Integrating Utility Networks
Companies involved in energy or energy-related transmission and distribution are finding that the lifecycles of SCADA (supervisory control and data acquisition) systems are not as long as they once were, due to rapidly developing technologies and changing market requirements driven by ongoing deregulation, liberalization, and privatization of energy-related markets.
Companies involved in energy or energy-related transmission and distribution are finding that the lifecycles of SCADA (supervisory control and data acquisition) systems are not as long as they once were, due to rapidly developing technologies and changing market requirements driven by ongoing deregulation, liberalization, and privatization of energy-related markets. As a result, it is more common to see requirements for integrating traditional SCADA functionality with external commercial and technical applications, such as network information systems, customer information systems, computerized maintenance management systems, and geographical information systems.
Control systems currently available from most large control system vendors offer advanced integration opportunities.
The basic building blocks required of a control system capable of integrating third-party applications include:
Component-based, object-oriented system architecture;
A SCADA server that can be changed without changing HMI;
OPC connectivity; and
Ability to re-use programming for third-party application integration in future projects.
SCADA systems facilitate operation of energy and energy-related networks; a growing industry trend is use of a multi-utility SCADA system (see graphic). Such a SCADA system must include utility-specific applications to empower operators and support engineers to access all process control information within an enterprise in real time and in a user-friendly manner to improve enterprise performance.
Schematic overview of multi-utility SCADA depicts network management setup of a multi-utility SCADA system integrated with third-party applications.
Utility-specific applications, such as leak detection, pipeline simulation, outage and leakage management, usually differ in software architecture, and are not difficult to integrate if they are component-based applications supporting integration technologies like CORBA, OPC, and OLE, and run on the same platforms as the SCADA system. However, integrating monolithic application suites of software with poorly defined application programming interfaces (APIs) is difficult and ill-advised due to the high costs of integration involved. Unfortunately, monolithic types of legacy applications are often used in energy and energy-related transmission and distribution systems.
The system architecture shown in 'SCADA system with integration platform' graphic illustrates one approach to SCADA network integration with utility-specific applications. The graphic shows process data being transferred between SCADA system and integration platform, using OPC (a proprietary interface can be used if desired).
Integration platform architecture for multi-utility SCADA extension hinges on control system API with SCADA API.
In such a configuration, the network control system includes functionality of the SCADA system and the integration platform. Process data caching with a standard OPC interface for SCADA allows a high degree of communication performance because of the short access time for retrieving cached data from process data cache.
Using ABB's 800xA system as an example, third-party, utility-specific applications can be integrated as 'aspect systems'—they become object-oriented components of the integration platform using a SCADA system connection.
Following this type of integration architecture, in most cases, permits re-use of the integration platform in other projects.
Additional opportunities for extending integration possibilities are available if changes are made to the SCADA HMI. For example, it is possible to substitute existing SCADA HMI modules with the ones from the integration platform, like alarm and event lists, trend displays, and faceplates with those from third-party applications (such as process viewers or distance plots). As a result, components of a given SCADA system may be defined for each application, depending on customer requirements and future re-use opportunities. User management functionalities on the HMI level can be re-used from the integration platform.
Common SCADA network configuration used to enable third-party application integration.
In such an extended architecture (as shown in the 'SCADA system network configuration' graphic), the SCADA system core includes: real-time database (responsible for handling process variables related to data acquisition, control commands, alarm handling, and archiving); process connection module that interfaces controllers of I/O devices; processing module; and SCADA API. The process connection module can poll the controllers of I/O devices at a user-defined polling rate.
The server may reside on the same computer as the SCADA server software or on a separate computer. The client is usually the operator workstation.
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Integrated benefits of networked applications
Key benefits provided by the integration platform for network management applications include:
Component-based network control architecture;
Low-cost company-wide migration opportunities; and
Re-use of third-party, utility-specific applications.
Yauheni Veryha, scientist, and Markus Gauder, M.Sc., work in the Manufacturing and Automation Services Group, ABB Corporate Research Center, Germany;