仪表及控制系统接地探讨

Discussion on Earthing of Instruments and Control System

根据仪表及控制系统接地的目的,介绍了保护接地的三个作用和工作接地的三个作用。按功能将接地分为:保护接地、工作接地、屏蔽接地、本质安全系统接地、防静电接地和防雷接地等。叙述了不同接地的基本概念、工作原理和电气性质,根据接地的原理讨论了接地的实施方法、接地方式,分析了星型接地、网型接地及星型-网型复合接地的方案以及网型接地的优点。根据安全用电的原则,提倡采用等电位连接、与电气专业共用接地装置。讨论了仪表及控制系统接地的抗干扰作用、相关的接地原则、工程设计和实施的注意事项。

Based on the purpose of the earthing for the instrument and control system,three function for the protective earthing and three function for the working earthing are introduced.Based on the function,the earthing is classified into protective earthing,working earthing,shield earthing,intrinsical safety system earthing,electrostatic protective earthing,lightning protective earthing,etc.Basic concept,working principle and electrical property of different earthing modes are introduced.According to the earthing principle,the implementation method and earthing modes are discussed.The scheme for star bonding,net bonding and star-net mixed bonding as well as the advantage of netbonding are analyzed.According to principle of safety power utilization,adopting equipotential earthing and shared earthing device with electrical engineering,etc are proposed.The principle for anti-electrical disturb effects,relative earthing principle,and notes on engineering design and implementation for the earthing of instrument and control system are discussed.