IEEE 946-2020 pdf free.IEE E Recommended Practice for the Design of DC Power Systems for Stationary Applications.
The considerations of each of these different components and the issue of load voltage and other load specifics are discussed in terms of their effect on the design of the whole system. Guidance on short-circuit calculation and contribution of different de power system components is also offered to improve reliabilit, performance, and safety of the installation.
1.2 Purpose The purpose of this document is to provide the user with information and recommendations concerming sizing and designing dc power systems in stationary applications.While the recommended practices in this document apply to dc power systems in substations, additional guidance for substations is provided in IEEE Std 1818.2.
4. Organization of this recommended practice
Stationary dc power systems appear in many applications and industries. All have certain commonalities. while some have some unique requirements. It should be noted that these commonalities or unique requirements are derived from variance in environmental conditions, reliability expectations. and importance of application. That translates to specific feature requirements or technology differences (thyristor versus high-frequency switched mode chargers, or lead-acid versus Ni-Cd batteries) that can provide an engineering approach to the selection/design of dc power systems. For example. a substation charger can be used in a telecom application and vice versa as long as it can meet the requirements.
l)escribing every application is beyond the scope of this document, therefore the three dominant applications are generation, substations, and telecommunications. Large telecommunication carriers may have their own internal dc power system standards that examine dc power systems and their requirements in detail. This is also beyond the scope of this document, but is worthy of a mention. In this recommended practice. each section includes subparagraphs reserved for these three applications when there are unique requirements. For other industrial applications, one can use the recommendations—in part or as a whole—of one ofthe three dominant applications. For example, substation application recommendations may be used, where applicable, for the design of an industrial process control dc power system. It is not the intent of this recommended practice to exclude other industrial applications. L.ead-acid and nickel-cadmium batteries are the types of batteries primarily used in these applications. Some other battery technologies may be used but are not fully addressed in this document.
5. Description and operation
DC power systems provide reliable power to critical loads. Examples of critical loads include auxiliary motors, circuit breakers and switchgear. relays, solenoids. SCADA. telecommunications equipment. invcrters, emergency lighting equipment. fire suppression equipment. etc.
5.1 General
A dc system nommlly consists of one or more battery strings, one or more battery chargersJrectifiers and one or more distribution panels. If a battery isolation/protective device is used, refer to the battery protection guidelines of IEEE Sid 1375. Refer to simplified typical connection in Figure I for the line ofdemarcation that limits the application of IEEE 946 versus IEEE 1375.IEEE 946 pdf download.