Instrumentation & Control - Enablers for self healing smart grids - Part 2
In this blog I would like to continue the topic that I started in my last blog, i.e. the role of Instrumentation & Control in the Self Healing Smart Grids. As I mentioned one of the less talked about topic (at least publically) is the Instrumentation & Control in the Smart Grid forums and conferences. As mentioned in my previous blog I would like to discuss one of the most common use case in the context of smart grids and give my perspective of how that particular use case with help of better instrumentation & control will enable implementation of self healing smart grids.
Let's first talk about different layers of automation. I would like to term the automation in three levels, Level 1, Level 2 and Level 3. My fellow readers who are familiar with Process Automation industry will be able to relate to the various levels of automation. In my view the definition of these levels of automation can be given as follows:
1. Level 1: It's the lowest level of automation that is implemented using advance and intelligent telemetry and protection field devices e.g. smart switches, relays, sensors etc. They form the backbone of level 2 and 3 automation.
2. Level 2: It's the layer on top of Level 1 automation and let's call it local control & automation applications layer. This can also be termed as the micro grid monitoring & control layer. At this level the supervisory data acquisition and control is performed at a local level i.e. within a pre-defined, self sufficient island of the grid network.
3. Level 3: This automation layer is classic distribution or substation control room where SCADA and advance distribution automation/management applications function in conjunction with the Level 2 and hence Level 1 automation systems. This is the centralized system that co-ordinates and manages functions of Level 2 automation systems such that the local controls at level 2 in one area (microgrid) don't affect grid operation in other parts of the grid network. This is important as the micro grid or level 2 automation will be theoretically isolated from the overall electrical grid or I would say rather will be self sufficient to manage the grid per localized needs from generation and load perspective, but in reality it will still be part of larger electrical grid network.
Now the use case that I want to talk in this blog is the Outage Management Use Case. This is the most talked about use case as AMI implementation enables Utility's OMS to automatically detect outages and service restoration. The very same use case can be greatly enhanced with the help of better instrumentation and control. With the help of advance telemetry and protection control based automation OMS will not only be able to detect outages as soon as they happen but also with the help of advance DMS (Distribution Management System) applications it will be able to automatically restore the service to affected customers.
Now, how will it happen? Let's consider with advance sensors like fault sensors, analog measurement sensors and disturbance recorders placed at key strategic locations can give status of the electrical grid (or say pulse of the electrical network) almost instantaneously, similarly the status of smart switch and relays can be instantenously known using fast SCADA systems. If above conditions are met then it will be possible to detect the outage condition much faster than what Smart Meter based outage detection, because SCADA will know open status of a circuit breaker even before Smart Meter can detect that it lost power (sending "Last Gasp Event" comes much later). Similarly using advance DMS applications like Fault Location Isolation and Service Restoration (FLISR) and with the help of digital relays and advance control network (IEDs etc) the service to the affected customers will be restored even before the OMS creates an Outage Incident (Momentary Outage Incident will still be recorded).
This Use Case can further be detailed out and I can keep writing, but I will rather stop here so that I don't lose your interest. The only point I wanted to make here is that it's the Level 1 automation (i.e. Instrumentation & Control layer) that will enable the actual self healing grids.
Now, is it possible to make self-healing grids? In theory YES, but practically not in the very near future. Unless the concept of micro grids picks up it will be very difficult to see self-healing grid in reality. Please let me know your comments and if I should elaborate more on this particular use case in the context of Instrumentation & Control.
By the way Level 1 automation in this context is Instrumentation, Protection & Control network, Level 2 automation is SCADA and Level 3 automation is integrated OMS/DMS (Integrated Outage/Distribution Management System).