GRIDSERVE Electric Vehicle Forecourts

About GRIDSERVE

GRIDSERVE is the market leader in electric vehicle charging stations.

Our brief was to support GRIDSERVE as part of the company’s commitment to delivering more than 100 Electric Forecourts within this decade in line with the government’s goal of net-zero by 2050. Several additional Electric Forecourt sites now have planning permission including Uckfield, Gateshead, and Conesby, with more than 30 additional sites also in development. All sites include a range of charging units such as ABB and Tesla.

Also ensure that sites are powered in the safest, most reliable, and efficient way, providing a widespread but ever-expanding network of charging stations.

Customer Challenge

To create the most energy-efficient and sustainable power systems for vehicle charging units, allowing the units to support the Net Zero strategy. To create assessments for every plant that will meet the most up-to-date Electrical Networks Associate (ENA) standards in order to get approval for connection from the Distribution Network Operator (DNO). One of these standards is the Engineering Recommendation P28, under which a number of various technical conditions of the plant under consideration, are assessed against the appropriate limits set in the standard. One of the most important quality measures of the new connection is determined by the voltage fluctuations it can cause to the DNO’s network.

Example

Due to the number of transformers present in the Norwich East EV Forecourt and the nature of the network where it was being connected, the magnetising inrush currents produced during the simultaneous re-energization of all existing transformers would cause severe rapid voltage distortion (RVC). Therefore, breaching the statutory limits defined in EREC P28. Find out more about transformer inrush here.

PSE2 Solution

In partnership with the client (GRIDSERVE), different strategies were suggested. PSE2 proposed a solution that depended on the plant's ability to energise the transformers sequentially. Several simulation scenarios were evaluated using PowerFactory to find a solution that would satisfy the criteria required by the DNO and that was also viable from the customer's side.

Different transformer energisation strategies were evaluated in order to guarantee Norwich East was compliant with the voltage distortion limits enforced in EREC P28.

This included introducing a more complicated hybrid power solution; mixing solar energy and battery power. This creates more efficient power systems because solar energy is only accessible during daylight hours, and is less powerful in the winter months, which can make it difficult to use on its own. By creating a hybrid power system, our team was able to collect the solar energy and store it in the battery system making it available to power the charging units when it is needed, not just when the sun is shining.

Once the switching strategy was in place, the maximum voltage change caused by the inrush currents during the transformer’s energization was alleviated and the voltage distortions kept within the required limits.

Find out more about our Grid Connection Services.