Solar Utility Power Plants

What is EHV Engineering for Solar Plants?

EHV engineering encompasses the design, analysis, and implementation of high-voltage electrical systems to transmission levels and interconnect with utility grid infrastructure. This includes power transformers, high-voltage switchgear, protection and control systems, transmission line design, substation engineering, and sophisticated grid integration studies.

Why Specialized EHV Expertise is Essential

High voltage systems operate under extreme electrical stresses where design errors can result in catastrophic equipment failures, personnel safety incidents, grid disturbances affecting thousands of customers, expensive utility-mandated modifications, and permanent limitations on plant output capacity. Generic electrical engineering expertise is insufficient—EHV systems require specialized knowledge of transmission standards, utility grid codes, protection coordination, insulation coordination, and transient phenomena.

Comprehensive Grid Integration Studies

Grid Connection Feasibility Analysis
We begin with comprehensive analysis of grid connection options, evaluating potential points of interconnection (POI), distance to suitable connection points, available capacity at each option, voltage level requirements and economics, transmission line routing alternatives, and utility interconnection procedures and timelines.

Utility Coordination and Application Process
We manage utility interconnection applications including preparation of connection applications, coordination with transmission system operators (TSOs), participation in utility interconnection studies, negotiation of connection agreements, and securing grid capacity allocation.

Each utility has unique procedures and requirements. Our regional experience with DEWA (Dubai), ADDC/TRANSCO (Abu Dhabi), SEC (Saudi Arabia), OETC (Oman), and other MENA utilities streamlines approval processes.

Load Flow and Power System Analysis
Comprehensive load flow studies grid voltage profiles, power flows, and system losses.

Steady-State Load Flow Studies
We perform load flow analysis for multiple operating scenarios including maximum generation with minimum load, minimum generation with maximum load, N-1 contingency conditions (single element outage), seasonal variations in load and generation, and different grid topology configurations.

Voltage Stability Assessment
We evaluate voltage stability margins ensuring the grid can maintain acceptable voltages under various disturbances including sudden load changes, cloud transient events causing rapid generation drops, faults on transmission lines, and loss of major generation or transmission elements.

Short Circuit Analysis
Short circuit studies determine fault current levels throughout the electrical system.

Fault Level Calculations
We calculate fault currents for three-phase faults, line-to-ground faults, line-to-line faults, double line-to-ground faults, at various locations including generator terminals, transformer primary and secondary, switchgear busbars, and point of interconnection.

These calculations determine equipment ratings required to safely interrupt fault currents. Underrated equipment can catastrophically fail during faults, causing fires or explosions.

Equipment Rating Verification
Based on fault analysis, we verify adequate ratings for circuit breakers and switchgear, power transformers, instrument transformers (CTs and VTs), cables and conductors, and surge arresters.

We ensure all equipment can withstand worst-case fault stresses including mechanical forces from fault currents and thermal stresses during fault clearing.

Protection Coordination Studies
Comprehensive protection studies ensure faults are cleared quickly while minimizing unnecessary trips.

Protection Philosophy Development
We develop overall protection strategies including primary and backup protection schemes, protection zones and overlaps, coordination between solar plant and utility protections, fault clearing time objectives, and selectivity requirements.

Relay Settings Calculation
We calculate precise settings for overcurrent relays (directional and non-directional), distance protection relays, differential protection, under/over voltage relays, under/over frequency relays, reverse power relays, and loss of mains protection.

Improper relay coordination causes either failure to clear faults (safety risk) or nuisance tripping (availability loss). Our studies optimize both security and reliability.

Coordination Time-Current Curves
We develop and verify time-current coordination curves ensuring proper discrimination between protection devices, meeting utility clearing time requirements, coordinating with utility upstream protection, and minimizing fault damage while ensuring selectivity.

Harmonics and Power Quality Analysis
Harmonics that can affect grid power quality and equipment.

Harmonic Assessment
We model harmonic current injection from solar inverters, evaluate cumulative harmonic distortion at POI, assess voltage distortion against IEEE 519 or local standards, analyze resonance conditions that amplify harmonics, and determine filtering requirements if necessary.

Excessive harmonics cause equipment overheating, premature failure, and interference with communication systems. Utilities impose strict limits on harmonic injection.

Power Factor and Reactive Power Studies
We analyze plant power factor over different operating conditions, reactive power requirements for voltage support, capacitor bank or STATCOM requirements, and compliance with utility reactive power mandates.

Many utilities require solar plants to provide reactive power support for grid voltage regulation, necessitating oversized inverters or additional reactive compensation equipment.

Transient Stability Studies
We perform dynamic stability analysis.

Fault Ride-Through Analysis
We model to grid faults including voltage dip ride-through capability, frequency deviation response, active and reactive current injection during faults, recovery behavior after fault clearing, and compliance with grid code requirements (voltage and frequency ride-through).

Modern grid codes require solar plants to remain connected during grid disturbances rather than tripping offline—avoiding cascading outages. Our studies verify compliance with these stringent requirements.

System Restoration Studies
We analyze solar plant behavior during grid restoration including energization transient analysis, black start capability assessment, islanding detection and prevention, and synchronization procedures.

