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What exactly is power management?

With a power management system (PMS), power is matched with demand in your power system. Suitable for all applications on land or at sea, and for all types of power sources including renewables, PMSes automatically monitor and control your installation, ensuring uninterrupted power and allowing you to operate the installation as efficiently as possible.

If your power sources do not produce enough power, your operations could be jeopardised. Conversely, if they produce too much, you could be spending too much on power generation, for example on diesel fuel. Neither of these scenarios are acceptable, but you can avoid them using a power management system (PMS) which ensures that enough power is available with the right amount of power sources online. It controls your power sources and breakers as efficiently as possible, allowing you to save on operating costs.

Constant power delivery

A PMS constantly monitors your installation in order to detect if a power source becomes unstable or unavailable. If a blackout does occur, the PMS restores power to the installation as quickly as possible. If grid power disappears, for example, the PMS might immediately switch to a local UPS while cranking one or more gensets in order to ensure a steady power source until grid power becomes available again. The PMS ensures that the changeover from one power source to another goes as smoothly as possible, with a minimum of instability and interruptions in power delivery.

Load handling

The PMS can also carry out load sharing, for example in order to distribute the load between several gensets or photovoltaic panels. If power demand is approaching the maximum power generation capability of your installation, and it is not possible to activate extra power sources, for example on a ship at sea, the PMS may also be able to carry out load shedding, cutting out non-critical loads in order to lower power demand.


Caption: When at sea, ships occasionally need to lower power demand so that the load demand does not outstrip the available power. A power management system handles this automatically through load shedding based on predefined parameters
Image tags: ship, vessel, sea, load, load shedding, power management, PMS, DEIF

Suitable for renewables

PMS solutions are available for all types of power sources, for example grid power, gensets, battery storage, and renewables such as wind turbines and photovoltaic panels. You can combine one or more of these power sources in a solution that balances the need for consistently reliable and sufficient power with the important objective of using more sustainable and renewable power sources. With a PMS, you can contribute to a better climate while still getting optimal power management.

How does a PMS work?

In a PMS, the individual controllers controlling the power sources (grid connection, gensets, battery storage, and so on) and breakers are all interconnected in a communication network. The controllers constantly communicate over this network, exchanging information about the current load, their own power production capabilities, and the size of the current load on the power source they are controlling. Based on this information, the PMS calculates which power sources to use and how many power sources need to be active, and sends out commands as needed, for example to open and close breakers, crank gensets, and so on. Using information from the controllers, the PMS can also detect if one or more power sources are becoming unstable or unavailable, taking action to prevent a blackout as described above.

When running on gensets, a PMS will ensure that you only run the precise amount of gensets needed. This reflects the individual application. In critical applications, the PMS will normally run with all gensets on bus while facing a mains outage. In other, less critical applications, only the number of gensets necessary to ensure enough available power will be running. This reduces the fuel cost associated with running your gensets while also reducing maintenance costs for the gensets.

PMS benefits

A PMS gives you several important benefits:

  • consistently reliable and sufficient power
  • blackout prevention
  • resilience to single points of failure
  • reduced genset fuel consumption
  • predictive maintenance

More options with state-of-the-art PMSes

Modern PMSes with advanced technology often provide even more options that help you achieve efficient and economical operation. Here are a couple of examples:

  • With a good power management system, you get the option to run in automatic mode and thereby minimise the effort required for handling daily operation tasks. In normal operation, user interaction will normally not be required; indeed, automatic operation can reduce the risk of human error.
  • Modern PMSes often come equipped with user-friendly interfaces that give operators an easy overview of the current status and making it easy to make changes. This means that operator training is far easier, and it increases operator confidence in the PMS.
  • PMSes can be based on a multi-master architecture. This means that any one of the interlinked controllers can act as master controller, and that any other controller can take over the master role in case a controller goes offline. This increases the reliability in power systems. Controllers can be distributed control systems (DCSes) or programmable logic controllers (PLCs); which type to use depends on the capabilities, requirements, and setup of your organisation.
  • If you are using a building management system (BMS) or similar, a good PMS can interface with that system in order to control and monitor load distribution, backup power, and other important performance parameters.


Caption: The DEIF AGC-4 automatic genset controller is an example of an advanced controller that can form part of a multi-master PMS

In short, power management is the backbone of reliability, constantly monitoring and controlling power sources to ensure available power for the load point.

Security of supply with a DEIF PMS on an off-grid island with several renewables: read the case story 
Download our FREE whitepaper on the advantages of multi-master PMS solutions 
Contact DEIF power expert Morten Østergaard Fog to learn more about power management


About the author

Morten Østergaard Fog

Product Specialist

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