Principle And Engineering Practice Specification For Opening And Closing Sequence Control Of Drop-out Type Fuses
The opening and closing operation sequence of High Voltage Fuse is the core technical link to ensure the safe operation of the power system. Its control logic involves the multi-dimensional coordination of electromagnetic transient process, mechanical dynamic response and insulation recovery characteristics. This paper combines the operation data of 35kV and below distribution network to systematically explain the technical specifications and engineering implementation points of the operation sequence.
1. Electromagnetic basis of opening and closing sequence
... ... ... 2. Standard opening operation process
(1) Middle phase priority: Use a dedicated insulating operating rod (J ≥ 100kN·m bending strength) to pull off the middle phase melting tube at an elevation angle of 60°
(2) Downwind side phase: After an interval of 45 seconds, disconnect the leeward side phase according to the airflow direction
(3) Upwind side phase: Monitor the insulation resistance of the disconnected phase > 500MΩ and complete the final disconnection
... Dynamic parameter control
(1) Opening speed: 0.6-0.8m/s (error ±0.05m/s), ensuring contact separation time <3ms
(2) Arc energy: limited to 18-22kJ, with ZnO voltage limiter (U1mA=1.3Ur)
(3) Mechanical locking: After the opening is in place, the droop angle of the melting tube > 85° triggers the position sensor
Step control
... Mechanical stress balance
(1) Middle phase closing force: operating lever force angle 45°±5°, contact pressure＞180N
(2) Side phase synchronization: two-phase closing time difference <80ms to avoid circulating current
(3) Dynamic monitoring: install MEMS vibration sensor (sampling rate 10kHz), detect contact collision acceleration <15g
... The operation interval is extended to 120 seconds/phase, with RC absorption device (C=0.15μF, R=47Ω).
... ...
Servo drive system
Servo drive system
... ... Based on ANSYS Maxwell, an electromagnetic-mechanical coupling model is established to preview the dynamic response under different operation sequences. An intelligent station application shows that virtual debugging reduces the actual operation error rate by 72%.
VI. Analysis of typical operating accidents
A 35kV line mistakenly separated the side phases first, causing the middle phase overvoltage to break through the arrester (Upeak=98kV). After the accident, a phase sequence locking device was installed, and the logic judgment time was shortened to 18ms.
... ... VII. Conclusion
... The operation and maintenance unit should conduct mechanical property tests regularly (once every two years), focusing on checking the synchronicity of opening and closing (ΔT < 50ms) and the deviation of contact movement trajectory (< 2°).
