By: Allan Evora & Adam Baker
Not all alarms carry same weight, and not everyone should receive alarms.
Unfortunately, SCADA alarm handling systems don’t always get the design attention they deserve. It’s imperative that both control systems integrators and SCADA end users both understand the importance of proper alarm management. With today’s shrinking O&M budgets, managing by exception makes alarm handling one of the most important functions in a SCADA system. If it is designed properly, it can make your life easier. If done poorly or left to chance, you can put your facility at risk and even decrease employee morale.
In part 1, we talked about the difference between events and alarms. In part 2, we’ll be discussing the importance of prioritizing alarms and using alarm groups.
All actionable conditions warrant attention, but some carry more weight than others. To efficiently manage alarms, your SCADA system needs an alarm priority scheme.
All prioritized alarms should first be based on safety, and then on potential economic impact. For example, if you know the generator starter battery is low at a medical campus central energy plant, that’s a high priority item. Why? If you need to rely on emergency power and can’t start the generator, that’s a gigantic safety issue for patients depending on electrically powered equipment to survive.
But it’s not as black and white as high vs. low priority. Based on the number of critical alarms at any given time, one alarm could be considered a higher priority than another high-level alarm. At a solar energy plant, for example, a substation trip is a higher priority alarm than a malfunctioning inverter. However, a malfunctioning inverter is a higher priority than one tracker actuator not moving.
To keep more important alarms top-of-mind, higher priority alarms should always be the most visible alarm conditions in your HMI. By developing an alarm priority scheme aligned with the expected service levels, operators are not required to decide what is most important. The SCADA system will do it for them.
Coordination of Alarms
Two main problems occur when a SCADA system is designed without coordinating alarms: 1) excessive alarms and 2) increased O&M costs.
Some alarms or conditions in a system will trigger multiple alarms. A circuit breaker that trips or a power supply that fails may trigger a series of alarms related to a loss of power, such as device communication failure. If the system is configured to automatically notify support personnel via a CMMS or alarm notification system, multiple support personnel may be dispatched simultaneously.
Under the prior scenario, dispatching a network technician would be a waste of time since the communication failure had nothing to do with the network or communication equipment. Most modern SCADA systems have advanced alarm handling capabilities that allow sophisticated logic to be applied to evaluating alarm conditions. By coordinating alarms, O&M costs are reduced and excessive alarm conditions are avoided that can lead to operator alarm apathy.
Use Alarm Suppression to Remove the Noise
Alarm suppression is a very powerful but underutilized tool in many SCADA systems. Common scenarios where alarm suppression can come in handy include:
- An instrument out of calibration
- Maintenance or testing conducted on equipment
- A change in operating conditions
All these conditions could result in alarms that an operator has no ability to fix. Not only that, these conditions could lead to equipment going into and out of alarms repeatedly.
The ability to suppress alarms either proactively or in reaction to a specific condition can greatly reduce the amount of nuisance alarms in a system. This means less operator frustration and minimized risk of missing “real” alarms.
Exercise caution with alarm suppression. An audit trail should be developed in which every suppressed alarm should log the operator who placed the alarm into suppression. Time limits should be set for the duration an alarm is allowed to be suppressed. If alarms are allowed to be suppressed indefinitely, I recommend an automatic daily report distributed to facility managers.
Only Send Alarms to Pertinent People/Groups
Because your staff isn’t trained across all the systems in your environment, it doesn’t make sense to notify all of them for each alarm. Alerts should only be sent to the group of individuals that can provide the corrective action to fix the condition that created the alarm.
For example, in an energy plant, you might want to create three alarm groups:
- Chiller plant
- Boiler plant
- Emergency power supply system
If an alarm goes off for the emergency power system group, it will be sent to electricians (not mechanics). And vice versa for chiller and boiler plants.
Today’s alarm handling systems have the ability to send alarms via text message, email and phone call. Not only can internal personnel be notified of alarm conditions, but third-party service providers can also be notified to respond.
Alarm handling systems can be set up to develop the appropriate sequence and associated escalation routine for notification of support personnel. For example, if a generator fails to start, the system will note the day and time and determine if it needs to notify the electrician on duty. If it’s after hours, built in intelligence can tell the system to send a text to the on-call technician. If there is no response or acknowledgement of the alarm after a period of time, the system can then send a notification to the generator service provider.
An alarm management system that implements priorities, coordination, and groups provides owners and operators with an effective tool to keep facilities and assets running effectively, reliably, and safely.
Allan D. Evora is a leading expert in control systems integration and president of Affinity Energy with over 20 years of industry experience working in every capacity of the power automation project life cycle. With a background at Boeing Company and General Electric, Allan made the decision to establish Affinity Energy in 2002. Allan is an alumnus of Syracuse University with a B.S. in Aerospace Engineering, graduate of the NC State Energy Management program, and qualified as a Certified Measurement & Verification Professional (CMVP).
Throughout his career, Allan has demonstrated his passion for providing solutions. In 1990, he developed FIRST (Fast InfraRed Signature Technique), a preliminary design software tool used to rapidly assess rotary craft infrared signatures. In 2008, Allan was the driving force behind the development of Affinity Energy's Utilitrend; a commercially available, cloud-based utility resource trending, tracking, and reporting software.
Allan has been instrumental on large scale integration projects for utilities, universities, airports, financial institutions, medical campus utility plants, and manufacturing corporations, and has worked with SCADA systems since the early ‘90s. A passion for data acquisition, specialty networks, and custom software drives him to incorporate openness, simplicity, and integrity into every design in which he is involved.
Adam Baker is Senior Sales Executive at Affinity Energy with responsibility for providing subject matter expertise in utility-scale solar plant controls, instrumentation, and data acquisition. With 23 years of experience in automation and control, Adam’s previous companies include Rockwell Automation (Allen-Bradley), First Solar, DEPCOM Power, and GE Fanuc Automation.
Adam was instrumental in the development and deployment of three of the largest PV solar power plants in the United States, including 550 MW Topaz Solar in California, 290 MW Agua Caliente Solar in Arizona, and 550 MW Desert Sunlight in the Mojave Desert.
After a 6-year stint in controls design and architecture for the PV solar market, Adam joined Affinity Energy in 2016 and returned to sales leadership, where he has spent most of his career. Adam has a B.S. in Electrical Engineering from the University of Massachusetts, and has been active in environmental and good food movements for several years.