Steve Hanawalt is one of the founders of Power Factors and an expert on solar performance analytics. Power Factors provides a real-time asset performance management software platform called Drive for the renewable power industry.
In a previous article, we asked Steve to cover how utilizing solar performance analytics can reduce costs and improve productivity at SCADA plants. Now, he shares his expertise on revenue boosting analytics for DAS.
Drive is an intelligent overlay that sits on top of the DAS plant communications layer to enhance DAS monitoring and alarming. Because Drive has a historical record of all the alarms that have ever fired against an asset and all the maintenance performed, it has a richer data set from which to understand the root causes of asset failure.
Let's take as an example a forced inverter outage. The DAS notifies the operator of the outage with a specific ground fault error code. Drive can see that the same fault has occurred three times in the past six months. Not only that, it always occurs during a rainfall event at the plant.
Drive's knowledge base can make that connection between the specific failure mode and rain events. The operator can then send out a field tech to find the problem, armed with specific information to inform the troubleshooting process. They discover that one of the conductors that connects the inverter to the modules has a failed insulator, so rain can trickle down into the ground and trip the inverter offline. Instead of just resetting the inverter over and over again, the operator can fix the root problem, improving inverter uptime.
This would be difficult for the operator to figure out from the DAS alarms alone. Drive provides a much richer set of data from which to do a root cause analysis and improve plant production.
Since Drive has visibility into all of the DAS data monitoring points and alarms, it not only can monitor them but can also add value through the implementation of intelligent events. In general, an event is a business or engineering rule that is triggered when an abnormal condition is present in the solar PV plant. The event engine is the rule-based tool that throws off a notification/alarm when the trigger threshold is reached.
Let's look at our inverter failure example again. When the forced outage alarm comes from the DAS, Drive captures this event data and auto-categorizes it using an international failure classification standard. Drive's additional data layer transforms just another alarm coming from the DAS into a whole set of operating and business metrics, such as:
This is rich and comprehensive information, not just data, that can be used to enhance decision-making and operational efficiency.
Solar plants also have what we call very "noisy" data. Without data curation—cleansing and validating the data before it goes into the event engine—the engine throws off a bunch of what statisticians call false positives. Operators call them nuisance alarms.
Drive's data curation and validation engine uses sophisticated rules to qualify the alerts coming from the DAS to make sure they're valid. This means the quality and integrity of the alarms are much higher. In our inverter example, both the DAS and Drive can signal an outage, but Drive can look at the totality of all the plant data and calculate if the alarm is a true alert that requires action.
Lastly, Drive can generate production and performance reports from the curated data, using a rich set of analytics as well as integration with the field service management module. Drive can look at all of the physical maintenance that’s been performed against site assets with a whole set of work orders, failure codes, action codes and cause codes. This reporting gives operators and engineers deeper insights into the root causes of equipment failure, thereby improving system uptime and revenue.
Typical solar power installations do not have sensors installed in the DC array even though the majority of PV performance losses occur in this part of the power plant equipment.
Why? Because the cost of instrumenting the plant at this scale is not considered economical for solar PV plants, and because monitoring systems have historically not been able to consume and process so much data. The sheer volume and velocity of data coming in is too much for them to handle.
Drive's advanced analytics software module is able to solve this problem using digital twin performance signatures. This technology can identify specific failure modes in the DC array using normally instrumented data from the DAS. Drive can detect DC performance problems like stuck trackers, blown fuses, shading and module soiling without the need for additional plant hardware or software. As a result, we estimate the typical project will see an improvement in equipment uptime and performance resulting in a 1-3% plant revenue upside.
There are many benefits of hosting a software application in the cloud, but perhaps the most important is that additional computing resources can be spooled up automatically without a loss of connection to the plant or negative impacts to computing performance. The intrinsic extensibility of cloud computing means that large processing tasks, like DC performance analytic processing, can be essentially run in real-time to improve the detection of transient performance losses.
For example, Drive can detect the occurrence of sub-interval curtailment of plant equipment. Sub-interval curtailment is usually "hidden" from traditional monitoring systems because their sampling frequency is so coarse that short interval equipment derates are not visible to the plant operator. Little performance losses go undetected, chipping away at optimal plant revenue. As the saying goes, "you cannot correct what you don't see." Drive allows you to see these previously invisible losses so you can recover them.
Having a local plant DAS is necessary and very important. But when you put an intelligent monitoring layer on top of it, you can not only see that plant, but all of the plants in the totality of your operation. You can make more intelligent and optimal operating decisions because you're doing what's called portfolio optimization of the plants, not just plant level optimization. It's known in the power industry that when you optimize the operation of all generating units or plants at one time, you have much higher revenue and return on investment than doing each as an isolated individual plant. That becomes a very powerful way of operating your facility.
That's why we at Power Factors see our partnership with Nor-Cal as a truly symbiotic relationship—one where the whole is greater than the sum of the parts. Nor-Cal's DAS systems and our Drive software together create asset performance management platforms that improve productivity and reduce operational costs.