IEEE Std 1250-2011 pdf download – IEEE Guide for Identifying and Improving Voltage Quality in Power Systems

02-24-2022 comment

IEEE Std 1250-2011 pdf download – IEEE Guide for Identifying and Improving Voltage Quality in Power Systems.
2.2 Overview of power systems Power systems are usually thought of as having three main divisions: generation, transmission, and distribution. Figure 1 is an oversimplified diagram of a typical U.S. electric power system. In reality, there are many exceptions such as the fact that some large industrial customers are actually served by substations directly from the transmission system and some small generators may feed directly into the distribution system.
Interconnection of the generation, transmission, and distribution systems takes place in an electrical substation. Substations may include transformers that raise or lower the voltage depending on the need. A substation that has a step-up transformer increases the voltage while decreasing the current, whereas a step- down transformer decreases the voltage while increasing the current for distribution. Electric power may flow through several substations between generating plants and consumers, and it may be changed in voltage several times. The generation and transmission components are typically connected in an interconnected grid fashion. Within the “grid,” the transmission lines transport bulk power for long distances that typically cross multiple service territories and multiple utilities. Figure 2 shows a simple transmission system, referred to as a transmission network, illustrating how most of the substation buses have more than one source. In most circumstances, the loss of a single line or generator should not cause overloads within the remaining network. This offers a high degree of reliability because power can be maintained to most buses even with the loss of a line or source.
Distribution lines (commonly called primaries) are usually not interconnected but are designed in a radial fashion except in some cities that use a mesh distribution scheme. Radial distribution systems consist of a source originating at a substation in which the system voltage is stepped down (Figure 3). The distribution bus has breakers that feed lines (feeders) that carry the power to many customers in an area. There are usually line protective components (reclosers and fuses) downstream of the substation breaker on distribution lines. These components create situations in which only a portion of the distribution line may need to be de-energized to clear a fault (short circuit), thereby saving many customers on the line from experiencing interruptions unnecessarily.

Download infomation Go to download
Note: If you can share this website on your Facebook,Twitter or others,I will share more.


Anonymous netizen Fill in information