Portable relay protection test instruments are the core tools for verifying the accuracy of relay protection and automation devices in power systems. The rational selection and standardized application of these instruments are the key foundations for ensuring the efficiency, accuracy, and safety of testing work.
Selection Methodology: A Four-Step Decision Path Based on Requirements
Selection is not merely a product screening process; it must be based on a systematic analysis of one’s own working scenarios and core tasks, following the following four-step decision logic:
Step 1: Define the Testing Task – Clarify “What to Test” and “Where to Test”
This is the starting point of the selection decision, directly determining the functional baseline of the instrument.
Test Object
It is necessary to clearly define the main types of test objects, including line protection, transformer protection, generator protection, or merging units and intelligent terminals in smart substations. Different devices have significant differences in the complexity of testing requirements. Application scenarios
Laboratory / Factory Debugging: Emphasis should be placed on comprehensive functionality, test accuracy, and a rich set of test templates to deeply verify the performance of the device.
On-site Commissioning / Maintenance: Portability, structural robustness, ease of operation, and battery life should be prioritized to adapt to the complex and changeable on-site environment.
Complex Analysis / Fault Reproduction: The instrument should have high-performance computing capabilities, multi-channel synchronization functions, and advanced software configurations to simulate system oscillations, replay fault recordings, and handle other complex conditions.
Step 2: Evaluate Core Performance – Focus on “Hard Indicators”
After clarifying the test tasks, it is necessary to strictly verify the key technical parameters of the instrument, which is the core capability support for completing the test tasks.
Channel Configuration
Channel configuration is the basic framework for realizing the instrument’s functions:
Current Output: A 6-phase current configuration can flexibly handle complex test scenarios such as main transformer differential (simultaneous addition on both high and low voltage sides), and is the mainstream choice for professional debugging; a 4-phase current (3-phase + 1 zero sequence) can meet the basic requirements of most differential protection tests.
Voltage Output: A 4-phase voltage (3-phase + 1 neutral point) is the standard configuration; if testing synchronization functions or more voltage variables is required, a higher phase number voltage output configuration should be selected.
Input/Output Channels: Sufficient input channels (typically 8 or more) are used to capture protection action signals; output channels are mainly used to simulate switch positions or trigger external devices.
Output Capacity and Accuracy
Output capacity and accuracy are the core guarantees for the instrument’s test accuracy:
Current Capacity: A single-phase 30A (sustainable for 1-10 seconds) can meet the needs of simulating most secondary side fault currents of current transformers; for special scenarios such as motor starting, a current output capacity of 45A or more should be selected.
Accuracy Grade: The output accuracy of current and voltage should be better than 0.1%, which is a prerequisite for conducting precise protection setting verification and characteristic curve scanning.
Step 3: Examine Functions and Software – Review “Soft Power”
Hardware is the foundation for the instrument’s operation, while software functions determine the instrument’s level of intelligence and ease of use.
Essential Test Modules
It is necessary to ensure that basic functions such as manual testing, state sequence (a core tool for simulating complex timing logic), differential characteristic testing (with multiple braking curves built-in), overall drive testing, and harmonic analysis are complete.
Advanced Analysis and Simulation Capabilities
Functions such as fault recording replay (supporting Comtrade format), system oscillation simulation, and intelligent substation optical digital testing (supporting IEC 61850-9-2 SV and GOOSE protocols) are key configurations for meeting high-end debugging requirements and intelligent substation testing scenarios.
Work Efficiency Design
Designs such as an intuitive graphical operation interface, one-click generation of standard test reports, and a customizable test template library can significantly improve on-site test work efficiency.
Step 4: Comprehensive Evaluation and Decision – Balance “Demand and Budget”
Under the premise that technical indicators meet the test requirements, the following dimensions should be comprehensively evaluated for the final decision:
Portability and Reliability
True portability requires a balance between weight (typically controlled within 15kg) and structural robustness, while also having a long-lasting battery and AC/DC adaptive power supply capabilities to adapt to different on-site power supply conditions.
Expandability and Future Compatibility
It is necessary to pay attention to whether the instrument reserves interfaces and software upgrade space to meet future technological upgrade needs (such as adaptation to new communication protocols), ensuring the long-term use value of the instrument.
Service and Support
Support such as technical support response speed, calibration service network coverage, and professional training resources are important supports for ensuring the stable operation of the instrument throughout its life cycle.
Post time: Dec-15-2025