Automated Test Software (Core Value) Modern relay testers no longer require manual knob adjustment



Instead, through built-in software or connecting to a laptop, they achieve "one-click testing": Automatically search for action value: automatically increase current/voltage until the protection operates, recording the precise action value (e.g., overcurrent setting 5.00A, actual measured 4.98A). Automatically test operation time: from fault occurrence to protection trip signal (millisecond precision), verifying instantaneous and time-delay logic. Impedance characteristic scanning: automatically plot the impedance circle (Mho characteristic) and quadrilateral characteristic of distance protection to determine if the protection range is accurate. Differential protection testing: automatically scan the percentage restraint characteristic curve to verify the sensitivity and reliability of transformer/generator differential protection. Reclosing test: simulate the full process logic of "fault-trip-reclose-fault-trip again". C. Digital Substation Support (IEC 61850) This is a standard feature for equipment in 2026: GOOSE/SV messages: not only can output hardwired analog quantities, but also directly send and receive digital messages. Virtual terminal testing: directly test the logical coordination between Intelligent Electronic Devices (IEDs) on the fiber optic network without physical wiring. SCD file import: directly import the substation configuration file, automatically identify device addresses and data sets, greatly simplifying wiring and configuration. D. Power Amplification and Harmonic Simulation High-power output: built-in high-performance power amplifier can output large capacity current (e.g., 30A-60A per phase) to meet the needs of high-power protection devices or load testing. Harmonic superposition: can superimpose 2nd to 50th harmonics to test the anti-maloperation capability of protection devices under harmonic interference, or specifically test harmonic restraint functions. 3. "Ecological Linkage" with Your Existing Equipment In the complete test system you have built, the relay tester plays the role of "logic verifier": Table Related Equipment Linkage Scenario Specific Role High-current generator Complete set transmission test The high-current generator injects real high current (e.g., 1000A) on the primary side, while the relay tester monitors the secondary side current and simulates fault logic to verify the entire chain from CT -> protection device -> trip coil -> circuit breaker -> high-current interruption is correct. High-altitude wiring clamp On-site wiring In the high-voltage room or outdoor terminal box, use the high-altitude wiring clamp to safely connect the output wires of the relay tester to the protection panel terminal blocks at height for adding quantity tests. Test transformer Logic check after withstand voltage After the primary equipment has undergone withstand voltage test, it is necessary to confirm that the protection circuit is not damaged. Use the relay tester to add a small signal to confirm that the protection logic is still normal. DC resistance tester Circuit integrity First measure the DC resistance of the trip coil to confirm the path, then use the relay tester to send a command to see if it operates, complementing each other. 4. Typical Test Project Examples Overcurrent protection test: Simulation: A phase current slowly rises from 0A to 10A. Purpose: Verify that when the current exceeds the setting (e.g., 5A), the protection operates and trips within 0.5 seconds. Distance protection test: Simulation: Change the amplitude and phase angle of voltage and current to simulate fault points at different distances. Purpose: Plot the impedance diagram to ensure that the protection only clears faults on its own line without causing upstream tripping. Differential protection test: Simulation: Add on the high-voltage side