Protection & Control Schemes

Overview of Protection & Control

On Grid Engineering delivers comprehensive protection and control solutions that safeguard generation, transmission, and distribution assets. Our team combines deep expertise in relay coordination, control logic, and system automation to design schemes that detect faults, isolate issues, and maintain continuity of service.

From substation protection to system-wide control architectures, we tailor each design to meet performance requirements, comply with industry standards, and support seamless integration with existing infrastructure.

Protection System Studies & Modeling

Accurate system modeling is foundational to effective protection design. Our services include:

• Short-Circuit Analysis: Calculating fault currents to specify breakers, CT/VT ratings, and relay settings.
• Relay Coordination Studies: Time-current curve alignment to ensure selective tripping and minimal service disruption.
• Power System Transient Modeling: EMTP and digital simulations for transient overvoltages, ferroresonance, and switching surges.
• Arc Flash Studies: Evaluating incident energy levels to recommend appropriate PPE, labeling, and boundary clearances.
• System Stability Analysis: Transient stability studies to assess generator ride-through and grid support during faults.

Protection Scheme Design

We develop protection schemes for medium-voltage and low-voltage applications across utility-scale solar, BESS, and hybrid systems:

• Feeder Protection: Overcurrent, directional overcurrent, breaker failure, and undervoltage/overvoltage
• Transformer Protection: Differential, restricted earth fault, inrush restraint, and overload protection
• Inverter Protection Coordination: Relay settings for grid-code compliance and ride-through behavior
• BESS Protection Support: DC fuse coordination, AC fault isolation, and interlock logic development
• Breaker and Relay Settings: TCC curve development, relay programming, and coordination studies

Protection Relay Specification & Settings

Selecting and configuring relays is critical to scheme performance. Our approach includes:

• Relay Type Selection: Electromechanical, static, or microprocessor relays based on application, accuracy, and communication needs.
• Setting Calculation: Deriving overcurrent, overvoltage, underfrequency, and differential settings from fault studies and load profiles.
• Scheme Logic Development: Implementing directional, distance, and adaptive protection features for dynamic grid conditions.
• Firmware & Security Updates: Ensuring relays operate with the latest enhancements and cybersecurity patches.
• IEC & ANSI Code Compliance: Aligning settings and functions with regional protection standards.

Maintenance Strategies & Lifecycle Management

Proper maintenance extends equipment life and ensures continued reliability. We offer:

• Preventive Maintenance Plans: Scheduled inspections for relays, control cabling, batteries, and switchgear.
• Firmware & Configuration Management: Documenting and updating relay settings, control logic, and communication parameters.
• Troubleshooting & Fault Analysis: Post-event investigation to identify root causes and implement corrective actions.
• Spare Parts & Obsolescence Management: Lifecycle planning for legacy IEDs and transition strategies to next-generation platforms.
• Training & Knowledge Transfer: Equipping client teams with skills for local maintenance, testing, and system upgrades.

Future-Proofing Protection & Control

Our forward-looking approach ensures protection and control systems remain robust as grid complexity grows:

• Integration of Renewable & DER Protection: Designing schemes that accommodate bidirectional power flow and inverter response characteristics.
• Grid Edge Intelligence: Embedding intelligence at substations and feeders for autonomous fault detection and restoration.
• Machine Learning & AI Applications: Predicting grid faults, optimizing relay settings, and improving system resilience through data analytics.
• IEC 61850 Conformance Testing: Ensuring interoperability and future integration with smart grid architectures.
• Modular Protection Platforms: Enabling easy upgrades and expansions as system requirements evolve over decades.