Design Of On-line Monitoring System For High Voltage Switch Equipment

The medium and high voltage switchgear is an important control device for switching on and off loops,cutting off and isolating faults.It provides a basis for equipment maintenance through the online monitoring of the operating status of high-voltage switchgears,and then to realize the change of periodical maintenance to the state overhaul.High voltage circuit breaker is an important part of high voltage switch equipment,which has the role of protection and control in the power grid.This paper selects the high voltage circuit breaker as the research object,and designs the online monitoring system that related to the high voltage circuit breaker.First of all,the structure and working principle of the broken high-voltage circuit breaker are explained.The main contents of this online monitoring are determined based on the fault statistics and monitoring experience.The Hall current sensor is used to monitor the current of the opening and closing coil,and the normal or fault current waveform is analyzed.The linear displacement sensor monitors the travel of the contact,analyzes the closing and closing speed,the contact displacement and so on.The pressure sensor was used to collect the pressure that generated by the contact at closing,and it monitors the over-stroke pressure of the contact.The open-type hall current sensor collects CT secondary current signal to monitor the breaking current and predict the life of electric contact.This paper analyzes the calculation formula of electric life of different contacts,and uses the relative contact electric life prediction method,and predicts the residual life of the contact head.Secondly,an online monitoring system must be constructed from both hardware and software after completing the overall design of the monitoring system.On the hardware side,it includes the selection of sensors,signal conditioning modules,AD acquisition modules,controller modules,and power module designs.The software is transplanted with the embedded real-time operating system and the software of the hierarchical module management system.In addition,the MCGS configuration software script was used to write the human-computer interaction interface,and it constructs an easy-to-contact graphical interface,displays the circuit breaker status in real time,and alarm the parameters that exceed the threshold.The output signal of the sensor is isolated,amplified and filtered by a corresponding conditioning circuit.Then,the AD7606 chip is used to collect the voltage signal.The STM32 controller module completes the reading and processing of the data,and feeds the processing result back to the humanmachine interactive interface.The module supplies the entire system.Finally,the function of the on-line monitoring system is tested,and the overall functional test is performed after the power module testing and conditioning circuit module tests are completed.The test results are basically the same as the expected design,and the on-line monitoring function of the high-voltage circuit breaker is realized.