命脈。采礦業一直是能源工業的重要支柱，我國的礦業生產主要來自井下開采，環境惡劣，就以煤礦為例，煤礦井下存在水、火、瓦斯、煤塵、頂板五大自然災害，加上生產環境復雜，易發生惡性事故。出于**考慮，礦山井下低壓配電系統按規定采用的是IT系統。IT系統就是電源中性點不接地、用電設備外露可導電部分直接接地（PE線）的系統。IT系統的特點是發生第①次接地故障時，接地故障電流僅為非故障相對地的電容電流，其值很小，外露導電部分對地電壓不超過50V，不需要立即切斷故障回路，因此可以保證供電的連續性。但此時非故障相對地電壓會升高1.732倍，對線路耐壓要求提升；同時一旦發生二次接地，則構成危險的相間短路，所以須配置絕緣監測裝置，以便在發生第①次接地時就要及時排除隱患。而對于以煤礦為典型代表的井下環境來說，在開采過程中，由于工作場所空間小、縱深長，加上空氣潮濕、多塵、巷道滴水和積水等諸多惡劣因素，很容易引起電纜和電氣設備老化和絕緣電阻下降，從而導致井下設備、電纜經常發生絕緣強度降低、單相漏電或單相接地故障，不及時處理就可能進一步發展成相間短路。因此，井下作業人員比正常環境下更容易遭受電擊的危險，而且還可能導致瓦斯、煤塵的爆炸。
  顯而易見，對礦山井下IT系統的實時絕緣監測具有更重要的意義。

As we all know, energy is an important engine of economic development and it is also the lifeblood of the national economy. The mining industry has always been the important pillar of the energy industry. China’s mining production mainly comes from underground where the environment is harsh.For example, there are five natural disasters: water, fire, gas, coal dust, and coal seam roof. In addition, the production environment is complex and it’s easy to cause the fatal accidents.
For safety reasons, the low-voltage power distribution system in the mine adopts an IT system. It is a system that neutral is ungrounded and conductive part of the load is directly grounded (PE line). The features of the IT system is that when the first grounding fault occurs, the current of grounding fault is very small, the voltage of exposed conductive part to ground is below 50V, It is unnecessary to cut off the fault circuit immediately, so it can ensure the continuity of power supply. But at this time, the voltage of non-fault relative to ground will increase by 1.732 times, and the requirement for line withstand voltage will increase. At the same time, once a secondary grounding occurs, it will lead to a dangerous phase-to-phase short-circuit, so an insulation monitoring device should be installed which can help eliminate hidden dangers in time when the first grounding occurs.For the coal mine as the typical representative of underground environment , in the process of mining, due to limited space, long in depth, humid air, dustiness, waterlogged roadway, and many other adverse factors, it is easy to cause the cable insulation resistance and electric equipment aging and decline, the underground equipment and cables often suffer from insulation strength reduction, single-phase leakage or single-phase grounding fault, If not handled in time, it may further develop into phase to phase short circuit. As a result, Underground workers are more vulnerable to electric shock than they would be in a regular environment, and may also cause explosion of gas and coal dust.

Obviously, It has more important significance for the real-time insulation monitoring of mine IT system.

2 .國內外絕緣監測儀在線監測現狀

Online monitoring status of insulation monitors at home and abroad

  我國的電氣設計在建國之初師從前蘇聯電氣規范，主要是廣泛的采用TN—C系統，它可以節省一根PE線，比較經濟，但存在很多缺點，如中性線斷裂后設備外殼對地將帶220V危險接觸電壓，不能裝用RCD防電擊等等。改革開放之后我國引進了國際電工學會標準，也隨著我國電氣技術的不斷提高，在應用中TN-S、TT、IT系統得到了一定程度的推廣和應用，以IT系統為例，在醫療IT方面目前應用比較成熟，但在很多工業場合，由于對接地系統的理解和應用尚不盡深入和全方面，比如煤礦井下場合比較缺乏國產絕緣監測裝置就是一個證明。目前礦用井下IT系統的絕緣監測裝置以進口品牌為主，歐美等發達國家已經較廣泛地在IT配電網絡中應用絕緣檢測技術，而且經過長期的在線運行使發達國家積累了大量監測數據和經驗，這是目前國內生產廠家需要學習和追趕的。

但采用進口品牌絕緣監測裝置造價昂貴，而且人機界面往往是英文，不利于現場人員的使用，在這種背景下，也不斷有國內企業逐步推出了自己的工業用絕緣監測裝置，其中就包括了安科瑞電氣有限公司的AIM-T系列絕緣監測儀。

At the beginning of the founding of the People's Republic of China, China's electrical design was based on the former Soviet Union's electrical code, mainly using TN-C system . It can save a PE line, which is more economical, but there are many disadvantages, such as, after the neutral line breaks, the equipment shell to the ground will have a dangerous contact voltage of 220 V, and RCD cannot be installed to prevent electric shock, etc. After the reform and opening up, China has introduced the standards of IEC, and with the continuous improvement of electrical technology in China, TN-S, TT and IT systems have been promoted and applied to a certain extent. For example, the application in medical IT is relatively mature at present, but in many industrial occasions, due to the understanding and application of grounding system is not thorough and comprehensive, for example, the lack of domestic insulation monitoring device in coal mine is a proof.At present, the insulation monitoring devices of mine underground IT system are mainly imported brands.Insulation detection technology have been widely used in IT distribution network in developed countries such as Europe and the United States. And they have accumulated a lot of monitoring data and experience after a long-term online operation. This is what domestic manufacturers need to learn and catch up with.
   However, it is expensive to use imported brand insulation monitoring devices, and the human-computer interface is often in English, which is not conducive to the use of field workers. There are also domesticenterprises whichhave gradually launched their own industrial insulation monitoring devices, including the AIM-T series insulation monitoring devices of Acrel.

3 安科瑞工業絕緣監測儀

 Acrel industrial insulation monitor