The core selection of the three-phase relay protection tester is based on demand. The main basis for selection is the test object and test items, while also taking into account future equipment expansion requirements.
I. Core Considerations
(1) Test Object
Equipment Type: Clearly define the test object as traditional electromagnetic relays or mainstream micro-type protection devices. The testing of micro-type protection devices has higher requirements for the software functions and communication capabilities of the equipment.
Voltage / Current Level: Based on the test scenario, it could be 10kV distribution line protection or 500kV ultra-high voltage line protection, etc. Determine the current and voltage output capacity of the tester.
Protection Function: Based on actual needs, clearly define the protection functions to be tested, which are commonly including overcurrent, instantaneous trip, overvoltage / undervoltage, differential, impedance, direction, frequency, synchronization, etc.
(2) Output Channels and Capacity
Channels: The basic configuration of the three-phase relay protection tester needs to meet 3-phase current + 3-phase voltage + 1 input channel + 1 output channel; for complex test scenarios such as transformer differential and busbar protection, higher-configured equipment with 6-phase current + 6-phase voltage or higher is required.
Current Output: The current output has conventional levels such as 30A / phase, 50A / phase, 75A / phase, etc. The short-term output current of the equipment can be increased to higher standards such as 120A. During selection, ensure that the requirements for large short-circuit current testing and CT saturation tests are met.
Voltage Output: The voltage output is typically 75V / phase, 125V / phase and higher specifications. It needs to match the rated voltage of the PT secondary side (100V or 57.7V), and also meet the actual requirements of overvoltage testing.
(3) Software Functionality and Usability
Built-in Test Modules: Pay attention to whether the equipment is pre-set with one-click standard test templates such as overcurrent, time characteristics, impedance boundary scanning, etc., to improve test efficiency.
Graphical Operation: Preferentially choose equipment with an intuitive interface, which can facilitate the convenient drawing of characteristic curves and automatic testing.
Sequence / State Sequence Function: This function is the core of testing complex logic such as automatic reclosing and standby power auto-switching, and is an important consideration point for selection.
Differential Protection Test: Check if the equipment is equipped with a dedicated intelligent differential test module, which can automatically calculate and draw the proportional braking characteristic curve.
(4) Accuracy and Performance
Output Accuracy: The output accuracy of current, voltage, phase, and frequency needs to meet the industry standard requirements of 0.1% – 0.2%.
Time Measurement Accuracy: The measurement accuracy of protection action time needs to reach the standard of 0.1ms.
(5) Portability and Power Supply
Portability: Based on the usage field, distinguish between laboratory testing and on-site testing. The equipment used for on-site testing needs to be lightweight, sturdy, and equipped with handles, wheels, etc., for easy mobility.
Power Supply: Confirm that the equipment’s power supply is AC 220V, or whether it supports DC power supply. DC power supply is suitable for on-site testing scenarios such as substations without AC power.
II. Common Model Classification
Basic Type (4-5 Channels): The core configuration is 3-phase current + 3-phase voltage + auxiliary channels, with relatively simple functions, suitable for routine protection testing of 35kV and below distribution systems.
Standard Type (6 Channels): It is the classic configuration of 3-phase voltage / 3-phase current, capable of meeting the protection testing requirements of most equipment such as 110kV and below lines, transformers, and motors, and is the mainstream selection category. High-performance type (12 channels and above): The core configuration is 6-phase voltage / 6-phase current and higher specifications, suitable for testing scenarios of complex protection devices, mainly including transformer differential protection, generator-transformer group differential protection, busbar differential protection, as well as testing tasks that require simulating multiple sections of lines simultaneously.
III. Execution Standards and Procedures
When conducting tests using a three-phase electrical protection tester, it is necessary to strictly follow the relevant standards and procedures of the state and the power industry. The relevant standards are mainly divided into two categories: product manufacturing standards and testing work standards.
(1) Main technical standards (product manufacturing standards)
These standards specify the technical indicators that the three-phase electrical protection tester itself must meet, mainly including:
GB/T 7261-2016 “Basic Test Methods for Relay Protection and Safety Automatic Devices”
DL/T 624-2010 “Technical Conditions for Microcomputer Test Devices of Relay Protection”, which is the core manufacturing standard for this type of equipment in the domestic power industry.
(2) Main inspection procedures (testing work standards)
These standards regulate the inspection process and requirements of relay protection devices, mainly including:
GB/T 14285-2006 “Technical Regulations for Relay Protection and Safety Automatic Devices”
DL/T 995-2016 “Testing Regulations for Relay Protection and Grid Safety Automatic Devices”, which is the core guiding document for on-site testing work, clearly stipulating the types of tests (new installation test, regular test, using the device for circuit breaker tripping test, etc.) and test contents (insulation check, power-on check, setting value check, function verification, complete set test, with circuit breaker transmission, etc.).
Enterprise standards formulated by domestic power grid enterprises, these standards are usually more strict and more specific than industry standards, such as the relevant procedures for relay protection condition-based maintenance tests.
Post time: Jan-28-2026