Embedded design for substation automation
As power substations transition from analog to digital communications, they need integrated communications and control systems for managing various equipment, and a high level of I/O capacity and flexibility within their communications infrastructure. Moxa engineers took their experience with industrial serial communication and combined it with Intel’s CPU technology to build an "industrial off-the-shelf" computer system that stands up to the extreme environmental conditions of the power substation.
Utility operators are looking for reliable monitoring solutions that perform many control functions in a single, secure box. "Instead of dedicated communication units, some power substations still use separate control units with proprietary, non-integrated data acquisition, analysis and handling mechanisms," says Moxa European business development manager Hermann Berg. "These aging units can be highly susceptible to frequent communication shutdowns, complicated maintenance procedures and may not maintain stable and reliable operations."
Moxa wanted to build a platform for substation automation that could handle a large number of local area network (LAN) and serial ports while withstanding high temperatures in a fanless, 1U standard rack-mount form factor. "We also had to meet rigorous electromagnetic compatible (EMC) testing requirements for IEC 61850-3, a specification governing communication networks and systems in substations," says Berg. The result was an IEC 61850-3-certified, 18-port, embedded computer designed to service the communications traffic generated by as many as six Ethernet ports and 12 RS-232/ RS-485 ports.
The Moxa design team chose Intel’s mobile product line to power its new rack-mount embedded computer because it offers high levels of computing performance while enabling a fanless solution. "With Intel processors, our energy customers have the computing headroom to run pre-installed operating systems, like Linux, Windows WinCE 6.0, or XP Embedded, in addition to executing many protocol stacks, protocol conversion routines and data pre-processing algorithms needed to monitor and control power systems," says Mark Liu of Moxa.
The new power substation automation system, dubbed the DA-681, has some additional design features to address power and heat concerns. "Our purpose-built L-type heatsink takes heat to the side rather than the top or bottom [in this] this stackable computer," says Berg. To further decrease power consumption, the DA-681 also automatically throttles back (reduces) the operating frequency of the processor, if the system runs hot, through the use of Moxa-designed BIOS features.
Moxa also added an environment for developing application software: a ready-to-run software platform based on energy-industry standards "with easy-to-use serial communication technology to significantly reduce system development effort and time," says Liu. "This is particularly helpful for power automation system integrators, as they no longer need to develop the network from the basic hardware layer."
Intel’s development environment and processor road map helped Moxa speed new product development by an estimated 30 percent, says Lui. Benefits of using Intel architecture processors are:
• The processor’s low-power consumption supports a high working temperature.
• The visibility and availability of Intel processors and chipsets with long life cycle support permit
Moxa to offer a five-year standard product warranty and to "support installations around the world for as long as customers need it."
• The use of Intel architecture processors in Moxa’s modular DA-681 and DA-682 (2U rack-mount) units also allows utility operators to swap out modules as needed.
– Edited by Renee Robbins, senior editor
Control Engineering News Desk