Recent advances in PLC, SCADA and leak detection system technologies lead to the development of a highly integrated control system. Interconnected with fiber optic communication speeds (OC-1), this level of integration moves away from the historic model of stand-alone field controllers connected over low speed communication links to a centralized control center which, in turn, exchanges data from the host system to stand-alone leak detection processors.
A new system design approach utilized familiar pipeline control elements such as PLC controllers and MODBUS communication protocols in combination with elements more typically associated with an office environment such as Windows NT servers, PC compatible computers, and Ethernet TCP/IP communications networks. These open-architecture components were used to fully develop, debug and test the SCADA system prior to system startup. The pipeline simulator is used as the centerpiece for this process to perform thorough operational validation of the system long before initial linefill. Once the various components were fully tested they were exported to the physical system in an operational state.
The result is nearly seamless control systems supported by high data rates, high model speeds, common databases, and multi-channel communications. The increased level of integration has had dramatic impacts in leak detection, system safety, engineering development, operator training, and overall reliability of the control systems.
The following paper presents a narrative overview of these new developments in the context of an implementation on Pacific Pipeline System (PPS). PPS is a recently constructed and commissioned 209 km (130 mile), 50.8 cm (20″) diameter, hot crude oil pipeline between the southern portion of California’s San Joaquin Valley and refineries in the Los Angeles basin. Following the Interstate 5 corridor over the “Grapevine”, Tejon Pass, Angeles National Forest and through heavily populated areas, this pipeline traverses some of the most environmentally and safety sensitive regions in the United States. The joint federal and state Environmental Impact Report / Environmental Impact Statement (EIR/EIS) set high hurdles for leak detection and control system performance. The historic control architecture and technologies were not adequate.
This paper provides an overview of the environmental and physical constraints of the Pacific Pipeline System alignment, hydraulics, pumping and metering equipment, and block valve locations. It also discusses their impact on the design, programming and commissioning of a SCADA system meeting the requirements of the EIR/EIS. The paper then describes in more detail the fiber-optic communication system, control system architecture, SCADA system, leak detection models, simulator models and implementation methods, along with the engineering decisions leading to a comprehensive solution for the SCADA and leak detection requirements.