What is a ‘Smart Grid’?
A traditional grid consists of mainly passive or stand-alone elements like conductors, insulators, switches, transformers, fuses etc. These elements have limited capability to communicate their state.
The Smart Grid incorporates active, communicating infrastructure which is not only self-aware but situationally aware of surrounding devices and their status. Smart Grid devices are monitored, controlled and in some cases automated to perform specific tasks that optimize energy use, maintain reliability and service quality.
The emergence of the ‘Smart Grid’
The distribution grid in Ontario (and North America) has been slow to adopt modern technology. In October 2009 US President Barack Obama announced a $3.4 billion investment to fund modernization of the electricity grid. The Smart Grid was kick started. The primary driver is the widespread implementation of renewable generation at the distribution level.
In 2009 the Ontario government announced the allocation of $50 million over 5 years for Smart Grid. In 2011 the Ontario Energy Board initiated a consultation process (EB-2011-0004) intended to help the Board better understand the technical issues and identify the need for policies to manage them. The OEB created a Smart Grid Advisory Committee in 2013 to provide ongoing assistance at the regulatory level.
The Ontario government has continued the Smart Grid Fund for innovators to develop cutting edge technologies. Investments now total $200 million for 45 projects. According to the government over 800 high-tech jobs have been created in Ontario.
A list of funded projects in Ontario is available on the ontario.ca website.
The Canadian government is also active in sponsorship of the Smart Grid through Natural Resources Canada (NRC). In 2018 NRC initiated a program with funding of up to $100 million for qualified proposals.
Why does anyone need a ‘Smart Grid’?
A ‘Smart Grid’ is essential to manage the increased complexity of grid architecture, renewable distributed generation, transportation electrification, energy storage, load management, conservation, microgrids, reliability, and customer expectations. There are many more drivers for Smart Grid and I have only highlighted a few.
At the most basic level, a utility must implement ‘smarter’ infrastructure in order to integrate the large number of distributed renewable generators that are appearing on the landscape. Without the upgrade, power quality and reliability will plummet. The addition of generators at random locations in the distribution system creates capacity, voltage regulation and protection coordination challenges for the distributor.
The local distributor is obligated by license to maintain the customer voltage within 6% of the rated value of the service. With the introduction of multiple new generators, voltage regulation becomes a significant challenge as it swings up and down with different power flows. When voltage swings exceed the allowable range, some devices automatically disconnect (trip) from the system. All of this creates a dynamic challenge that legacy devices were never intended to manage.
The distributor must also manage the capacity limitations of their infrastructure. With the addition of generation on the system the power flows change with different contingencies and capacity upgrades may appear necessary. In a first-pass capacity calculation you would anticipate sizing the system for the worst-case of maximum generator output on top of the worst-case load. Under this criteria the numbers may trigger a capacity upgrade on the system. Without any form of monitoring or control it would be the prudent thing to do.
In reality, the maximum generator output from a renewable is not likely to occur at the same time as the worst-case load criteria. Nor are maximum outputs from renewables such as wind and solar likely to occur at the same time. In a Smart Grid you have the monitoring and control in place to manage the grid resources to remain within the limitations of the existing infrastructure for the rare contingencies that may occur and overload the system. If it is less costly to make the grid ‘smart’ than to increase infrastructure capacity – you implement the smartest option.
The protection systems that ensure instantaneous clearing of faults during disturbances are impacted by the addition of generators. The protection devices require additional capability that will – without question – trigger a ‘smart’ upgrade.
It remains for the industry to demonstrate the feasibility of the advanced capability and perform the necessary cost-benefit analysis to move forward with widespread implementation.
Energy Efficiency
In a perfect world, the electricity infrastructure would have 100% utilization. That means our system is not too big, not too small, but just right. Demand would never increase or decrease over time and we would have a steady state environment.
The reality is that energy demand changes throughout the day as people and businesses get on with their lives. It changes by season and time and as a result of economic forces. Equipment has to be removed from service for maintenance or failure and power flows change according to the contingencies.
As a result the infrastructure is oversized to accomodate the peak load, seasonal fluctuation, life cycle load growth and abnormal operating modes. All of these factors contribute to a reduced utilization factor and lower efficiency.
Here is what the Toronto load looks like for November 12, 2018:
The Smart Grid can provide the tools to reduce peak demand and improve the efficiency of the distribution infrastructure. In some cases it may help avoid upgrades due to peak capacity growth.
Some of the tools include energy storage, smart meters and conservation mechanisms at homes or businesses.
Comparing ‘Smart’ to ‘Traditional’ grid performance
| Problem – loss of power to customers. | Traditional Electricity Distribution | The Smart Grid |
| Blown fuse | Customer contacts the distribution company to report the outage.
The distributor rolls a truck to the customer location and performs an inspection. Locates the source of the interruption by patrolling the line, determines the cause and takes corrective action. Replaces the fuse on completion to restore customers. |
Smart Meters send outage alert to the distribution company operating center. Operator determines the location of the fuse based on outage pattern and dispatches crew to specific location with proper fuse replacement. Crew begins line patrol from the fuse and performs repairs as in the traditional case. |
| Circuit breaker trip (recloser) | Customer contacts the distribution company to report the outage.
The distributor rolls a truck to the customer location and performs an inspection. Crew begins line patrol from the customer premise, locates the source of the interruption, determines the cause and takes corrective action. Resets and closes the circuit breaker to restore customers |
The circuit breaker and smart meters send outage alerts to the distribution company operating center. The circuit breaker also communicates the wire (phase) with the problem and the distance from the circuit breaker location.
The distributor rolls a truck to the predicted fault location as directed by the operating center to fix the problem. Upon completion the repair crew informs the operating center to close the breaker remotely to restore customers. |
In the specific cases outlined, the difference in response and restoration times can be substantial.
In the traditional case the distributor knows nothing about the status of customer supply unless the customer complains. Once informed of the supply problem the service crew must be dispatched with little information on the outage cause or location. The crew locates the problem by visual inspection of a distribution system that may be many kilometers in length with a mix of overhead and underground infrastructure.
In the Smart Grid case, notification to the distribution company is immediate. The extent of the outage is known and the fault location identified. Proactive social media updates are posted. A crew is dispatched knowing where to begin inspection and the location of the isolating device. The outage duration should be substantially reduced over the traditional grid case.
There are hundreds of cases where the Smart Grid offers performance advantages over the traditional infrastructure.
I have barely scratched the surface on the subject of Smart Grid but this should provide readers with a basic high-level understanding of it. You should contact your Local Distribution Company to find out what initiatives they have underway and how they may be of benefit.
The takeaway…
The changing of the electricity infrastructure is driving the need for modern devices with advanced functionality to be implemented by utilities. It is an evolutionary process. Like it or not, the world is moving forward.
Don’t be left behind.
If we don’t have a Smart Grid… what do we have?
Derek
Next article… Smart Meters
