Whether testing the mechanical characteristics or dynamic characteristics of switches, the test standards and requirements are completely consistent, and all must comply with national standards, industry regulations, special guidelines, and instrument metrology standards. The following is a summary of the currently effective and essential standards and regulations in the field of power testing, categorized by application scenario, clarifying the test basis and scope of application.
I. Basic General National Standards These standards form the basis for testing the mechanical characteristics of high-voltage switches, clearly defining parameter definitions and basic test requirements, and are applicable to high-voltage switches of all voltage levels.
1. GB/T 1984-2024 “High-Voltage AC Circuit Breakers”: This is the core basic national standard for circuit breaker products, clearly defining the definitions, technical indicators, and basic test requirements for various mechanical characteristic parameters (initial opening/closing speed, opening and closing time, travel, bounce, etc.). It is the core basis for all mechanical characteristic tests, replacing the relevant provisions on mechanical parameters in the older version of the standard. 2. GB/T 2900.20 *Electrical Engineering Terminology – High-Voltage Switchgear and Controlgear*: Standardizes the definitions of all related terms such as mechanical characteristics, dynamic characteristics, opening and closing times, speed, and stroke, regulating industry terminology and avoiding testing errors caused by terminological confusion.
3. GB 3309-89 *Mechanical Testing of High-Voltage Switchgear at Room Temperature*: Clarifies the general methods, environmental conditions, test procedures, and safety requirements for mechanical testing of high-voltage switches at room temperature, providing basic operating specifications for field testing.
4. IEC 62271 *General Technical Requirements for High-Voltage Switchgear*: An internationally recognized standard, aligned with domestic national standards, applicable to the mechanical characteristic testing of imported high-voltage switches in international projects, clarifying internationally unified parameter limits and test methods.
II. On-site Acceptance Test Procedures (Mandatory for New Equipment Acceptance) GB 50150-2016 “Electrical Installation Engineering – Standard for Acceptance Tests of Electrical Equipment”: Mandatory procedures for on-site acceptance of new equipment installations. Chapter 12, “Circuit Breaker Testing,” clearly defines the mandatory mechanical characteristic test items, which are the core basis for acceptance testing. Specific requirements are as follows:
1. Clause 12.0.6: Test the opening and closing times, as well as the synchronicity of phase-to-phase and same-phase breaks, to ensure synchronized switch operation and avoid three-phase voltage surges;
2. Clause 12.0.7: Test the opening and closing speeds. This can be waived if no dedicated sensors are available on-site, but it is mandatory for important equipment;
3. Clause 12.0.8: Test the closing-opening (metallic short-circuit) time and reclosing sequence to ensure reliable reclosing operation;
4. Clause 12.0.9: Test the closing resistor’s engagement time and resistance value. Applicable to high-voltage circuit breakers with closing resistors;
5. Additional Requirements: Verify the operating coil’s voltage range to ensure reliable operation within the specified voltage range, avoiding failure to operate or malfunction.
III. Preventive Testing Procedures for Operating Equipment (In-Service Equipment Maintenance) DL/T 596-2021 “Preventive Testing Procedures for Power Equipment”: This standard serves as the basis for annual maintenance and periodic testing of high-voltage switches in operation. It clarifies the items, cycles, pass/fail criteria, and defect judgment criteria for mechanical characteristic tests, covering all voltage levels from 10kV to 500kV and above for circuit breakers and GIS circuit breaker units. It is the core guideline for on-site maintenance personnel conducting tests. Its core requirements are: regularly testing key parameters such as opening and closing time, synchronicity, bounce, and speed; comparing historical data to determine the trend of equipment mechanical performance degradation and proactively identifying potential faults.
IV. Specialized Field Testing Guidelines (Newly Implemented in 2025) DL/T 2890-2025 “Field Testing Guidelines for Mechanical Characteristics of High-Voltage AC Circuit Breakers”: The first specialized mechanical characteristic testing guideline for the power industry, officially implemented on December 30, 2025, completely resolving the previous issues of inconsistent field testing methods and non-standard data processing. This guideline comprehensively standardizes 11 field testing items, testing methods, sensor calibration, data processing, waveform analysis, pass limits, and reporting specifications. It clarifies the testing focus for different types of high-voltage switches (vacuum circuit breakers, SF₆ circuit breakers, and GIS built-in circuit breakers), making it a highly targeted guidance document for current field testing.
