Overview of Grounding for APC UPS Power Supply Unit (Part 1)

Grounding Overview

The grounding of electrical equipment can be mainly divided into three categories: protective grounding, functional grounding, and electromagnetic compatibility grounding. The shielding grounding, signal grounding, lightning protection grounding, anti-static grounding, etc. mentioned in the specifications can all be classified into one of the above three types of grounding. Almost every electrical design specification mentions the design and installation requirements for grounding, including the design of grounding grids, requirements for grounding resistance, connection requirements between equipment and grounding devices, and so on.

Grounding grid and grounding device are generally planned and designed by electrical professionals. The safety grounding, anti-static grounding and lightning protection grounding of each device and unit in petrochemical plant (some chimneys will adopt separate lightning protection grounding device, which is not connected to the large network) will be connected into a huge grounding network, which can be said to be a “public product” used by all systems that need to be grounded. This grounding grid is called “AC grounding device” in some instruments and telecommunication documents. Because there are many functions of grounding, the concepts are easy to be confused, and other majors don’t know much about grounding. Some specified requirements are also debatable. Therefore, in engineering practice, there are many problems in “grounding engineering”, especially in the power supply products, digital products and some electronic instruments and instruments that have been widely used in engineering in recent years. There are many misunderstandings in the design and installation of grounding, and some of them are even wrong.

APC UPS power supply is a common and important power source in engineering, often responsible for supplying power to particularly important loads in the primary load. At present, the UPS power supply widely used in petrochemical enterprises adopts “thyristor” or “GBT” rectification technology, and the inverter unit generally adopts “GBT” module. It can be said that APC UPS power supply is a product that combines “power and electronics” technology. This article takes the analysis of UPS power supply and its grounding system as an example, combined with specifications, to introduce the grounding of petrochemical systems.