Power Networks hexagon
Q-Flex innovation project


National Grid Electricity Distribution (NGED) is the largest distribution network operator (DNO) in the United Kingdom. As such, they are responsible for the reliable, safe and sustainable delivery of power to millions of homes and businesses.

Recently, NGED has been interested in the approach of reactive power flexibility to help strengthen its network. Currently, the amount of renewable penetration in all electrical networks is greatly increasing, leading to more instability due to weather fluctuations, etc. It has been theorized that reactive power dispatch from this distributed renewable generation can help stabilize the network and offer further benefits such as reducing losses.

The Q-Flex project, funded under Ofgem’s Network Innovation Allowance, aims to demonstrate if flexible reactive power is a solution for forecasted network constraints. NGED engaged PSC to investigate this possibility by optimizing actual network models and analyzing the benefits thereafter.


As the UK moves away from burning fossil fuels and towards renewables for generating electricity, the expected load in many regions is likely to increase. This is due to an increasing reliance on electricity to power heat pumps and charge electric vehicles, for example.

With the increase in low-carbon technologies (like wind and solar) connected to the electrical network, the grid is more subject to changes in weather. For example, during winter, when there is maximum load and less solar power available, a network may have voltage and thermal constraints if a fault appears. Traditionally, this may have been corrected through costly network reinforcements such as new HV  transmission lines.

This innovation project aimed to show how reactive power flexibility could be used instead, especially where certain generators, such as some solar inverters, have the ability to produce reactive power even without sunlight.

Project Solution

PSC investigated the application and benefits of reactive power flexibility to distribution networks via five distinct work packages. 

  • Work Package 1 – This work package involved investigating and analyzing current and emerging reactive power technologies.
    OUTCOME: A catalog of reactive power capabilities.
  • Work Package 2 – This work package involved the adaptation of a previous PSC algorithm to use particle swarm optimization to determine reactive power setpoints in NGED network models at the 11 to 132 kV level to delay network reinforcements and reduce losses.
    OUTCOME: The successful algorithm showed that some reinforcements could be delayed, and certain losses could be reduced.
  • Work Package 3 – This work package used the results of WP2 as well as inputs and guidance from NGED to perform a costbenefit
    analysis of the use of optimal reactive power dispatch.
    OUTCOME: A cost-benefit analysis that proved a benefit could be achieved when considering the delay of network reinforcements but not through loss reduction.
  • Work Package 4 – This work package was performed by NERA, not by PSC. It involved a market design around reactive power
    procurement from technology asset owners. 
    OUTCOME: Reative power flexibility market design and assessment of interest from providers.
  • Work Package 5 – This work package involved a summary of all other work packages.
    OUTCOME: A complete report detailing learnings and recommendations.

PSC Advantage

PSC is a specialist company that is able to work with complex scopes and new technologies and ideas to produce usable results.
In particular, for this project, PSC has strong technical knowledge in electrical engineering as well as vast experience in software
development and data science techniques. These capabilities were combined to execute the Q-Flex innovation project, with many challenges overcome by the PSC team.

In addition, PSC also has significant market experience and knowledge, which was necessary to perform the cost-benefit analysis. This combination of knowledge of all areas of the energy sector enabled us to deliver a complex innovation project on time and with good usable results.


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