This Java applet is a simple simulation of a SCADA system being
used to control a small water supply system. The system consists of a number of bores (or water wells)
pumping to a collector tank. A transfer pump station pumps to a larger storage tank, and the
town is supplied by gravity from the storage tank. This system is typical of a very small town, but larger towns
normally have more "zones", but are not very different. The water supply system of even
very large cities can normally be broken down into many such "zones", and the basic principles of control
illustrated here applied.
The applet has a menu bar at the bottom. The options are:
Start/stop - obvious.
Inhibit. Click this to inhibit all bores and pumps
from operating in the "on-peak" tariff periods for electricity supply. You will find that in
winter and autumn/spring the system can be safely operated in this mode, but in summer the town
will run out of water! When running a simulation the display indicates the times when the pumps are inhibited.
Summer, autumn/spring and winter. These options allow you to choose between different demand scenarios.
The bores are organised in two "banks" and are controlled by the level in the collector tank.
Bank 1 (bores 1 and 3) are the first to operate as the tank level falls. If the level continues to fall
Bank 2 (bores 2 and 4) will operate. The display of the "Tank RTU" for the collector tank
shows when the RTU is calling for bank 1 or bank 2.
The main transfer pump station consists of a duty/ standby pair of pumps, which alternate duty to spread the wear.
They cannot be operated together. This pump station is controlled by the level in the main tank.
The display of the "Tank RTU" for the storage tank shows when the RTU is calling for the pump station to operate.
In real water supply systems, much more sophisticated control strategies may be employed than those shown here.
If terms like RTU are unfamiliar to you, you may wish to view
this introduction to SCADA technology.
Note. The style of the schematic of the water supply system as shown in this applet is a
typical method of representation used in SCADA systems. You should be aware that the distances are
not related to the distances of the real system, and in fact the bores and pumps may be many kilometres apart.
This applet has been programmed in Java for a minimum of 800x600 screen size. It also uses JDK 1.1.6 and you will
need a fairly up to date version of Netscape (4.07 works), or IE4.
The applet was programmed in Java by Damyon Wiese.
Scroll down to see the simulator.