Integrating Modeling with System Operations

Abstract

Modeling and SCADA (Supervisory Control and Data Acquisition) systems can work together to provide better insights into water systems performance than either can individually. This paper describes the benefits and associated impediments to such a relationship as these two types of systems were not created to work together. Considerable progress has been made in bidirectional sharing of data between SCADA systems and models as data can be imported into models, models can be run from within a SCADA Human Machine Interface (HMI) and results can be viewed in either the HMI or model. BACKGROUND Hydraulic models of water distribution systems were originally developed for use by engineers in planning and design. However, water engineers are not the only group in a water utility that deals with hydraulics on a daily basis. The system operators also routinely make decisions on operations, most often without the aid of a hydraulic model. Operators point out that they have a SCADA (Supervisory Control and Data Acquisition) system that tells them what is occurring in their system and with their experience they can make adequate decisions. SCADA systems only provide a spatially sparse view of the distribution system. While they usually report every tank level and pump station flow, they are very limited on reporting flows and pressures at other points in the distribution system and thus only provide a limited view of the system. SCADA systems are very limited in predicting future performance. The SCADA system usually consists of sensors, analog-to-digital converters, a remote telemetry unit (RTU), communication equipment, a central SCADA computer in the control room and a Human Machine Interface (HMI). Equipment that can be controlled may be locally controlled with a Programmable Logic Controller (PLC) at the pump station or valve, or remotely controlled from a central control room. The RTU’s in the SCADA system are usually polled at a uniform interval which can range from seconds to hours and may also report on exception when some alarm condition is triggered.