Improving Contamination Detectability in Water Distribution Systems using Active Fault Detection

Contamination  event  detection  in  Water  Distribution  Systems  (WDS)  is  an  important  part  of  the overall  procedures  followed by  operators  to  ensure  the  delivery  of  safe  drinking  water  to consumers. In  practice, detection methodologies may use a small number of sensors, which may be placed optimally throughout the network, to monitor water quality. Typically, due to their high costs, only a  small  number  of  these  sensors  are  available  within  each  WDS,  and  as  a  result,  a  part  of  the network is not monitored by sensors. In this paper, we propose a novel methodology for detecting contamination events by increasing the area monitored  by  these  water  quality  sensors. Specifically,  the  proposed  methodology  can  be used in emergency cases when information is available about a possible contamination event in the system,  to  actively  manipulate  WDS  actuators,  by  closing and  opening  valves,  and  alter  the  flow directions within the network. This  is  based  on  the  concept  of  Active  Fault  Detection, in  which  the  control  input  of  a  system  is modified with the aim to improve detectability of a fault.  This active detection scheme, drives flows from specific parts of the network in pre-determined paths, to  allow  the  sensors  to  monitor  the  quality  of  water  from previously  unobserved  parts  of  the network. As a result, the monitoring coverage of the sensors is increased and some contamination events  occurring  within  those  areas  can  be  detected.  Moreover,  the  methodology  facilitates  the isolation of the contamination propagation path and its possible source. We demonstrate how such goals can be achieved on two simple example networks, discuss the benefits of the results and open the discussion for further work in this area.