The goal of this work is creation of optimal grounding model at the substation 10/0.4 kV of the urban power distribution network. The electric current can pose a major threat to the man’s life and health. In addition...The goal of this work is creation of optimal grounding model at the substation 10/0.4 kV of the urban power distribution network. The electric current can pose a major threat to the man’s life and health. In addition to pose a threat for health, the rise of the short circuit, as a consequence of insulation faults, poses a threat to retirement of electric systems and fire risks. The reliable grounding system design has significant implications for protection of human being as well as for electrical facility protection. The set objective was performed on the base of analytical and software-based methods. Analytical method gives a qualitative indication at each step in analysis. It also allows evaluating the values effect on the result, but the method is not susceptible of tolerable accuracy, that is why analytical method serves as initial approximation in differentiating. Specified estimation can be performed in such software package as MATLAB or ETAP. Software-based estimation is based on the finite element method (FEM), the main advantage of which is the ability to create different forms of grounding and allows obtaining distribution graphs of the step potential on the earth’s surface and touch potential. The calculation results in comparison of analytical and software-based methods taking into account the grounding optimization. There are conclusions on the most effective ground network.展开更多
苯可以通过完整皮肤吸收引起全身效应且为已确认的人类致癌物质,通常存在于油漆及汽油等产品中。随着技术的革新,油漆中的苯逐渐被甲苯、二甲苯取代。当产品中的苯含量<0.1%,其化学品安全说明书(material safety data sheet,MSDS)成...苯可以通过完整皮肤吸收引起全身效应且为已确认的人类致癌物质,通常存在于油漆及汽油等产品中。随着技术的革新,油漆中的苯逐渐被甲苯、二甲苯取代。当产品中的苯含量<0.1%,其化学品安全说明书(material safety data sheet,MSDS)成分信息中可不标注,这对于苯的认定、接触人群的界定、职业健康检查项目的确定以及职业接触人群的管理存在一定的安全隐患。展开更多
文摘The goal of this work is creation of optimal grounding model at the substation 10/0.4 kV of the urban power distribution network. The electric current can pose a major threat to the man’s life and health. In addition to pose a threat for health, the rise of the short circuit, as a consequence of insulation faults, poses a threat to retirement of electric systems and fire risks. The reliable grounding system design has significant implications for protection of human being as well as for electrical facility protection. The set objective was performed on the base of analytical and software-based methods. Analytical method gives a qualitative indication at each step in analysis. It also allows evaluating the values effect on the result, but the method is not susceptible of tolerable accuracy, that is why analytical method serves as initial approximation in differentiating. Specified estimation can be performed in such software package as MATLAB or ETAP. Software-based estimation is based on the finite element method (FEM), the main advantage of which is the ability to create different forms of grounding and allows obtaining distribution graphs of the step potential on the earth’s surface and touch potential. The calculation results in comparison of analytical and software-based methods taking into account the grounding optimization. There are conclusions on the most effective ground network.
文摘苯可以通过完整皮肤吸收引起全身效应且为已确认的人类致癌物质,通常存在于油漆及汽油等产品中。随着技术的革新,油漆中的苯逐渐被甲苯、二甲苯取代。当产品中的苯含量<0.1%,其化学品安全说明书(material safety data sheet,MSDS)成分信息中可不标注,这对于苯的认定、接触人群的界定、职业健康检查项目的确定以及职业接触人群的管理存在一定的安全隐患。
