DETERMINATION METHOD OF PROTECTION OPERATING TIME OF CONDUCTIVE CONTACT JOINTS OF SWITCHING DEVICES FROM OVERHEAT Russian patent published in 2017 - IPC H02H5/04 

FIELD: electricity.

SUBSTANCE: method includes a deviation control from temperature ceiling of the most susceptible to the overheat contact surface of the conductive contact joint as a part of the switching device and a signal generation, which allows to estimate the time when the contact surface reaches the temperature ceiling. Additionally, this method includes a monitoring mode which measures the value of rectangular impulse of the current and compares a measured value with a predetermined threshold of the experimental or operating rectangular impulse of the current. In case when the current is above its predetermined threshold, the temperature control of the contact surface is carried out in the dynamic monitoring mode on the interval of the contact joint heating time. Further, the temperature values measured during the dynamic monitoring and accessible for direct measurements of the external surface of the contact point, are recalculated into the corresponding temperature values that are not available for direct measurements of the contact surface of the contact connection, and the linear regression equation is derived from the registered indirect contact surface temperature measurements, from this equation the time before the switching device is switched off is determined.

EFFECT: increased accuracy of the detection of the protection operation time.

4 dwg, 2 tbl