At RenSolv, we are specialists in performing EREC P28 voltage fluctuations compliance assessment studies. Our engineers have been delivering power quality and grid compliance studies for over 15 years across solar, wind, BESS, conventional generation, and co-located projects, supporting developers and asset owners to progress grid connections with minimum delay.
EREC P28 is the UK engineering recommendation used to assess voltage fluctuations caused by disturbing equipment connected to transmission and distribution networks. For renewable and storage projects, it is particularly relevant because it addresses the practical power quality risks that can arise during energisation, switching, tripping, and normal inverter operation.
A P28 assessment is not simply a documentation requirement. It is intended to demonstrate that the project can be connected and operated without creating unacceptable voltage disturbances for other network users.
In practice, P28 compliance assessments commonly focus on:
These items are often key approval gates because they directly influence how a site is commissioned and how it will be operated on the network.
We keep our clients informed throughout the assessment process. If a potential non-compliance is identified, we raise it early so it can be resolved before documentation is finalised. This saves time, avoids unnecessary iteration, and allows practical operational solutions to be agreed early.
That might include, for example, pre-insertion resistors, point-on-wave switching, or revised energisation sequencing. We aim to make P28 outcomes useful not only for the DNO submission, but also for commissioning and long-term operational planning.
A robust P28 submission is designed to provide clear evidence covering:
RenSolv provides professionally written technical reports authored by specialist power system engineers with extensive power systems backgrounds and years of technical experience on real projects.
Our reports provide a clear, structured submission for both the client and the DNO, presenting compliance outcomes against the relevant requirements and limits, with unambiguous conclusions and practical next steps where required.
RenSolv provides P28 compliance assessment studies for a wide range of generation and storage developments, including:
Our studies support projects connecting at distribution voltages including 11 kV, 33 kV, 66 kV, and 132 kV.
As a recent example, we performed a P28 compliance assessment for a facility consisting of a solar farm and a BESS connected first to an independent DNO at 33 kV, and then to the DNO network at 132 kV via a 52 MVA 132/33 kV grid transformer.
The overall site had a maximum export capacity of 42.7 MW and an import capacity of 10 MW, consistent with the connection agreement, and the P28 scope covered transformer energisation impacts, voltage step changes, and flicker emissions for both the solar farm and the BESS.
RenSolv engineers have supported renewable generation and energy storage projects across the UK transmission and distribution networks.
Further details on comparable projects supported by RenSolv can be found in our Project Experience section.
We bring specialist power systems expertise backed by years of industry experience in power quality compliance. Our submissions are structured around the evidence that network operators expect to see, helping minimise unnecessary review cycles.
We work with clients to identify issues early, translate them into realistic commissioning and operational actions, and keep the compliance process both technically clear and commercially usable.
Where required, we attend meetings with project teams and network operators to support the project through to completion, helping close out technical queries beyond the study report itself.
Book your free 30-minute consultation today.