Protection
Protection engineers are tasked with designing, configuring, and implementing systems that are fast, secure, selective, and reliable. These systems must respond precisely and consistently under fault conditions—making thorough validation and testing critical. Yet, the growing complexity of interconnected grid components and evolving architectures has made comprehensive testing increasingly challenging, positioning HIL as a critical solution to enhance test coverage and develop more resilient grid protection schemes.
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Challenges
Protecting the unpredictable
As renewable penetration rises, the grid’s topology is more dynamic and its short-circuit ratio decreases, making fault detection and protection coordination more complex. Traditional protection systems struggle with weak grids and low-inertia conditions, where fault currents are less predictable.
System Integrity Protection Schemes (SIPS) must now function reliably across large, variable networks with fluctuating fault levels and real-time communication constraints. These evolving challenges demand high-fidelity testing environments that can replicate dynamic grid behavior and validate protection strategies under realistic operating conditions.
Demo
Traveling wave relay testing with FPGA-based real-time simulator
Watch a demonstration on how to use a real-time simulator to perform Hardware-in-the-Loop (HIL) testing of the latest Traveling Wave Fault Locators. The model of a power system network including a long transmission line is executed in real-time on FPGA at a time step of hundreds of nanoseconds. Low-power analog signals are sampled at 1MHz from the RTS and injected to two SEL-T400L relays. Various fault scenarios are applied to test the TW87 fault locating algorithms.
Benefits
Benefits of hardware-in-the-loop testing for protection relay
Hardware-in-the-loop (HIL) testing is revolutionizing protection relay validation and development. By simulating real-world grid conditions in a controlled environment, HIL testing offers unmatched precision and flexibility.
Traditional relay testing approach
Good and proven method for traditional scenarios.
Limitations: Open loop; Fixed V/I and ramp up; No data alteration/loss
Hardware-in-the-loop testing approach
Proven for R&D testing as well as validation of new and more complex protection algorithms.
Advantages: Closed loop to consider the effect of the relay on the grid; Topology-driven detailed EMT simulation; Capability to test complex schemes with several physical and virtual relays.
Connection types
OPAL-RT HIL configurations for power system protection
We provide a range of portable, high-performing real-time simulators specifically designed for protection engineers. The company’s simulation environment is capable of providing large and complex model-based or basic functional test scenarios, while simultaneously supporting an array of inputs and outputs for uncompromised connectivity. OPAL-RT’s supported connection types are future-ready, providing systems capable of emulating numerous IEDs with IEC 61850 GOOSE and Sampled Values streams or other communication protocols such as DNP3 and Modbus.
Use case 1
Test protection equipment via analog and digital interfaces, and use amplifiers to include the effects of equipment current and voltage transformers, or connect directly to a low-level interface. The high voltage interface panel is used to match the right voltage level with a relay for digital signals.
Use case 2
Test protection equipment via analog for PT and CT signals, and use the amplifier to match the voltage and current transformer. System information is connected via IEC61850 GOOSE via publishers and subscribers.
Use case 3
Connect protection systems with IEC61850 Sampled Value and GOOSE via publishers and subscribers. Use a GPS clock to obtain high-precision simulation synchronization and time-stamping.
Success story
State-of-the-art prototype testing of PAC devices for the power industry
Learn how Protecta leverages our simulator to perform real-time HIL testing of protection and control devices. Their setup enables accurate validation of functions like inrush detection, CT saturation, arc suppression, and SIPS logic under dynamic grid conditions—supporting automated test sequences and multi-IED coordination.
The real-time simulator from OPAL-RT has revolutionized our R&D and testing processes at Protecta Electronics. The simulator enables automated testing of a large number of test cases in a very simple way, saves time, and ensures compliance with international standards and customer-specific requirements.
Kristóf Hackel
Chief R&D Officer at Protecta Electronics
Products
The essentials for protection testing
By enabling the validation of critical what-if scenarios, we help protection engineers anticipate vulnerabilities and fine-tune their systems before deployment.
EMT Simulation and HIL Testing
HYPERSIM
High-fidelity platform for EMT simulation, SIL and HIL testing, ideal for validating control, protection, grid integration and large-scale stability across all stages of power system development.
Compact mid-range simulator
OP4610XG
Compact yet powerful mid-range simulator offering an all-in-one solution that combines the latest 6-core AMD Ryzen™ 5 CPU with the power of an AMD Kintex™-7 410T FPGA.
FAQ
Find the answers to your questions
What communication protocols do you support?
Consult our comprehensive list of supported protocols here: Communication Protocols.
Let’s get to work
Please contact us for more details or any inquiries. Our local team of experts will be pleased to promptly answer any of your questions.