PowersystemstudiesforUKgridconnections
G99, Grid Code, P28, G5 and protection coordination studies for generators, battery storage and industrial loads, modelled in DIgSILENT PowerFactory by the engineers who also build and commission the hardware.
- Modelling
- DIgSILENT PowerFactory
- Scope
- Type A–D generators & BESS
- Deliverables
- Electronic, DNO-ready
- Coverage
- UK, EU & North America
The study is the long pole in the schedule.
Most grid connection programs do not slip because equipment is late. They slip because a study came back inconsistent with the network operator's model, or because protection settings could not be graded against an upstream device nobody had data for. By the time that surfaces, the connection window has moved.
We work the other way round. Our engineers build the network model first, run the compliance cases the operator will run, and hand over a study pack that answers the questions before they are asked. Where an assumption has to be made, it is stated on the page, so the reviewer can accept it or challenge it without a round trip.
Because we also design, build and commission the hardware, the study is not an abstract exercise. A sizing recommendation from our consultancy team is one our engineering team has to deliver against.
The studies your DNO or TO will ask for
Studies are scoped per project. The list below reflects the work we run most often for generation, storage and industrial connections.
Power system studies
Load flow, fault level assessment, reactive power capability analysis and loss assessment across transformers and cables, for Type B and Type C/D generators and storage.
Protection coordination
HV, MV and LV protection functions graded end to end, covering time-graded and unit protection schemes, with settings tables issued in the operator's format.
G99 & Grid Code simulation
Dynamic simulation for generators and BESS using validated inverter and PPC manufacturer models, with or without power quality capability assessment.
Power quality: P28 and G5
Stage 2 and Stage 3 G5 harmonic assessments and P28 voltage fluctuation studies, including dynamic flicker response for BESS in DM, DR and DC frequency response modes.
Insulation coordination
Surge arrester sizing calculations, and full electromagnetic transient (EMT) modelled studies where switching or lightning transients drive the design.
Cable & thermal rating
HV/MV cable rating assessment and LV AC and DC cable calculations, sized against real installation conditions rather than nameplate tables.
Feasibility & sizing
Right-sizing UPS, BESS, STATCOM and capacitor bank solutions against the actual operating objective: peak shaving, frequency response, power factor penalty avoidance or ride-through.
Arc flash & safety studies
Incident energy analysis and labelling to support safe working practice and code compliance across industrial and utility switchgear.
Studies written by engineers who have to deliver them
A sizing recommendation or a protection setting from our study team is one our field engineers go on to install, test and commission. That is why the assumptions are stated on the page, and why the settings tables are issued in a form an engineer on site can use.
How we work
Method
- Simulation software
- DIgSILENT PowerFactory, for Grid Code, G99 and EMT studies
- Inverter & PPC models
- Validated manufacturer models, supplied per project
- Harmonic inputs
- Equipment emissions, network harmonic impedance and background data provided by the network operator
- Deliverables
- Electronic study report, model files and settings tables
Typical study set: generation and storage
- Power system study
- Type B and Type C/D
- Protection coordination study
- Type B and Type C/D
- G99 simulation studies
- Type B and Type C/D, generator or BESS
- Grid Code simulation studies
- Generator or BESS
- P28
- Standard and dynamic flicker response assessment
- G5
- Stage 2 and Stage 3
- Insulation coordination
- Arrester sizing or EMT modelled
- Cable rating
- HV/MV assessment, LV AC & DC calculations
Study prices are quoted per project against a defined scope. Contact us with your single-line diagram and connection offer for a fixed-price proposal.
Where our studies get used.
- Grid connection applications for solar, wind and hydro
- BESS connection and compliance packages
- Industrial load connections and capacity upgrades
- Private wire and dual-connection arrangements
- Retrofit and expansion of existing substations
- Due diligence on acquired generation assets
Installed and supported across UK wind and grid sites
The same group designs, installs and maintains reactive power and power quality equipment at wind farms and grid connection sites across the UK.
When the study calls for equipment
Consultancy is a standalone service, and much of our study work is for projects supplied by others. Where the answer is hardware, the group engineers, installs and supports it too.
GridLink Private Wire
A controlled converter interface that sells local generation directly to local demand, islanded or grid-parallel, built to the capacity the project requires with a G99 fault-ride-through variant.
