Electrical engineering
for high voltage
power systems

Independent electrical engineering, from study to energisation — for industry, renewable developers and infrastructure operators, in France and worldwide.

Get in touch Our services
HV substation — circuit breakers and current transformers, LDHT Engineering site work

HV substation — site work & studies on high voltage networks

Services

Our activities

A full range of services supporting your projects, from design through to operation.

Studies & Calculations

Full network modelling in ETAP and PowerFactory with standardised deliverables.

  • Load flow & power balance
  • Short-circuit & equipment withstand
  • Selectivity & protection scheme
  • Harmonic analysis & reactive compensation
  • Arc flash & PPE definition
  • Earthing systems — step & touch voltages
  • Motor starting & transient studies
  • Cable & transformer sizing
  • RTE grid connection files
Owner's Engineering & Advisory

Technical assistance to project owners across the whole project lifecycle.

  • Network architecture definition
  • Specification review / study validation
  • Tendering & contractor consultation support
  • Design review of execution studies
  • FAT / SAT / Commissioning
  • RTE / ENEDIS grid connection
  • Drafting of operating procedures
Audits & Expertise

Technical audits, judicial expertise and due diligence for your electrical assets.

  • Safety of people & assets
  • Technical due diligence
  • Asset ageing & maintenance condition
  • Performance optimisation
  • Lightning risk analysis
  • Judicial expertise & litigation support
Testing & Commissioning

Testing and commissioning of all network equipment — protections, cables, transformers, switchgear, rotating machines.

  • Protection relay testing & settings
  • Relay programming — ABB, Schneider, Siemens, GE
  • MV cables — VLF, tan delta, PD
  • Transformers — ratio, tan delta, SFRA
  • Circuit breakers & switchgear — contact resistance, thermography
  • Rotating machines — PI / DAR
  • Power quality analysis & disturbance recording
Renewable Energies

Grid connection studies and grid code compliance for PV, wind and BESS plants.

  • P/Q & U/Q capability diagrams
  • Grid code studies
  • DC networks — load flow, arc flash
  • RTE / ENEDIS grid connection
Training

Tailored training for your operation and maintenance teams.

  • ETAP & PowerFactory training
  • Arc flash / PPE awareness
  • Operational training tailored to your installations
Resources

Software & test equipment

In-house simulation and measurement resources, for reliable results and autonomous site work.

Simulation & calculation software

ETAP Network modelling and simulation — load flow, short-circuit, selectivity, arc flash, harmonics, earthing systems.
PowerFactory Network studies and grid code compliance for renewable connections.
ELEC CALC & CANECO Standardised LV / MV sizing and calculation notes.
AutoCAD Single-line diagrams, layout and earthing system drawings.
Python Calculation automation and results post-processing.
ABB PCM600 Settings and configuration of ABB protection relays.
Siemens DIGSI 4/5 Settings of SIPROTEC 4 and 5 relays.
Schneider Easergy Studio · SFT 2841/48 Settings of Schneider protections — Easergy and Sepam (SFT 2848 for the 48 series).
GE MiCOM S1 Agile Settings of MiCOM relays — including the Agile P14D range.

Measurement & test equipment

Protection relay testing on site — injection test set connected to a control cabinet
HEXAN 2 Three-phase secondary injection test set — protection relay testing and settings.
MG 40N MK2 Primary injection test set — protection chain testing at real current.
FLUKE 1775 Power quality analyser — measurements, disturbance recording and on-site campaigns.
METREL Soil resistivity, step and touch voltage measurements — earthing system validation.
MEGGER MOM2 Micro-ohmmeter — contact resistance measurement (circuit breakers, disconnectors, joints).
HIKVISION M30 Thermal camera — hot-spot detection on installations in service.
10 kV insulation tester HV equipment insulation testing — polarization index, DAR.
References

Clients & projects

Trusted by demanding clients, from major industrial groups to infrastructure funds.

Major construction groupElectrical contracting
Transformer specialistHV maintenance
International consulting firmEngineering consultancy
Infrastructure operatorEvents & venues
Renewable developerSolar & wind
Project integratorPV projects, Africa
Renewable developerOffshore & onshore wind
Infrastructure fundGreen energy
Selected assignments
Renewable developer — France
PV plant connected to an industrial MV loop

Full harmonic study — network modelling, distortion analysis across several operating scenarios, resonance risk assessment and transformer derating.

Project integrator — West Africa
9 MWp PV plant, 30 kV network

LV / HV / DC arc flash and earthing study — incident energy calculations, PPE definition per work location, earthing grid sizing.

Datacenter operator — France
Owner's engineering, 225 kV GIS substation — critical infrastructure

Technical support for the design review of a high-voltage GIS substation serving datacenter & AI infrastructure — document review, project compliance, review of design and execution studies, site follow-up.

General contractor — France
Protection scheme for a datacenter supplied at 240 MVA

Complete design of the protection chain for a very high power site — protection philosophy and functions, CT sizing, settings calculation, then commissioning follow-up through to energisation.

Project developer — BESS
HV / MV substation design for battery storage

Complete substation engineering — sizing of transformers, switchgear, cables, protections and earthing — tender documents, contractor selection support and project follow-up through to delivery.

Sample deliverables — anonymised
13.8 kV MV single-line diagram — protection scheme

Protection scheme — 13.8 kV MV single-line diagram

Time-current curves — selectivity study in ETAP

Selectivity study — time-current curves (ETAP)

3D potential profile — earthing system study

Earthing system — potential profile & step voltages

About

Léo Delaunay — Founder

LDHT Engineering is an independent power system studies and advisory practice, founded by Léo Delaunay, with over 15 years of experience spanning field work, engineering studies and profit-centre management.

A career built within major inspection and engineering groups, from regulatory inspection to the supervision of HV / MV / LV studies on major projects.

High voltage studies
Delivery and supervision of studies on projects up to €15M: selectivity, load flow, arc flash, earthing systems, grid connection.
On-site expertise & measurement
Power transformer, MV cable and rotating machine diagnostics, protection relay testing, power quality analysis, inspections and audits of industrial installations, in mainland France and overseas.
Advisory, audit & due diligence
Technical due diligence, techno-economic analysis with an OPEX / CAPEX perspective, asset ageing and obsolescence assessment, technical advisory in judicial expertise proceedings — reporting to boards and executive management.
Project & team leadership
Management of profit centres up to €2.5M revenue and 24 staff, national responsibility for high voltage business development, tendering, technical proposals, site follow-up and commissioning.

Education & qualifications

Executive Master — General Management
EM Lyon Business School — 2023
Advanced Technician Diploma (BTS) — Electrical Engineering
Lycée Joliot Curie — Rennes, France
ETAP PowerFactory ELEC CALC CANECO Python

Sectors served

  • Industry & Oil and Gas
  • Datacenters & AI infrastructure
  • Renewables — PV, wind, BESS
  • Large commercial & event venues
  • Transmission & distribution networks
Contact

Let's talk about your project

Contact details

Monday to Friday (CET)
Reply within 24 business hours
Based in France
Projects across France & worldwide
LinkedIn — Léo Delaunay
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