Siemens worked with the Orangeburg, South Carolina Department of Public Utilities to install a power feeder system that reduced power outages for the local Ibuprofen plant.
This manufacturing plant and was experiencing costly power outages and approached Orangeburg DPU demanding a solution, so Siemens worked with the utility to design technology to transfer power in milliseconds rather than minutes.
The plant is the city's largest consumer of electric power, usually requiring up to 10 MW for its operations. The plant was experiencing outages of up to 45 minutes, which was devastating to the facility's output. Each outage required four to five hours worth of downtime to reset all the production equipment.
With the new feeder automation technology, the plant hasn’t experienced a blackout since 2012 and will not have to move locations as it once though it might due to the power issues.
Siemens' idea was to create a peer-to-peer, model-based solution according to smart grid standards established by the Department of Energy (DOE) and the National Institute of Standards and Technology (NIST). SDFA was the result.
In its simplest configuration, SDFA consists of two or more Automation Controllers and a high-speed, IP-based network that allows for IEC 61850 peer-to-peer communications between controllers.
SDFA Automation Controllers mount in new or existing reclosers, switches and substation circuit breakers. The purpose of these Automation Controllers is to detect and locate faults in the feeder circuit, isolate the faulted section, then restore power to the unfaulted sections up to the rated capacity of the alternate power source. Sensing is provided via CT and PT inputs.
SDFA is intended for use in distribution circuits that have two or more power sources, such as loop or mesh distribution networks.
Siemens Distribution Feeder Automation (SDFA) is a decentralized DA solution where all the switching and control logic reside in the Automation Controllers themselves. No centralized controller is used at the enterprise or in the substation.
SDFA can be deployed in brownfield as well as greenfield installations. SDFA Automation Controllers can be installed inside any manufacturers’ switchgear and can be configured to work with the feeder’s existing protection logic.
Siemens offers SDFA as a drop-into-place, turnkey solution, including system design, supply, configuration and site testing. Siemens can also help utilities with the planning, design, supply, configuration and testing of your communications system.
Optional system components include all types of switchgear, wireless communications system, and PC-based and substation-hardened Human Machine Interfaces (HMI).
Siemens Distribution Feeder Automation (SDFA) is extremely fast. Using differential current measurements and IEC 61850’s native peer-to-peer communications capability, SDFA quickly detects faults or loss of power and switches to an alternate power source in as little as 6 cycles. This is fast enough to prevent motor loads from losing synchronization when switching power sources. In addition, an SDFA-ATS solution can be implemented using standard recloser switchgear. When compared to alternative ATS solutions, an SDFA system can result in significant cost savings in both design and construction.
Reclosers and sectionalizers use a trial and error process of over-current measurements, time delays and Time Coordination Curves (TCC) to protect, locate and isolate faults. And in the restoration sequence, reclosers may use additional voltage sensors when backfilling power which adds cost. SDFA operates differently. Using differential current measurements, SDFA quickly detects the precise location of a fault in about 100 milliseconds (via wireless communications) then sectionalizes just the faulted section. It then restores power to the unfaulted sections via the alternate power source, up to the point of its rated capacity.
The result is a highly selective, ultra-fast isolation and restoration scheme that employs fewer switching operations and reduces equipment stress. In addition, differential current measurements greatly simplifies the upfront engineering that would be needed with multiple normally-open points.
And while it is possible to use SDFA Automation Controllers for both the protection and the isolation and restoration functions, utilities can still deploy our SDFA Automation Controllers using conventional recloser-type protection schemes, while retaining SDFA’s isolate and restore logic after recloser lockout. This gives utilities an opportunity to test SDFA’s protection logic in stages before migrating to full smart grid functionality in the future.