SCADA Design for Extreme Weather
Sparky has been talking on and on about SCADA systems. I can’t figure out why he is excited about flying to Minnesota, and northern Minnesota of all places. The weather report this week is not good. By Thanksgiving Northern, Minnesota will be freezing temperatures and buried in snow. I finally had to ask him, what does SCADA mean and why he was so excited about it and freezing weather?
What Does SCADA Mean?
Supervisory Control and Data Acquisition Sytems refer to remotely located systems that automatically collect data on electrical equipment for monitoring and control. The arrangements are designed to reduce the cost of having a person physically reading instruments and changing settings of operating controls in these remote areas. It also allows for this monitoring/supervising multiple systems in one central location. These systems existed long before the computerization of cloud-based networks and SOC, security operation centers, for computer networks.
Why is Weather an Issue in SCADA Design?
The weather is why "Sparky" was getting excited? He tells me these very remote systems in such places as Northern Minnesota and similar climates around the world have unique design requirements. The electronic equipment and computer systems required for monitoring and controlling the remote devices must be able to operate in extreme conditions of both heat and cold. Since many of the enclosures containing the sensitive equipment are in environmentally controlled buildings, the required protective devices must be relatively compact.
Sparky has been asked to go to the most remote locations in the iron ore mining area of Minnesota to research the conditions of the SCADA systems used by a mining company. After then, he is going to Wyoming, Montana, and even more remote locations in Canada for methods used to monitor the natural gas production & pipeline controls. This research is how his company designs new devices to serve these companies in their design of more modern systems.
What Type of Applications Use SCADA?
Applications for remote monitoring and control systems exist in almost every industrial sector, including homebuilding. Consider the security and monitoring of your own home. Even the primary system is an excellent example of SCADA. Newer methods allow the homeowner to monitor and control lights, garage doors, heating & cooling, video security cameras, and even the locks on their doors. The home applications don’t require much environmental protection. The devices like cameras or sensors mounted outside in the weather enclosed in housings that are moisture and weatherproof. In really severe conditions of cold or direct sunlight, these devices could fail. Due to expense, nothing more sophisticated than the enclosures are used to protect them.
Industrial Applications for SCADA
- Power Generation
- Power Distribution
- Gas & Oil Installations
- Gas & Oil Pipelines
- Wind Mills
- Solar Power Fields
- Material Handling
- Hydro-electric Dams
- Nuclear Facilities
- Security Systems
- Border Protection
- Water & Sewage Plants
- Space Exploration
- Mass Transit
- Logistic Supply Chains
- Ocean Shipping
- Traffic Signals
- Commercial Buildings
- Public & Private Infrastructure
- Offshore Drilling
- Military & Commercial Drones
Location, Location, Location of System is Key Factor. Not all of the listed applications include exposure to extreme weather, but many of them are in remote locations. From this list, most of us can imagine the extreme conditions that these automated, mostly computerized systems operate in during their lifetime.
How Do SCADA Systems Work?
I’ll never learn. I made the mistake of asking Sparky how SCADA systems work. He started the explanation with a story from his college days. It seems that a fellow engineering student that was an Army vet told him about this job at the college where they could study for eight hours a night! It seems that the college was looking for “mechanical types” to monitor the college’s steam heat boilers and power systems on the night shift.
The job was simple. Once per hour, one of the "mechanics" had to walk around and record the instrument readings for pressure, volume, and flow mounted on all the tanks, boilers, pipes, and power systems. There were two people each shift because one had to remain in front of a wall full of video screens. These screens were from cameras monitoring all of the entrances to the campus buildings. If someone wanted access after hours, they would be identified and allowed in one of the many buildings on campus.
On the 11 - 7 AM shift, there wasn’t much going on, especially on weekends. The two of them would study engineering and math homework all night between 10 minutes rounds to read the instruments. On a side note, this resulted in both of them getting straight A’s in all the courses. The point of the story is essentially a manual SCADA, supervisory control, and data acquisition system. The systems have advanced considerably since the early ’70s.
Modern systems use a myriad of sensing devices to collect data from the operating systems. This information is collected and accumulated for transmission at the remote location by data acquisition software and computers. Depending on the network, some of the data is recorded & processed at the remote site. In other systems, all the information is sent back to a central monitoring and control station. With either case, preprogrammed parameters in the operations will indicate alarm conditions or requirements for adjustments of valves or other actuators. When the error or fault condition occurs, a signal is sent locally or from the central station to make necessary adjustments to the controlling devices.
Todays’ systems are going farther than anyone ever imagined with the coming of the IoT, Internet of Things evolution. The value of these systems is reduced response time, labor costs, better-operating efficiencies, and minimize waste of materials.
How Are SCADA Systems Designed for Extreme Conditions?
Industrial applications that require remote sensing are often located in inhospitable locations as diverse as desert, northern regions, and the bottom of the ocean. Even the top of a building in Chicago temperature could reach 60 degrees below zero wind chill during the winter months.
High temperatures locations use fans and cooling systems. Temperature limits of industrial electronics can range from -45 to 85 degrees C. With the temperature increase or decrease, and the cost goes up with these components. It isn’t always practical or cost-effective to design with the most expensive parts to counteract high or low temperatures. SCADA applications may also require a mix of components and devices, necessitating a design for the mean or most economical temperature tolerant devices.
All these systems are housed in environmentally designed enclosures but often require special considerations for their location. See our previous post on “Condensation in Electronic Enclosures” or “Immersion Heaters.”
DBK USA offers a wide range of PTC heating devices to help protect electronic devices from cold temperatures and controls to maintain desired temperatures. Many are off the shelf products that can be ordered online for testing or directly installed into your SCADA systems.