What is Active Network Management (ANM)?

Active Network Management (ANM) is a subject that you are going to hear a lot more about if you are involved in the installation, development & / or planning of distributed generation and / or energy storage projects.

As the magnitude & complexity of energy flows across the electrical Grid increases, there is a requirement by the Distribution Network Operators (DNOs) and the Transmission Network Operator (TNO) to ensure that the physical and safe limits of the network are maintained.

When energy flowed in a single direction between major power stations and business / homes, this was relatively easy (compared to today) because the bi-directional flows were limited to a few trailblazers putting solar / wind on their properties / land.

Now, with the huge investment undertaken over the last 15 years in solar, wind and, more latterly, energy storage, the need to manage power flows to ensure physical limits are protected is more acute.

Active Network Management (ANM) is the catch-all term for the solution to this and can be split into Distribution Active Network Management (DANM) and Transmission Active Network Management (TANM).

Distribution Active Network Management (DANM) is the management of power flows by the distribution operators – so in the UK that would include the likes of Western Power Distribution (WPD), UK Power Networks (UKPN), Electricity North West (ENW), Northern Power Grid (NPG), Scottish & Southern Energy (SSE) and Scottish Power Energy Networks (SPEN).

Transmission Active Management and Constraint Panel Interfaces

Transmission Active Network Management (TANM) is the management of power flows by the Transmission operator, that would be National Grid in the UK.

The typical Transmission Active Network Management (TANM) interface is called a Constraints Panel (CP) although we’ve found multiple different names / acronyms used (however, “Constraint” is in all the titles) and is located within the client’s local sub-station.

Constraint Panels (CP) typically have 2 stages. Stage 1 is a transmission-led activation signal to ask the generator to cap their output to a percentage value of their maximum output which we have typically found to be either 0% or 30%. If stage 2 is activated then this requires the generator to trip their main breaker (to the generation, not the whole site.) These stage 1 & stage 2 signals are related to Grid stress at the transmission level yet communicated locally via the interface equipment.

In a way, Transmission Active Network Management (TANM) is a blunt tool to solve a complex, sensitive problem.

Distribution Active Management and Dynamic Control

However, to some extent, the sensitivity of control is managed by the Distribution Active Network Management (DANM) level (which I will now just refer to as Active Network Management).

At this level, Active Network Management (ANM) is looking to dynamically monitor the overall power flows on the local network and then allocate power within the local physical limits to the different generators using the Last-In First-Out (LIFO) principle.

In other words, if at a moment in time there is only 100 Mega Watts (MW) of available generation power headroom and 2 generators in the LIFO stack (1st has 60MW and the 2nd has 50MW) then the 1st will be allocated all their potential generation, whilst the 2nd will only be allocated 40MW of their 50MW.

This constantly appraised value is dynamically communicated to each local site which has an Active Network Management (ANM) connection offer with 2-way communication to confirm receipt of the updated value and clarification that the generation value is within the limit.

New protocols are emerging all the time, yet the preferred communication language between the ANM interface and the generator is DNP3. Because most generators do not “speak” DNP3, this requires (typically) an independent interface to translate the communication between the DNO Active Network Management (ANM) interface and the client generation manager.

This, for example, is where GridGEM (see https://www.argandsolutions.com/gridgem-control-and-monitoring-for-renewables-and-energy-storage) is starting to be used – acting as the client interface to ensure the required control actions are undertaken and translating all of the actions between both parties.

Critical within all Active Network Management (ANM) installations is the requirement for everything to be “fail-safe” so if any communication channel fails then the system will automatically switch off the generation asset.

Although I referred to power in the brief example above, Active Network Management (ANM) does not just focus on power (kW). It is also able to regulate reactive power (kVAR) which is related to power factor and voltage.

However, it should be noted that currently (2022) most DNOs are just managing power dynamically in their Active Network Management (ANM) connections with reactive power and voltage embedded for future use. Even more so, typically for smaller sites, active power is managed relative to a fixed export limit as opposed to a dynamically changing value.

Active Network Management (ANM) - Into the Future

As with all these things, the dynamic nature will merge over time, yet the foundations have been put in place and we need to be ready.

As we’ve discussed above, Active Network Management (ANM) is currently managed across the 2 Grid system areas (distribution & transmission), however going forward we expect the DANM & TANM to merge into a single “Super Grid” system whereby all distributed generation and energy storage will have a DNP3 type interface to accept a single network management signal giving a holistic approach from transmission all the way down to localised distribution levels.

Therefore, the need to have this more complex interface will become ever more important.

I hope you’ve found this useful and if you need more information then please get in touch at either bepositive@argandsolutions.com or call +44-1803-864706.

Thanks.

Fraser Durham

Commercial Director