High Voltage Electrical System Design

Step-Up Transformer Design
Power transformers step up solar plant output (typically 400V-800V from inverters) to transmission voltage.

Transformer Specification
We specify transformer parameters including voltage ratios and tap changer requirements, MVA rating and overload capability, impedance and loss specifications, insulation class and BIL ratings, cooling system (ONAN, ONAF, OFAF), and noise level requirements.

We optimize transformer specifications balancing capital cost, efficiency losses, fault current contribution, and physical constraints.

Transformer Protection Design
We design comprehensive transformer protection including Buchholz relay for oil-surge detection, differential protection, overcurrent protection, overload and temperature monitoring, and oil level and temperature alarms.

High Voltage Switchgear Design
Switchgear provides connection, isolation, and protection at transmission voltage.

Switchgear Configuration
We design switchgear arrangements using gas-insulated switchgear (GIS), air-insulated switchgear (AIS), or hybrid solutions, determining optimal bus configurations (single bus, main and transfer, breaker-and-a-half), specifying circuit breaker ratings and interrupting capacity, and selecting disconnect switch and earthing switch arrangements.

GIS offers compact footprint ideal for space-constrained sites, while AIS provides lower cost for larger installations. We optimize selection based on project requirements.

Instrument Transformer Design
We specify current transformers (CTs) for metering and protection with appropriate accuracy classes, voltage transformers (VTs) for measurement and sync check, and metering equipment for revenue accounting.

Accurate revenue metering is critical for PPA compliance and financial performance tracking.

Control and Protection System Architecture
We design integrated protection and control systems including numerical protection relays, SCADA (supervisory control and data acquisition) systems, communication networks (fiber optic, ethernet), remote monitoring and control capabilities, and cybersecurity provisions.

Modern solar plants require sophisticated automation enabling remote operation, real-time performance monitoring, and rapid fault response.

Earthing System Design
Proper earthing ensures personnel safety and equipment protection.

Earthing Design Calculations
We perform earth grid design calculations including soil resistivity measurements and modeling, touch and step voltage calculations, earth grid conductor sizing, earth electrode design and spacing, and lightning protection system integration.

Inadequate earthing creates lethal safety risks during faults. We design robust earthing systems meeting international safety standards.

Transmission Line Engineering
For projects requiring dedicated transmission lines to reach POI, we provide complete transmission line design.

Route Selection and Survey
We optimize transmission line routes considering shortest practical distance, terrain and right-of-way constraints, environmental and permitting considerations, construction access, and land acquisition requirements.

Transmission Line Design
We design transmission lines including conductor selection and sizing, tower design and foundation requirements, insulator selection and coordination, clearance requirements and sag-tension calculations, and lightning protection (shield wires).

Regulatory and Grid Code Compliance

Utility Grid Code Requirements
We ensure compliance with utility-specific grid codes including voltage and frequency operating ranges, fault ride-through requirements, reactive power capability requirements, power quality standards (harmonics, flicker), frequency response and ramping requirements, and communication and data exchange protocols.

International Standards Compliance
We design to international standards including IEEE standards for protection, grounding, and power quality, IEC standards for equipment and testing, local electrical regulations and codes, and safety standards.

Interconnection Agreement Requirements
We address all technical requirements in interconnection agreements including metering and data provision, remote monitoring access, curtailment and dispatch protocols, maintenance coordination procedures, and testing and commissioning requirements.

Project Implementation Support

Vendor Specification and Procurement
We develop detailed technical specifications for EHV equipment, support tender evaluation of HV equipment suppliers, review shop drawings and factory test procedures, and witness factory acceptance testing (FAT).

High voltage equipment represents major capital investment. Rigorous procurement ensures quality and value.

Construction Supervision
We provide specialized HV construction oversight including installation quality inspection, testing and commissioning supervision, protection relay testing and setting verification, and pre-energization system checks.

Commissioning Support
We support critical commissioning activities including energization procedures and safety protocols, protection system functional testing, metering and SCADA system commissioning, and utility interconnection testing and approval.

Why Choose Clenergize for EHV Engineering?

Our team includes licensed electrical engineers specializing in power systems, transmission planning experts, protection and control specialists, and professionals with decades of combined experience in utility-scale renewable energy interconnection. We’ve successfully designed and commissioned grid connections for over 1200MW of solar capacity across the MENA region.

Our independence from equipment vendors ensures unbiased equipment specifications and vendor selection—we recommend optimal solutions for your project, not products from affiliated manufacturers. This independence has consistently delivered better value and performance for clients.

Getting Started

EHV engineering typically begins during the detailed feasibility stage and continues through construction commissioning. Early engagement during feasibility ensures grid connection considerations inform site selection and project sizing decisions.

Initial EHV assessment requires project capacity and voltage level, proposed POI location and utility, preliminary single line diagram if available, utility interconnection study results if obtained, and project development timeline.

Contact Clenergize Consultants today to leverage our specialized EHV engineering expertise. Our comprehensive approach to high voltage design and grid integration ensures your utility solar plant connects safely, reliably, and cost-effectively to power transmission systems—protecting your investment and maximizing long-term project success in the competitive MENA solar energy market.