Distribution Automation System (DAS)

Author: Seung-Jae Lee, Myongji University, Korea

The article gives insights on the Distribution Automation System (DAS) in Korea

In the modern society, electric utilities are facing many challenges in distribution systems like saturation of existing facilities, growing demand of the high reliability and high quality, increasing penetration of dispersed generations. Under this environment distribution systems are becoming more complex than before and its control and operation is becoming difficult using the traditional technologies and management methods. The remote control and operation of the power grid utilizing the communication and computer technology generates a lot of benefits for the grid operation and it has been widely used in the generation and transmission system level and this concept has been adopted in the low voltage level.

Distribution automation system (DAS) is a computer and communication system with necessary software and hardware facilities for remote monitoring and control of primary distribution feeders from a central server.

DAS collects system data measured from CTs, PTs and other field devices and monitors and assesses the system conditions and controls the grid. DAS continuously updates models of the distribution system in real time so grid operators can better understand distribution system conditions at all times. It acts not only as a decision support system to assist grid operators but also an autonomous agent in taking care of some urgent situations. The key results from deployment of DAS are higher service reliability, higher efficiency of operations and maintenance and reduced cost. Especially huge savings from deferred capital expenses can be obtained from optimized equipment use.

DAS can improve distribution system resilience to extreme weather events such as a storm by automatically limiting the extent of major outages and improving operator ability to diagnose and repair damaged equipment. It also provides a good platform for integration and management of distributed generations.

DAS has been in operation in Korea since 1997. Its development which started in 1991 has been evolving continuously and its history can be divided into four periods. The first period’s DAS started with a basic SCADA functions installed in a PC-based system. During this period, automated switches and RTUs were installed on the field. In the second period, DAS was expanded with many application functions and run in a fully equipped-control center. More advanced functions kept added in the third period and now DAS is going through the new era preparing for the smart grid era. As of today, owing to a long-time investment on DAS, 100 % of distribution feeders of the entire country are supervised and remotely controlled, and there are over 144 DAS control centers in Korea. The average restoration time is reduced to 6.2 minutes after DAS deployment from 73 minutes before. The description of DAS in this article is based on Korean DAS.

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