The selection of a relay protection comprehensive test instrument is a systematic task that requires a comprehensive assessment of test requirements, equipment performance, ease of use, and budget. The following are the core selection steps and considerations:
1. Clarify Core Test Requirements (Application Scenario Positioning)
This is the primary basis for the selection process and needs to be precisely defined from three dimensions: protection type, test object, and test depth.
Protection Type
Traditional protection: includes overcurrent, overvoltage, undervoltage, frequency, differential, impedance (distance) protection, etc.
Complex protection: includes optical fiber differential (requires an internal optical digital interface, supporting IEC 61850-9-2/9-2LE SV), traveling wave distance measurement, harmonic analysis, fault replay, etc.
Automation devices: involves automatic transfer switch (ATS), fast switching devices, synchronization devices, fault isolation devices, etc.
Test Object
Generator / Transformer Protection: requires a large current output capability (such as single-phase continuous output > 30A) and complex harmonic test functions.
Busbar / Line Protection: requires multiple current and voltage output interfaces (such as 6 current and 4 voltage channels or more) to meet the requirements of differential and distance protection tests.
Motor Protection: needs to support positive and negative sequence component tests and thermal overload model simulation.
Intelligent substation equipment (merging unit MU, intelligent terminal, protection and measurement control integrated device): must be compatible with IEC 61850 standards (GOOSE, SV) and IEEE 1588 time synchronization protocol.
Test Depth
On-site commissioning / maintenance: focuses on equipment portability, ease of operation, battery life, and the richness of pre-configured general test templates.
Laboratory / R&D / Factory Acceptance: focuses on equipment measurement accuracy, output power, functional comprehensiveness, as well as the software’s analysis capabilities and report generation capabilities.
2. Key Performance Indicators and Hardware Configuration
It is necessary to pay close attention to core indicators such as output channels, precision waveforms, digital interfaces, and software functions.
Number and Capacity of Output Channels
Current Output: Common configurations are 3-phase or 6-phase, with 6-phase current output capable of flexibly simulating various faults (such as phase differential), suitable for complex protection tests. Attention should be paid to the single-phase maximum continuous output current and short-term output capability (such as 100A/1 second).
Voltage Output: Typically configured as 4-phase (3-phase voltage + 1 open delta voltage), and the rated voltage (such as 120V / phase) and load capacity need to be verified.
DC Auxiliary Output: Must have the ability to power the tested device (DC 110V/220V) and simulate DC quantities.
Output Precision and Waveform Quality
Total Harmonic Distortion (THD) should be controlled at a low level (such as <0.1%) to ensure the purity of the output waveform.
Amplitude and phase accuracy within the basic range typically need to be better than 0.1%.
Synchronization accuracy between channels should reach the microsecond level to meet the strict requirements of tests such as differential protection.
Digital Interfaces and Protocol Support (Core for Intelligent Substations)
At least 2 optical Ethernet ports are required, with independent send and receive functions.
It must support IEC 61850-9-2/9-2LE (SV sampling values), GOOSE (inputs/outputs), MMS (for setting reading and writing, etc.) protocols.
Time synchronization methods should be compatible with IRIG-B, PPS, PTP (IEEE 1588) standards.
It should be equipped with traditional interfaces, including active/passive switchable input terminals and open contact output terminals.
Software Functionality and Ease of Use
The operation software should have an intuitive human-machine interface and support offline editing of test plans.
It should have built-in automatic test modules for common protection types (differential, distance, inverse-time overcurrent, etc.) and be able to generate test reports with one click. The core function is the sequence test, which should support users to freely edit multiple groups of continuous and dynamic test states to simulate complex fault processes. At the same time, attention should be paid to the flexibility of the number of states and transition conditions (time, input quantity, trigger signal, etc.).
It should have a fault replay function, which can import Comtrade format fault recording data for retesting.
The output report should have a standardized format, support customization, and meet the relevant requirements for acceptance and archiving.
III. Services and Budget Planning After-sales service
Attention should be paid to the training services for equipment, software upgrade services, the response speed of technical support, as well as the calibration cycle and calibration costs of the equipment. Budget allocation should be based on the aforementioned requirements to determine a reasonable budget range. High-end six-phase relay protection testers with comprehensive functions are relatively expensive, while basic three-phase/four-phase relay protection testers can meet the needs of most conventional test scenarios.
Post time: Jan-13-2026