Resilience is a key requirement of any mission-critical process such as Water Supply and Sewage Disposal. Resilience means that the functionality of the system can remain largely intact irrespective of plant failure, natural events, planned outages, overloads, human error and other common causes of system failure.
This paper will examine the elements of control and telemetry systems and the consequences of failure of various components of these systems. There will be a focus on isolating failures so that the rest of the system functions correctly, and maintaining a level of functionality system-wide in cases of major breakdowns.
This paper will present a number of real-world situations such as earthquakes, power failures, plant breakdown and human error where a resilient system mitigated the potential damage to the process over which it had control. It will also present a number of illustrative instances where the lack of resilience compounded the difficulties of the initial problem.
In Control and Telemetry Systems, resilience is particularly required in communications, power supply and control philosophies. The paper will present a number of practical examples of how this can be achieved, with an emphasis on simple and robust solutions. There are also examples where over-engineering, such as multiple backups, can actually reduce resilience.