550 / 2017-05-14 09:55:31

Preliminary Experiment on Development of Non-Contact Measuring Method of Electric Potential Distribution along Interrupting Arc -Simultaneous Measurement of Electric Potential and Radius-

Gas circuit breaker,Arc interruption,Arc potential,Non-contact measurement

Circuit breakers installed in electric power transmission system have nozzles inside the arc quenching chambers. During a current interruption, the state of arc discharge burned in the nozzle shows a rapid transient process and dominates the current interruption performance of the circuit breaker. Therefore, the transient variation in the arc state is an important characteristic for elucidation of the extinction mechanism.
With the above-mentioned background, the purpose of this research project is to develop an arc state measuring method. This paper describes the preliminary experiment to sense an electric potential at a certain location with a contactless monitoring. In this experiment, we used resistors as alternative to the arc. The measuring methodology used in this experiment was based on a contactless sensing by use of straight-line conductors as detectors. The experiment result indicates the facts that the reproduced electric potential reveals very good agreement with the original electric potential. Thus the preliminary experiment are successful of sensing and reproducing the transient potential. The above method also estimated the capacitance C between detectors and a resistor to be 0.33 pF.
Furthermore, we tried estimating the radius of resistors from measured capacitance C. This estimating method is based on the expression of the capacitance C as a function of a resistor radius. The radius of resistor was estimated to be 3.9 mm with the help of the capacitance C estimated to be 0.33 pF. This estimated radius agrees with radius of resistor used in this experiment. The proposed contactless method is therefore capable of estimating the resistor radius.