Safe Operations

Seoul City Gas Company adopts automated control system

Incorporated in November 1983, Seoul City Gas Company Limited provides natural gas to residential and commercial consumers in the Seoul and Gyeonggi-do areas. The areas in Seoul include Eupyung-gu, Seodaemun-gu, Chongro-gu, Mapo-gu, Yongsan-gu, Seocho-gu, Gwanak-gu, Dongjak-gu, Yeongdeungpo-gu, Yeoui-do, Yangchon-gu and Gangseo-gu, while those in Gyeonggi-do include Goyang City, Paju City and Kimpo City. Overall, Seoul City Gas provides 2.1 billion cubic metres of gas to over 1.92 million families. The company’s main distribution area is spread across 4,141 km. Of this, 2,897 km lies in Seoul City and 1,244 km in the Gyunggi-do area. Apart from handling domestic operations, Seoul City Gas is involved in developing oil and gas projects overseas as well.

Some of the key competitors of the company are Busan City Gas Company Limited, Daehan City Gas Limited, Kyungdong City Gas Company Limited, Kyungnam Energy Company Limited, Samchully Company Limited and YESCO Company Limited. During January-June 2014, the natural gas sales volume of Seoul City Gas  was about 1,079 million cubic metres (mcm).

Technology initiatives

Seoul City Gas uses an integrated safety system that links its geographic information system (GIS), supervisory control and data acquisition (SCADA) system and management information system (MIS). GIS is used for supporting engineering and operations functions, enhancing customer service, increasing network reliability and reducing costs. It is a system designed to capture, store, manipulate, analyse, manage and present all types of geographically referenced data. It can be seen as a combination of cartography, statistical analysis and database technology. In city gas distribution (CGD) operations, GIS is used to source information on material used for piping, diameter and operating pressure. It is also used for managing issues pertaining to gas leaks, corrosion, excavation damage and unplanned outages. The company deploys GIS in the Web GIS, situation map printout system, pipeline work analysis system, hazard evaluation system, and tablet system.

The gas pipeline network also requires relevant safety and control system applications. For this purpose, CGD companies use SCADA-based automation systems, which incorporate safety shutdown systems at key locations. Seoul City Gas’s SCADA system has a remote terminal unit (RTU) and motor-operated valve (MOV) control functions, which have report-by-exception capabilities. The system’s capabilities include conducting surveillance on gas alerts, power blackout and pressure failure. It also extracts supervisory remote information using the query management system.

Since January 1998, Seoul City Gas’s distribution control system has been managed by Motorola’s MOSCAD, a microprocessor-based RTU with a large memory that can make control decisions on site based on status conditions and values derived from local and remote sources. The MOSCAD system helps in controlling the gas flow, monitoring various pressures on the company’s gas pipe network and sending alarm signals when gas leaks are detected. In order to ensure efficient and timely dispatch for emergency calls, Motorola’s automatic vehicle location (AVL) system enables continuous tracking of the service crew’s location.

The MOSCAD RTU provides the intelligence required to operate SCADA systems. The RTU is programmed to immediately report pressure changes, gas leaks and site tampering. It is also programmed to set gas MOV to the position requested remotely by the dispatcher. The MOSCAD system consists of about 300 MOSCAD RTUs; 44 AVL/global positioning system (GPS) mobile logic units (MLUs); sensors and valves; a control centre; and a conventional ultra high frequency communication system.

The MOSCAD RTU is integrated into each gas network control site. The RTU provides 24 V direct current (DC) to the sensors through a DC-to-DC converter. MOSCAD Discrete Inputs are connected to gas leak detectors, slam-shut valve status indicators, regulating valve position indicators, site door switches, the RTU’s tamper switch, and the battery test unit. In order to ensure continuous RTU operation, each RTU is equipped with a backup battery. A battery test unit, controlled by MOSCAD, alerts the control centre when the battery voltage is too low. The 4-20 milliamps analog inputs are connected to the gas pressure sensors and regulating valve position indicators. Discrete Outputs are connected to the MOV controls.

By using Wonderware’s InTouch software, the MOSCAD system provides a fully redundant PC-based control centre. Redundancy is required to eliminate single points of failure. The control centre interfaces the RTUs via a redundant MOSCAD MCP-T Gateway unit.

In the case of Seoul City Gas, the company’s control centre is connected through two redundant leased line links to two radio sites, which are equipped with MOSCAD units and radios to ensure reliable radio frequency coverage of the entire Seoul region. Every vehicle of the com-pany is equipped with a Motorola radio and MLU, which contains a GPS receiver. The MLU reports the location of the vehicle via radio to the company’s control centre. With this, the dispatcher in the control centre is able to send the nearest crew to the site that requires emergency main-tenance operation.

Key financials

During 2013, Seoul City Gas reported gas sales worth KRW 1,885,866 million, which is slightly higher than the  gas sales of KRW 1,885,154 million registered in 2012. The company witnessed a steep decline of about 30 per cent in its operating income to KRW 11,081 million in 2013. As regards net profit, the company reported a decline of around 2 per cent to KRW 58,517 million during this period.

Further, during January-June 2014, Seoul City Gas’s gas sales stood at about KRW 1,038,484 million. Its operating income was close to

KRW 20,220 million and its net profit was approximately KRW 45,539 million. As on June 30, 2014, Seoul City Gas’s total assets stood at KRW 1,329,442 million and total liabilities at about KRW 484,814 million. Its total equity was close to KRW 844,628 million.

Conclusion

With the incorporation of advanced technology and the implementation of an integrated safety system that links GIS, SCADA and MIS, the company has ensured safe operations. Seoul City Gas will continue to be one of the key suppliers of gas to residential and commercial users in the Seoul and Gyeonggi-do areas of South Korea.

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