Redundant SCADA Architecture for High-Availability Process Control
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Solution Overview
Problem
Existing SCADA architectures for critical industrial processes lack the capacity to manage large volumes of data and commands efficiently, limiting their suitability for high-availability and reliability requirements, especially in systems like electrical networks and power generation plants, and require additional safety systems like SPDS which are not suitable for large, critical processes.
Innovation Solution
A system with two distinct subsystems, one for control and one for assistance, utilizing asynchronous and active redundancy, unidirectional separation, and redundant communication networks to ensure cyclic and event-driven operations, providing centralized and reliable information to operator stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a SCADA architecture is used to control critical industrial processes, then real-time data acquisition and control are achieved, but the system cannot meet high availability and reliability requirements for large-scale critical processes
Solution Approach 1:
The system is divided into multiple independent control modules, each capable of handling specific data processing tasks. This segmentation allows the system to scale horizontally by adding more modules, thereby increasing capacity to manage large volumes of data and commands while maintaining reliability through modular redundancy.
Solution Approach 2:
An intermediary layer is introduced between the data acquisition layer and the control layer, providing buffering, filtering, and preprocessing capabilities. This intermediary architecture enables the system to handle large data volumes efficiently while maintaining real-time control responsiveness and reliability.
2Reliability
If additional safety systems like SPDS are added to ensure safety, then safety requirements are met, but the system complexity increases and additional hardware is required
Solution Approach 1:
Safety functions are merged into the existing control architecture rather than being implemented as separate additional systems. The control modules incorporate built-in safety mechanisms, redundancy management, and fault tolerance capabilities, eliminating the need for separate SPDS systems and reducing overall system complexity.
Solution Approach 2:
The control system performs self-diagnosis, self-monitoring, and automatic fault isolation. Each control module includes embedded safety checks and redundancy management that automatically detect and respond to failures without requiring external safety systems, thereby meeting safety requirements while minimizing complexity.
3Reliability
If high-level safety systems with limited monitoring capacity are used, then safety functions are provided, but they cannot manage large volumes of information required for critical industrial processes
Solution Approach 1:
The monitoring capacity is segmented across multiple distributed control modules, each capable of independently processing and monitoring large volumes of data. This distributed architecture provides both the safety functions and the extensive monitoring capacity needed for critical industrial processes by combining the capabilities of multiple modules.
Solution Approach 2:
The control modules are designed with multi-functional capabilities, simultaneously providing safety monitoring, data acquisition, processing, and control functions. This universal design eliminates the limitation of specialized safety systems with restricted monitoring capacity by making each module capable of handling diverse and large volumes of information.
4Reliability
If redundant systems are implemented to ensure high availability, then system reliability improves, but data duplication and processing overhead increase
Solution Approach 1:
Redundant control modules are pre-configured and stand by in a prepared state, requiring minimal activation overhead when primary modules fail. This preliminary preparation of redundant systems ensures high availability while minimizing the processing overhead associated with activating redundancy only when needed.
Solution Approach 2:
The system implements intelligent feedback mechanisms that monitor the health and performance of control modules in real-time, dynamically adjusting the activation and deactivation of redundant resources. This feedback-driven resource management maintains high availability while optimizing processing overhead by activating redundancy only when actually required.
Data Source
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AI summary
One aspect of the invention relates to a high-availability system, comprising: - a plurality of information-displaying operator stations; - a first sub-system for performing an industrial process that operates cyclically, this first sub-system comprising: - an interface module configured to collect data items each associated with one acquisition time, operating with asynchronous redundancy; - a first processing module configured to sort the received data depending on their acquisition times and to compute first information items, operating with active redundancy; - a first module for managing operator stations, which is configured to send each first information item to the operator stations; - a first duplicated communication network configured to manage exchanges in the first sub-system; - a second sub-system for assisting with performance, comprising: - a second processing module configured to compute second information items from the data items and from the first information items, operating with active redundancy; - a second module for managing operating stations, which is configured to send each second information item to the operator stations; - a second duplicated communication network configured to manage exchanges in the second sub-system; - a separating device configured to manage exchanges between the first sub-system and the second sub-system.