V. Specialized Equipment and Instrument Standards 1. DL/T 618 “Field Acceptance Test Procedure for Gas-Insulated Metal-Enclosed Switchgear”: Specifically for GIS combined electrical appliances with built-in circuit breaker modules, this standardizes the specific requirements for mechanical characteristic testing, focusing on standardizing the testing procedures for time, synchronicity, speed, stroke, and operating voltage, adapting to the special structure of GIS equipment. 2. DL/T 846.3-2017 “General Technical Conditions for High Voltage Testing Equipment Part 3: High Voltage Switch Comprehensive Tester”: This standard specifies the technical specifications of high voltage switch mechanical characteristic (dynamic characteristic) testers, including instrument accuracy, number of channels, sensor performance, error range, and anti-interference capability. It serves as the basis for instrument manufacturing and calibration, ensuring the reliability of the test instrument itself.
3. JJG 1120-2015 “High Voltage Switch Mechanical Characteristic Tester”: This national metrological verification regulation clarifies the methods, cycles, and metrological qualification standards for periodic instrument calibration, requiring test instruments to be calibrated at least once a year to ensure the accuracy and traceability of test data.
VI. Core Test Items and Technical Points
Combining DL/T 2890-2025, GB 50150-2016, and other new standards, the testing of high voltage switch mechanical characteristic (dynamic characteristic) covers seven major categories of core items, encompassing all static and dynamic parameters. The testing process must strictly adhere to standardized procedures to ensure data accuracy. (I) Core Test Items
1. Time-related parameters: These include inherent closing time, inherent opening time, opening-closing time (without current interval during reclosing), closing-opening time (metal short-circuit time), and auxiliary contact action time. The core objective is to detect the timeliness of switch action and prevent arc burn-out due to action delays.
2. Synchronization parameters: These include the synchronization difference between three-phase phase closing/opening and the synchronization difference between contacts within the same phase. The core objective is to prevent asynchronous operation of the three-phase switches, which can cause overvoltage surges and damage equipment insulation.
3. Motion speed parameters (core dynamic characteristics): These include the initial closing speed, initial opening speed, average opening/closing speed, and the speed curve throughout the entire process. These are key parameters for evaluating the arc-extinguishing capability of the switch. Abnormal speed can prevent the arc from extinguishing quickly, leading to equipment failure. During testing, displacement sensors must be used to collect contact motion data, which is then processed for noise reduction before calculating the speed parameters to ensure data accuracy. 4. Travel Displacement Parameters: These include total travel, contact distance, overtravel, travel curve, and travel deviation. These directly affect contact pressure and arc extinguishing effect, requiring precise data acquisition using high-precision displacement sensors (linear resistance, laser, etc.) to avoid poor contact due to travel deviation.
5. Dynamic Process Defect Parameters: These include closing bounce time, opening bounce amplitude and time, and contact vibration process. Bounce time is a core hard indicator for vacuum circuit breakers; excessive bounce time exacerbates contact wear and may even lead to contact welding.
6. Operating Coil Electrical Characteristics: This includes the lowest reliable operating voltage, highest non-operating voltage, coil current waveform, and operating voltage range verification of the opening/closing coil. This ensures reliable operation of the coil within the grid voltage fluctuation range, avoiding failure to operate or maloperation.
7. Special Additional Items: For circuit breakers with closing resistors, the closing resistor engagement time and resistance value are tested; for graphite contact circuit breakers, dynamic contact resistance testing is conducted to assess the degree of contact wear. In some scenarios, high-speed imaging and vibration analysis can be combined to troubleshoot complex faults such as contact jamming and buffer failure.
(II) Key Testing Techniques
1. Sensor Selection and Installation: High-precision linear resistance or laser sensors should be prioritized for displacement measurement. During installation, the sensor must be coaxial with the direction of contact movement and securely fixed to avoid errors in stroke and speed measurements due to installation deviations. Time measurements require connection to the switch’s auxiliary contacts to ensure accurate trigger signals.
2. Pre-Test Preparation: Before testing, disconnect the main circuit power supply and ensure proper grounding to avoid induced voltage risks. Perform at least three no-load opening and closing operations on the switch to eliminate mechanical jamming. Formal testing should only begin after the mechanism has stabilized. Calibrate the testing instruments and sensors to ensure accuracy meets requirements.
3. Anti-interference Measures: Strong electromagnetic interference must be avoided during on-site testing. Instrument grounding must be standardized (grounding wire first, then disconnection wire) to prevent induced voltage damage to the instrument. Wavelet denoising processing should be performed on the collected displacement signals to eliminate noise from mechanical vibration and electromagnetic interference, ensuring accurate speed and stroke data. 4. Data Recording and Analysis: Simultaneously record test parameters and motion curves, and save the original data for subsequent comparative analysis; if the data fluctuates significantly (standard deviation > 5%) in multiple tests, even if a single data point is qualified, potential hidden dangers such as loosening of the mechanism should be investigated.
Post time: Apr-22-2026