Classification of Relay Protection Test Instruments
Based on the technical principle, output characteristics and portability, it is mainly divided into the following categories:
1. Classified by technological development and output waveform
Intelligent (Microcomputer/Digital)
Features: Utilizes DSP + FPGA or ARM control, outputs pure sine waves, has high accuracy (stable for small signals), and supports GPS/Beidou synchronization.
Mainstream products: The absolutely dominant products currently available in the market (such as mid-to-high-end models of brands like Yongli, Boelectric, and Meil).
Applicable to: Commissioning of intelligent substations and digital substations.
Traditional type (alternating current / analog type)
Features: Based on the principles of voltage regulator and phase shifter, it is large in size and has low precision. It has basically been phased out.
Transistor/Integrated Circuit Type
Features: An early product with a single function, mainly used for the calibration of electromagnetic relays.
Integrated Relay Protection Test Instrument
2. Classified by physical structure and portability
Handheld
Features: Compact and lightweight, powered by battery, with relatively simplified functions (mainly for single-phase or simple three-phase testing).
Applicable scenarios: Patrol inspection, on-site rapid troubleshooting, simple overcurrent relay testing.
Portable
Features: High integration, with a weight typically ranging from 10 to 20 kilograms, it is the most widely used type.
Applicable to: The majority of on-site commissioning and preventive tests in substations.
Desktop / Rack-mounted
Features: High power, numerous channels, comprehensive functions, usually placed in laboratories or maintenance centers.
Applicable scenarios: Factory testing, R&D verification, teaching and training.
3. Classified by output channels and functions
Single-phase relay protection tester
It can only output single-phase or phase-separated voltage and current simultaneously, and is mainly used for testing individual relays (such as single-phase voltage and current relays).
Three-phase/Six-phase Electrical Protection Tester
The standard configuration includes four-phase voltages (Ua, Ub, Uc, Ux) and three-phase currents (Ia, Ib, Ic).
Six-phase/ Twelve-phase tester: Capable of multi-channel current output (six-phase current), mainly used for testing differential protection (current needs to be applied to both the high-voltage side and the low-voltage side simultaneously).
Specialized testing instrument
Such as transformer testers (used for testing the characteristics and transformation ratios of CT/PT), DC system testers, and GPS synchronization testers (used for joint debugging of line longitudinal protection).
II. Main Application Scenarios
The relay protection tester covers the entire lifecycle management of power equipment from its manufacture to its retirement:
Infrastructure installation and commissioning
Before the new substation is put into operation, all protection devices are subjected to power-on simulation tests to verify the correctness of the settings, logic circuits, and trip-closing circuits.
Preventive tests / Regular maintenance inspections
After the power grid equipment has been in operation for a period of time (usually 1 to 6 years), according to the procedures, the accuracy of the protection devices and the action values should be rechecked.
Fault Diagnosis and Analysis
After an accident occurs in the power grid, the fault data is replayed to check whether the protection devices have malfunctioned or failed to operate.
Technical renovation of protection devices
After replacing the new protection device, conduct load testing and simulation verification before vector checking.
Teaching and Training
In power engineering colleges and internal training sessions of enterprises, various types of faults in the power system (such as single-phase grounding, inter-phase short circuit, and transitional faults, etc.) are simulated.
