It is the core equipment used in power systems to detect the mechanical performance of high-voltage circuit breakers (such as vacuum switches, SF6 switches, and oil switches).
Its main function is to measure key parameters such as time, speed, travel, and bounce during the opening and closing operations of circuit breakers, to determine whether the switch mechanism is flexible and reliable, and whether there are hidden dangers such as jamming, deformation, or spring fatigue, which directly relate to the safe operation of the power grid.
The following is a detailed technical analysis, core functions, and operating guide for this instrument:
1. Core Test Items and Functions
The instrument can complete multiple mechanical characteristic tests of circuit breakers in one go, with main parameters including:
Table
Test Category Key Parameters Meaning and Description
Time Parameters Opening/Closing Time The time from coil energization to completion of contact action, used to judge the speed of mechanism operation.
Synchronism Phase-to-phase synchronism (difference in operation time among three phases) and same-phase break synchronism (time difference among multiple breaks). Non-synchronism can cause abnormal arc extinguishing or overvoltage.
Reclosing Time The time interval from opening to re-closing, simulating the automatic reclosing function.
Speed Parameters Just-Opening/Just-Closing Speed The average speed at the moment of contact separation/contact (usually in the overtravel segment). This is the most critical indicator, reflecting whether the mechanism has sufficient energy.
Maximum Speed/Average Speed The peak or average speed during the entire motion process.
Travel Parameters Total Travel The total distance of the moving contact from the open position to the closed position.
Overtravel (Contact Travel) The travel by which the contact spring is compressed after closing, representing the contact pressure.
Other Parameters Bounce Characteristics The bounce time, count, and amplitude when contacts touch. Excessive bounce can easily burn the contacts.
Coil Current Waveform Records the current changes of the opening/closing coil to determine whether there is inter-turn short circuit in the coil or jamming of the iron core.
2. Working Principle and Core Technology
Time Measurement: Uses an internal high-precision crystal oscillator (resolution up to 0.01ms or 0.1ms) as the time base, and calculates time by detecting changes in the break signal (on/off).
Travel and Speed Measurement:
Sensor Technology: Converts mechanical displacement into electrical signals through displacement sensors (linear resistive, rotary potentiometer, photoelectric encoder, or acceleration sensor) installed on the moving parts of the switch.
Curve Analysis: The instrument automatically plots travel-time curves (S-t curves) and speed-time curves (V-t curves) to visually display the entire switching action process.
Built-in Power Supply: The instrument has a built-in adjustable DC power supply (usually 30V-270V, current 10A-20A) that can directly drive the opening/closing coil of the circuit breaker without an external operating power supply.
3. Applicable Equipment and Scenarios
Applicable Objects:
Vacuum Circuit Breakers (10kV-35kV): Focus on measuring bounce and overtravel.
SF6 Circuit Breakers (110kV-500kV): Focus on measuring speed and synchronism.
Minimum Oil/Bulk Oil Circuit Breakers: For renovation or maintenance of old equipment.
GIS Switchgear: Requires special sensors.
Application Scenarios:
Commissioning Tests: Before new switches are put into operation, establish baseline data files.
Preventive Tests: Regular maintenance (e.g., once a year) to compare historical data and detect aging trends of the mechanism.
Fault Diagnosis: Troubleshooting after switch refusal to operate or maloperation.
4. Sensor Types and Installation
The choice of sensor directly affects test accuracy. Common types include:
Linear Sensor (Slide Rod Type):
Applicable: Equipment with linear moving parts such as vacuum switches.
Installation: Directly attach or bind to the moving contact rod; direct measurement with high accuracy.
Rotary Sensor (Angle Type):
Applicable: Equipment without exposed linear moving parts such as SF6 switches and GIS.
Installation: Installed on the main shaft or crank arm of the switch, converting the measured rotation angle into linear travel. The transmission ratio coefficient must be input.
Acceleration Sensor (IMU):
Applicable: New high-end testing; no mechanical connection required, displacement calculated through integration, very fast installation, but high algorithm requirements.
5. Brief Operating Procedure
Safety Preparation: Confirm that the switch is de-energized, disconnect the control power, release spring energy (if manual operation is required), and install grounding wires on both ends of the switch.
Wiring:
Break Wires: Connect to the moving and stationary contacts of the switch (phases A/B/C) to detect on/off status.
Sensor: Install the displacement sensor and connect it to the instrument.
Control Wires: Connect to the opening/closing coil (if using internal trigger).
Grounding: The instrument housing must be reliably grounded.
Parameter Setting: On the screen, select the switch type (vacuum/SF6), test items (closing/opening/reclosing), sensor type, and range.
Execute Test:
Click "Close" or "Open", the instrument outputs driving voltage, and the switch operates.
The instrument automatically collects data and displays waveforms.
Data Analysis: Check whether time, speed, and travel exceed limits, whether waveforms are smooth, and whether there is abnormal jitter.
6. Common Fault Diagnosis
Low Speed: May be due to low operating voltage, insufficient spring energy storage, mechanism jamming, or poor lubrication.
Excessive Non-Synchronism: May be due to inconsistent lengths of three-phase connecting rods, deformation of insulating pull rods, or uneven contact wear.
Excessive Bounce: Wear of vacuum interrupter contacts, fatigue of contact springs, or excessive closing speed.
Abnormal Coil Current:
Low Current Peak: Inter-turn short circuit in the coil.
Long Operation Time: High friction or jamming of the iron core.
7. Selection Recommendations
Number of Breaks: Usually choose 6 breaks or 12 breaks (for multi-break high-voltage switches).
Accuracy Requirements: Time resolution recommended at 0.1ms or higher; travel resolution at 0.1mm.
Functional Requirements: It is recommended to choose a model with coil current testing and reclosing function for in-depth diagnosis.
Portability: For field testing, it is recommended to choose a model that is lightweight (<10kg), with built-in printer and lithium battery.
If you need operation videos for specific brands (such as Wuhan Longdian, Huatian Electric, etc.) or standard parameter ranges for certain types of switches (such as VS1 vacuum circuit breakers), please let me know!
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What is the standard for opening and closing time of high voltage switch testers?
