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Gold/Mining/Energy : Unitec Int. Controls Inc. -- Ignore unavailable to you. Want to Upgrade?

To: Bobby Yellin who wrote (307)	4/12/1998 2:40:00 PM
From: John B. Smyth	Read Replies (3) \| Respond to of 856

Water is one of the biggest areas for us in the SCADA arena. It is used for fresh water supply, sewage collection and treatment, drainage, irrigation and flood control. Each application has significant benefits, so if you don't mind, I will deal with each one in different postings. I will start with fresh water supply. Fresh water supply is one of the main building blocks of our society's infrastructure. It is also the fastest growing sector as third world countries and collapsing dictatorships turn towards democracy. Democratic people are demanding clean water, health and education from their politicians. Even in places like California and Vancouver (with all its rain) water rationing takes place. I was chatting with a person on the Asian Thread who reported rationing in Kuala Lumpur, Malaysia (a model Asian community). I will start with an example how our SCADA system is used on the fresh water side with the the City of Abbotsford (near Vancouver). Abbotsford obtains its water from two sources. Sixty percent comes from a series of drilled wells and forty percent from the Dewdney Alloette Regional District's (DARD) water reservoir (dams and river intake) in the mountains north of Mission. The water is collected from the various wells and DARD interconnect station and delivered to smaller reservoirs throughout the City where it is tested, treated (as necessary) and stored. From there it is distributed by gravity for domestic, industrial and fire protection purposes. Begininning with the source of supply, water is pumped from the DARD station or the various wells to a reservoir. All of these stations are unmanned, with the equipment working automatically or in some cases semi-automatically. the wells are designed to start on demand if the water level is above a specified level, and will stop automatically when the water table is drawn down. SCADA is used to monitor the Pump stations, set the start/stop limits for the pumps, monitor the condition of the pumps (temperature & vibration) as well as line pressure and flow. If a line breaks or another failure occurs, the SCADA will detect the loss of pressure, change in flow and generate an alarm allowing corrective action to be taken before unnecessary damage occurs. Moving the water to the reservoirs often require booster stations to move the water to higher elevation where it can be gravity fed to the users. Again, the booster station is unmanned and relies on the SCADA system to monitor its safe operation. We have a system in with the City of Burnaby that has several continuous pressure booster stations to supply the residential areas of Capital Hill and in North Burnaby where there is no reservoir. If the booster station fails, the residences are almost immediately out of water. If there is a power failure, standby generators must be brought on-line to restore water service. This is done automatically but the SCADA systems will alert the operators in any event that a problem exists in order to take further corrective action. At the reservoir, SCADA monitors residual chlorine, turbidity (suspended particles) as well as level, inflow and outflow. If equipment failures result in failure to start or stop pumps, over-chlorination or if a line break is detected, the SCADA system will generate alarms and allow remedies to be taken by remote control. An example of its use: several years ago we sold a very small system to Penn State University in Erie Pa. The campus is above the elevation that can be supplied by the City water system pressure. Penn State built a reservoir above the campus and installed a booster station lift the water to the reservoir. After it was in operation for a few weeks, I called the customer to see if everything was functioning OK. It was. I called back a month or two later as I had not heard from them. Everything was OK. Six months later after another call, I learned it was still OK. Having not heard from them, for about two years, I called again as we needed a reference in the U.S. The maintenance superintendent said my call was timely as they just had a near catastrophe. Apparently the booster station and reservoir had been hit by lightning several times over the life of the system, destroying the motor control center, pressure and flow sensors and the like. Because of the extensive damage, they assumed that the SCADA system was also damaged "as it never seemed to do anything anyway". The previous night he said that the guard at the guardhouse where the Master Station was located was annoyed that "the damn alarm kept coming on" He first tried to reset it and finally taped the reset button down to "shut the damn noise off". The tape wouldn't hold the reset button down, and he decided to cut the wires to the alarm. Not knowing what the voltage to the alarm was, he decided to phone the maintenance superintendent to see if it was safe to cut them. The Superintendent asked him what the Alarm was indicating. He replied that it showed the pumps were "ON" and the reservoir overflow alarm was "ON". He then asked what the water level reading was. It showed 4 feet above the alarm point. For some reason, the pump motor controls "stuck in the "ON" position. As the SCADA system normally "did nothing" the operators assumed that it had been damaged along with other equipment in the earlier lightning strikes and ignored it. By the time they got to the site, the water was already overflowing down the embankment. According to the Superintendent, if they hadn't caught it then, there would have been several hundred $K in water damage to the campus. As water is distributed from the reservoir, it must be monitored (pressure and flow) to minimize loss and damage in the event of line breakage and maintain service to the customers. Many water systems use PRV (pressure reduction valve) Stations to protect lines in lower elevations from damage and to equalize line pressure throughout the system. These stations are also (but not as important) monitored and controlled by SCADA. In the United Arab Emirates, we have installed a system which brings water in from 900' drilled wells in the desert for domestic use. This system has a series of "observation wells" drilled around the water wells to monitor the water table level. If the wells are permitted to draw the water table down too low, it will never recover. The observation wells sense the change in the perimeter water table level to avoid over-pumping and insure continuous supply. Aside from providing quality water supply for consumption, fire protection is a major municipal responsibility. SCADA provides "risk management" to reduce the municipalities liability in the even of water system loss during a fire. Any questions here? If not I will next talk about SCADA used for municipal drainage. Regards, JBS