Research And Design Of Vacuum Interrupters Vacuum Degree On-line Detection System

Vacuum interrupter（VI） is a powerful equipment which is widely used in electric power transmission and distribution system. As the medium, vacuum has its unique characteristics of the arcing and prevent leakage arc to ensure the safe operation of the equipment. And the gas pressure within VI has a direct effect upon the properties of vacuum circuit breaker. With the development of intelligent network and t the system of equipment testing rules, the change of the online detection of vacuum degree becomes the new target of equipment with the power grid intelligent switch, so the study of vacuum degree on-line detection is also an indispensable subject, which has its engineering value.Firstly, this paper analyzes the structure of VI and influencing factors of vacuum change, and detail summarizes domestic and international related pressure detection technology of high voltage switch vacuum degree, and analyzed all kinds of measurement principles and their merits and demerits; Secondly, studies and analyzes the formation of VI metal shield potential and the relationship between VI metal shield and vacuum degree;Then designs a set of VI vacuum degree on-line detection system on the basis of the metal shield potential detection method.The on-line detection system design mainly includes the sensor probe, signal processing circuit, control circuit, radio transmission circuit and display circuit. The design is based on TMS320F2812 DSP and STM32F103 micro-controller system; it completed the design of signal processing circuit which included an over-voltage protection, low pass filter, programmable amplifier, RMS-DC circuit and coupling capacitance sensing probe was developed to accomplish the vacuum interrupter metal shield AC potential acquisition; Realize the voltage RMS AD sampling and vacuum pressure is obtained by the formula to calculate; Through the wireless communication module nRF24L01 sent the sampling voltage and vacuum pressure data to the remote PC display, storage, to solve the interference of electromagnetic for data transmission. System software design using modular programming ideas, complete the related program design,which is include TMS320F2812 control MCP41010 program and NRF24L01 send program; ADC conversion program, STM32F103 control NRF24L01 receiving program and LCD display program design.Finally, builds a set of vacuum calibration system, and obtained the curve of the relationship between the voltage output of the sensor and the vacuum degree by thecalibration system and synthesizes it into empirical formula. The empirical formula is built into the measurement controller through software programming language, which realizes the vacuum degree detection. The designed system can test the vacuum degree measurement in the range of 10^-2-2Pa, which can meet the practical requirements of engineering.