Description

DC power systems provide continuous DC voltage through multiple outputs. Typically, these devices accept single-phase or three-phase AC inputs with voltages of 115 or 230 VAC and frequencies of 50, 60, or 400 Hz. Most DC power systems include a battery backup for continuous output. Devices with multiple outputs can provide a range of DC voltages. To compensate for increases in temperature, some DC power systems are fan cooled, water cooled, or includes an integral heat sink. Overload and overvoltage features provide additional protection. Weatherproof DC power systems are rated for outdoor use and can withstand a variety of environmental conditions.   

Line and Load Regulation

   
DC power systems vary in terms of line regulation and load regulation. Line regulation is the maximum steady-state amount that output voltage changes as a result of a specified change in input line voltage. Typically, the specified change is either a 10% change in the input voltage, or the variation of line voltage from the minimum to maximum value. Load regulation is the maximum steady-state amount that output voltage changes as a result of a specified change in load. Load regulation is expressed as a percent change in output voltage caused by increasing load from half load to full load.

Types of Display

   
There are several ways to view information from DC power systems. Some devices include an analog meter or simple visual indicator such as a needle. Others have a digital display for numerical values. DC power systems with a computer interface often provide graphical or multi-line displays. Devices that can be monitored via the Web, or that have remote on / off switches, provide remote manageability. Operators who monitor DC power systems with power correction features can adjust the phase difference between voltage and current in order to optimize power output. 

Uses

   
DC power systems are available in a variety of shapes and sizes and are critical components in a variety of telecommunications networks, including cable, wireless, fiber optic, and public switched telephone network (PSTN) applications. Many of these devices are hot swappable so that power systems can be replaced without network shutdowns. Redundant DC power systems also allow networks to continue to function while operators perform maintenance. 

Standards

IEEE 1653.4 - DC traction power system field testing and acceptance criteria forsystem applications up to 1500 V DC nominal

IEEE 1709 - Recommended practice for 1 kv medium-voltage DC power systems on ships

ATIS 0600311 - DS power systems 

References

Image Credit:

Acopian Power Supplies | TPL, Inc. | Alpha Technologies Ltd.