Read moreENERGY STORAGEBESS
Grid-forming storage customised to any size, with standard configurations from 365 kWh cabinets to 50 MWh medium-voltage blocks. Cascaded topology, liquid cooled, sub-5 ms response, no station transformer.
Read moreREACTIVE POWERSTATCOM & SVG
Three-level IGBT STATCOM and MV SVG customised to any size, with standard platforms to ±3600 kvar per system and 6–55 kV. Response from 5 ms, with fault ride-through, harmonic and negative sequence compensation.
Read moreUPS SYSTEMSUPS Systems
Modular low-voltage UPS from 50 kW to 4.8 MW, and medium-voltage PureWave UPS to 22.5 MW at 5–25 kV. Both protect the whole facility, not one row of racks.
Read moreFIELD SERVICESField Services
Commissioning, FAT/SAT, preventive maintenance, repairs and refurbishment, including legacy PureWave and DSTATCOM fleets the original manufacturer no longer supports.
Read moreOne group, two names.
Severn Drives & Energy is the UK company behind Renewable Energy & Drives. Whether you know us as Severn in the UK or as RE&D in North America, you are dealing with the same engineers, the same product range and the same service organisation.
Severn Drives & Energy was founded by Jonathan Jones and Damian Critchley as a renewables-focused offshoot of the Severn Glocon Group, the Gloucestershire engineering group known for critical control valves in oil and gas. It built its name repairing and maintaining power electronics on UK and Irish wind farms for operators including EDF, Scottish Power and SSE.
In 2023 the group acquired S&C's Global Power Quality Service Business, bringing a manufacturing and service facility in New Berlin, Wisconsin, a North American field service team, and ownership of the PureWave UPS, UPS XT and DSTATCOM designs.
Severn Drives & Energy
Questions we get asked most.
- What software do you use for Grid Code and G99 studies?
- All Grid Code and G99 dynamic simulation studies are carried out in DIgSILENT PowerFactory, using validated models supplied by the inverter or power plant controller manufacturer. Electromagnetic transient (EMT) studies are modelled in PowerFactory as well.
- What is included in a power system study?
- A standard power system study covers load flow analysis, reactive power capability analysis, fault level assessment and a loss assessment across transformers and cables. Protection coordination is quoted separately and covers HV, MV and LV protection functions including time-graded and unit protection.
- What is a dynamic flicker response assessment?
- It is an extension of a P28 study that considers flicker resulting from system frequency variation when a BESS is operating in Dynamic Moderated, Dynamic Regulation and Dynamic Containment frequency response modes. It is currently an NGED requirement rather than a universal one.
- Can you take on a study another consultant started?
- Yes. We regularly pick up stalled connection applications, most often where a study has been rejected or where the original modeling assumptions no longer match the design. We will review what exists before quoting so you are not paying twice for the same work.
- Do you need to supply the equipment to do the study?
- No. Consultancy is offered as a standalone service and a large share of our study work is for projects where the equipment is being supplied by someone else. Where we do supply the hardware, the study and the delivery are covered by one point of contact.
- Is Severn Drives & Energy the same company as Renewable Energy & Drives?
- They are one group. Severn Drives & Energy Limited is the UK company, based in Kibworth Beauchamp, Leicestershire. Renewable Energy & Drives is its North American arm, formed in 2023 from the acquisition of S&C's Global Power Quality Service Business. Customers in the Americas are served by RE&D, and customers in the UK, Europe and the rest of the world by Severn.
- Where is Severn Drives & Energy based?
- Units 2 & 3, Kingsley Business Park, New Road, Kibworth Beauchamp, Leicestershire, LE8 0LE, United Kingdom. Telephone +44 116 279 6131, email sales@severnde.co.uk.
Send us the single-line diagram and the connection offer.
Study prices are quoted per project against a defined scope. Contact us with your single-line diagram and connection offer for a fixed-price proposal.
Let's Solve Your Power Challenge.
Connect with our engineering team for a technical consultation. We'll help you identify risks and uncover efficiency opportunities.
Renewable Energy & Drives
5325 S Moorland RdNew Berlin, WI 53151United States
Severn Drives & Energy
Units 2 & 3, Kingsley Business ParkNew Road, Kibworth BeauchampLeicestershire, LE8 0LEUnited Kingdom
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