Substation Monitoring for Future Networks

Substations perform a fundamental role in modern power grids. The optimal voltage for long-distance transmission is much higher than the voltage used for distribution to end customers, and substations convert electric power between these voltage levels. However, substations themselves also consume large amounts of energy: even the most efficient transformers experience power losses, and the complementary equipment that keeps adequate operating conditions has a significant energy footprint as well.

The energy usage of substations is unique because it can be metered but not billed – the grid operator would be billing themselves! Thus, this operating expense can only be addressed by minimising substation power consumption.

• Some power losses are unavoidable and uncontrollable. For example, transformer load is determined by power demand, so there is no way to eliminate transformer losses completely. Aging units can be replaced with newer and more efficient ones, but the associated capital expenditures are significant.

• Complementary substation systems like lighting, space heating, equipment cooling and oil pumps allow a greater degree of control. Their operating parameters can be adjusted based on power grid load and environmental conditions.

SSE have already deployed IoT appliances successfully in many of their projects: for example, through the RealValue project, they are deploying smart heaters with hot water storage across multiple households, using smart data to manage their operation and achieve a significant reduction of power grid operating expenses. Now, SSE Future Networks are analysing the feasibility of a similar concept at their substations, to minimise non-technical losses.

Energy Monitoring: The First Step for a High-Efficiency Substation

Power substations have the same mechanical and electrical systems that are common to most buildings: lighting fixtures, space heating and air conditioning. They also include application-specific equipment such as transformer oil pumps, battery chargers, dehumidifiers and air compressors.

As previously mentioned, energy conversion losses are impossible to control directly, and the only viable approach is to replace existing transformers with modern and more efficient units, a topic that falls outside the scope of this article. Other building systems can be configured according to operating and environmental conditions, but keeping substations permanently manned with dedicated staff would prove unfeasible and very expensive, possibly negating the operating savings achieved. A smarter alternative is using information technology to monitor these complementary substation systems, possibly making them autonomous to a degree.

Advantages of Granular Monitoring in Electrical Substations

Before deploying a monitoring solution for complementary substation systems, there is key question to answer: what is the required level of detail and granularity? The simplest approach would be to monitor overall consumption, while the most sophisticated solution is monitoring each substation system individually. The first solution is less expensive and faster to install, but the second provides greater insight to reduce energy consumption.

General monitoring provides a baseline to compare future upgrades, but energy audits are then required to assess the feasibility of specific measures. On the other hand, granular monitoring completes the first part of the energy audit automatically and continuously – gathering data. Consider there are also larger substations composed of multiple buildings, where detailed measurements can be of great help when planning and prioritising upgrades.

How Operation and Maintenance are Simplified in a Managed Substation

If complementary substation systems are only configured during initial construction and routine maintenance, performance issues can arise over time. For example, lighting and HVAC operation can be wasteful at times, just like there can be cases when these systems operate below the required output, compromising the integrity of another substation equipment.

Keeping all substations in a network fully staffed with maintenance personnel 24/7 is impractical and very expensive. However, a substation with building management technology provides many advantages in terms of operation and maintenance:

• Proactive Maintenance: Utilities can leave behind the conventional maintenance approach, which is routinely and reactive. A managed substation allows proactive maintenance, which consumes less man-hours and materials, while minimising downtime. Instead of waiting for components to break down, issues are solved as soon as they start giving warning signs. Consider the consequences of allowing a fault to occur in a substation – depending on the severity, large portions of a grid may be left without power.

• Smart inspection: A building management system can make inspection tasks remote or even automated, saving man-hours and fuel otherwise used on site visits. Even reporting functions can be automated, saving even more time for utility company staff.

• Enhanced safety: If a building management system is deployed for a substation, on-site staff presence is required less frequently, and the system gives warnings when dangerous conditions are detected. Potentially dangerous surprises are prevented during inspection and troubleshooting.

• Optimised upgrades: The data provided by a building management system reveals the most promising substation upgrades. Once deployed, the same system provides new data to assess the effectiveness of upgrades, through comparison with previous data.

To summarise, a building management system can help network operators understand their substations better. Every building is unique, and this applies even for substations in a power network – electricity demand profiles and weather conditions are different for each facility, even if their main function is the same. Logic Energy building management solutions come with a customisable platform that adapts to the needs of any facility, and our technology has been deployed successfully across various business sectors for more than a decade.

A final note: Modern power systems are more demanding for substation infrastructure, with the rise of variable generation systems like solar photovoltaic arrays and wind turbines. With these technologies, there is now variability in both supply and consumption, and many energy consumers have also become small-scale generators. Substation infrastructure must adapt to the needs of the modern power grid, and building management systems can be of great help towards this goal.