Power Projects Awarded Insulation Coordination Study for 400/220/33 kV Utility-Scale Solar Evacuation Network
Comprehensive assessment of transient overvoltages across an extra-high-voltage renewable energy evacuation system comprising multiple 500 MVA autotransformers and associated transmission infrastructure
Power Projects is pleased to announce the award of an Insulation Coordination Study for a utility-scale solar evacuation network operating at 400 kV, 220 kV and 33 kV voltage levels.
The engagement involves a comprehensive assessment of transient overvoltages across an extra-high-voltage renewable energy evacuation system comprising multiple 500 MVA autotransformers and associated transmission infrastructure.
As renewable energy projects continue to expand in scale and complexity, detailed insulation coordination studies are essential to ensure equipment reliability, optimise surge protection and support secure long-term network operation.
Using advanced electromagnetic transient simulations in PSCAD, Power Projects will evaluate equipment insulation performance under switching, lightning and fault-induced overvoltage conditions.
Comprehensive Assessment of Transient Overvoltages
The study encompasses a broad range of transient phenomena to verify insulation adequacy and surge protection performance throughout the network.
The scope includes:
Temporary Overvoltage Study
Slow Front Overvoltage Study
Fast Front Overvoltage Study
Very Fast Front Overvoltage Study
Transferred Surge Study
Transient Recovery Voltage Study
Assessment Coverage
- 400 kV transmission infrastructure
- 220 kV transmission infrastructure
- 33 kV collector network
- Five 500 MVA autotransformers
- Assessment of surge arrester requirements for 33 kV transformer incomer feeders
Why Insulation Coordination Matters
Extra-high-voltage renewable evacuation systems are routinely exposed to switching operations, lightning events, GIS transients and fault-related overvoltages.
Without effective insulation coordination:
- Equipment insulation may be overstressed
- Surge arresters may be incorrectly selected
- Transformer reliability may be compromised
- Flashover risk may increase significantly
This study will ensure that insulation levels, surge protection systems and equipment withstand capabilities are appropriately coordinated with expected system stresses.
Advanced PSCAD Modelling and Analysis
Power Projects will execute the study using PSCAD electromagnetic transient simulation software. A detailed project-specific model will be developed and validated using client-supplied network data, equipment parameters and operating scenarios.
Model Development Process
- Development of a detailed PSCAD network model
- Validation of transformer, transmission line and network parameters
- Review of insulation levels and surge arrester characteristics
- Verification of operating configurations and switching scenarios
Temporary Overvoltage (TOV) Assessment
The Temporary Overvoltage study will evaluate a range of operating and contingency scenarios, including:
Calculated overvoltages will be compared against surge arrester MCOV and TOV withstand capabilities to verify arrester suitability and equipment insulation performance.
Slow Front Overvoltage (SFO) Study
The SFO assessment includes:
- Transmission line energisation
- Transmission line re-energisation
- Switching surge evaluation
- Surge arrester performance assessment
The resulting overvoltages will be assessed against equipment switching impulse withstand levels.
Fast Front Overvoltage (FFO) Study
The FFO assessment will investigate:
- Back-flashover scenarios
- Lightning surge propagation into the substation
The resulting overvoltages will be evaluated against equipment Basic Insulation Levels (BIL).
Very Fast Front Overvoltage (VFFO) Assessment
The VFFO study will assess:
- GIS disconnector switching operations
- Trapped charge conditions
- High-frequency transient propagation within GIS equipment
- Insulation performance of GIS systems
Maximum transient voltages will be compared against GIS insulation withstand capability.
Transferred Surge Study (TSS)
The assessment includes:
- Surge transfer through transformer windings
- Surge propagation between voltage levels
- Impact assessment on connected equipment
Transient Recovery Voltage (TRV) Study
The study will evaluate:
- Circuit breaker interruption duty
- Post-fault voltage recovery characteristics
- Compliance with breaker performance requirements and applicable standards
Delivering Reliable Renewable Energy Evacuation Networks
Renewable energy projects connected to extra-high-voltage networks require detailed transient studies to ensure long-term reliability and equipment security.
Through this engagement, Power Projects will support:
Optimised insulation selection
Improved surge protection design
Reduced equipment failure risk
Enhanced transformer protection
Reliable operation of renewable energy evacuation systems
Alignment with international insulation coordination practices
Delivery Schedule
The complete study package will be delivered within a 4-week schedule following receipt of the purchase order and complete project inputs — despite the complexity of the electromagnetic transient simulations and the extensive range of transient phenomena being assessed.
Our Capability
Established in 2006, Power Projects provides specialist engineering services across a range of power system disciplines:
Insulation Coordination Studies
EHV and UHV transient analysis using PSCAD for renewable and utility projects
Electromagnetic Transient Studies
TOV, SFO, FFO, VFFO, TSS, TRV using industry-leading EMT simulation
Grid Compliance Studies
LVRT, HVRT, reactive power and power quality for renewable grid connections
Power System Analysis
Load flow, short circuit, stability, and protection using PSCAD, PSS®E, ETAP and DIgSILENT
Our team supports utilities, renewable energy developers and EPC contractors using industry-leading software tools including PSCAD, PSS®E, ETAP and DIgSILENT PowerFactory.