Microcomputer-based Relay Protection Test Set is a special precision instrument used in power systems for testing, calibrating, and maintaining various relay protection devices (such as line protection, transformer protection, generator protection, etc.). It is the "stethoscope" and "scalpel" for relay protection personnel. By simulating various normal operating states and complex fault conditions in the power grid (such as short circuits, grounding, line breaks, frequency fluctuations, etc.), it verifies whether the action logic, action time, and action values of protection devices are correct. The following is the core knowledge system of this device: 1. Main Functions Simulated fault quantity output: It can output three-phase voltages (Ua, Ub, Uc) and three-phase currents (Ia, Ib, Ic) with high precision, even zero-sequence voltage (3U0) and zero-sequence current (3I0). Amplitude adjustable: Continuously adjustable from 0 to rated value. Phase adjustable: Arbitrarily change the phase angle between voltage and current (0°-360°). Frequency adjustable: Simulate system frequency fluctuations (e.g., 45Hz-55Hz). Automated test modules: Built-in multiple standard test procedures, one-click completion of complex tests: Whole group test: Simulate permanent faults, test the entire process logic and time of protection tripping, reclosing, and post-acceleration. Impedance characteristic test: Automatically scan and draw the action boundary of distance protection impedance circle (or quadrilateral). Differential protection test: Simulate the differential current of transformers or generators, test the percentage restraint characteristic curve. Harmonic test: Superimpose 2-21 harmonics on the fundamental wave, test harmonic braking function. State sequence: Users can customize multiple states (e.g., normal->fault A->clear->reclose->fault B) to simulate complex sequential logic. Binary input/output detection: Binary input: Receive trip, close, and signal contacts from protection devices, automatically record action time (accuracy usually up to 0.1ms). Binary output: The tester can output contact signals to trigger external devices or simulate circuit breaker positions. 2. Core Application Scenarios Pre-commissioning acceptance of new equipment: Verify whether the wiring of newly installed protection devices is correct, whether the settings are accurate, and whether the logic meets design requirements. Periodic preventive tests: According to regulations (e.g., every 1-3 years), calibrate protection devices in operation to prevent misoperation or refusal caused by component aging. Fault analysis: When a power grid accident causes protection to operate (or not operate), use the tester to reproduce the fault waveform and analyze whether the protection behavior is correct. Scientific research and teaching: Used in university laboratories or research institutions to study new protection algorithms. 3. Technical Characteristics and Development Trends High precision and high stability: Modern testers typically use DSP (Digital Signal Processing) or FPGA technology, with extremely low output waveform distortion (<0.2%) and phase accuracy up to 0.1°. Multi-phase output capability: Mainstream devices have six-phase voltage and six-phase current outputs, which can not only test conventional protection but also easily handle complex differential protection (requiring independent multi-side current sources) and automatic transfer switching device tests. GPS synchronization: High-end models support GPS/Beidou timing, enabling multiple testers to synchronize remotely for traveling wave protection or longitudinal differential protection tests on long-distance transmission lines. Digital interface (IEC 61850): With the popularity of smart substations, the new generation of testers not only outputs analog quantities (hardwired) but also has fiber optic Ethernet ports, capable of directly sending and parsing SV (Sampled Values) and GOOSE (Generic Object Oriented Substation Event) messages, achieving closed-loop testing of digital protection devices. Portable design: High integration, lightweight, with built-in large-capacity lithium battery, suitable for field operations without power supply.
