Using SGA is Your Logical Answer
In the natural evolution of utility networks, the playing field for utility engineers is becoming increasingly more complicated. This is not the fault of the utility engineer, but ultimately a symptom of a network which has greater and greater demands placed upon it from reliability and safety methods. As modern Distribution Network Service Providers (DNSPs) are upgrading their networks, utility engineers are often handed the raw end of the deal, being charged with the arduous task of integrating and automating the plethora of intelligent devices which are being harked as the “latest innovation” in electrical systems. Despite all these gimmicks being pushed in the Medium Voltage Electrical and Automation markets, there is an alternative tool which returns to the engineering first principles, allowing utility engineers to develop the control and automation they require in an open source standard to solve much of their challenges with a single device.
When it comes to simple automation schemes, a vast amount of value can be generated even by automating the reclose operation on utility radial feeders. Since most distribution network faults are transient, around 80% of faults will be cleared in the first “reclose” operation of a circuit breaker. This explains why reclosers such as the NOJA Power OSM Series device have been so popular all over the world - they are so simple yet so incredibly effective at providing a genuine return on investment out in the field. Installation of an ACR on the average distribution feeder will pay for itself within a few saved interruptions. Modern Automatic Circuit Reclosers such as the OSM Recloser are usually fully integrated, meaning that they have all sensors, control and communications built in. It is little wonder that ACRs are often referred to as the “building blocks of the Smart Grid” - they are remote controllable, intelligent circuit breakers with open standards of communications directly available. This capability is all fine and well for an individual ACR in an isolated case, but for true smart grid deployment the key is to integrate an entire network worth of intelligent devices, not just the ACRs themselves.
Distribution Network Automation or Smart Grid is the automation of the distribution network to provide better reliability and continuity of electrical supply. When engineered and deployed correctly, it is so economically effective that politicians use the phrase “smart grid” as a vote-winner from a public with a very tenuous grip on the understanding of how electricity works, or even how electricity makes the state money. The issue however is with the actual deployment of this system, as Smart Grid implies the integration of a large amount of Intelligent Electrical Devices in the field to communicate and operate together in harmony. For any engineer who has embarked on the task of even a substation level integration testing project they can understand the complexity of this task, never mind the enormity of accomplishing this on a grid-wide scale. As many of them will tell you, using open source standards is a life saver. When it comes to modern automation, the real heavyweight is IEC 61499.
IEC 61499 is, in simplest terms, an international standard on function block logic. To meet the demands of integration of multiple vendors and types of intelligent equipment, logic is the functional glue that allows systems to work together. Whilst it may be deployed under different trade names in varied equipment, IEC 61499 is a tool which can be used to integrate these IEDs in a harmonious system. NOJA Power’s OSM Series reclosers have IEC 61499 built in as standard, in which it has been named “Smart Grid Automation” or SGA. It is far easier to name a feature for its intended purpose than on the standard upon which it is built.
SGA provides utility engineers with the ability to take any of the signals from the OSM Series ACRs sensors, or any of the data stored in the controller database, and use it to create new custom applications. These custom applications give unprecedented flexibility - engineers can create and modify applications to meet any design criteria. This is particularly important when considering large scale automation, as portability and standard systems allow for the same intellectual property developed for a NOJA Power OSM Recloser to then be deployed into a PLC system, or vice versa. This is fine and well, but the astute reader may ask “if it is a fully integrated recloser system, why would I need to add more functionality?”
This is a very good question to ask, as often the principle of Occam’s Razor is the best to apply in Electrical Engineering circumstances. But when it comes to automation, the simplicity is best left to the operator, so complex systems should be handled by the automation rather than the operator. Engineering out risk is far simpler when the automation system is monitoring the intelligent systems, leaving operators to conduct their supervisory role. Since an SGA IEC 61499 application does not have to be constrained to any individual ACR, there are multiple applications which have been tested and deployed around the world. These include:
- Smart Battery Sensor - Checking battery voltage/capacity drop rate after a loss of AC supply to determine battery health
- Protection Group Network Integration - the change of a protection group on one device publishes its status to all other connected devices, prompting them to also update their settings and locking the entire feeder’s settings in step and preventing malgrades.
- Automation adaptation - Reactively disabling automation schemes between ACRs in periods of severe grid instability.
- Custom SCADA Points - redesigning and aggregating specialist data points for reporting back to a Smart Grid Server.
The last application mentioned above is one of note, as the world ACR proliferation has been met by corresponding Software packages which are fed information from field devices and then charged with making network switching decisions. This style of automation is known as “Centralised Automation” and is the gold standard for Smart Grid deployment methodology. Whilst this seems like a simple idea, in practice the automation software vendor is usually different from the field deployed ACRs, resulting in a mismatch between the data points created in the field and the data used by the automation software for decision making. IEC 61499 in NOJA Power OSM Reclosers allows for utilities to integrate their SCADA point logic into a single point, vastly simplifying the Server side integration system.
“NOJA Power Reclosers suit the most basic auto reclosing application with a simple to configure interface and a user friendly operation panel,” says NOJA Power Group Managing Director Neil O’Sullivan. “They are also suitable for the most advanced functionality possible of any recloser on the market by implementing the functionality that is built in standard including detailed IEC 61850 protection schemes, high speed goose messaging and customer determined logic using the embedded IEC 61499 functionality. We offer the complete solution for low end applications to high end integrated solutions.”
Of course, the first time that any user is charged with developing logic on a new platform it can appear intimidating, but NOJA Power has reported many utility side experts of the IEC 61499 Smart Grid Automation system in their products are young graduate engineers, who have been tasked with working SGA out. The standard report back to the manufacturer from their supervisor was that “it’s like Lego for adults, after a few minutes of learning your way around you start to appreciate just how much can be built with this tool”. NOJA Power appreciates that the first few user minutes of SGA might be daunting but NOJA Power’s Service team are always willing to talk you through the process.
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