Improvement of insulation resistance measurement accuracy during spacecraft power system tests

Modern spacecraft power systems features connection of ground power bus with satellite body, which aims to im- prove noise immunity and protect power system and its modules from possible breakdown due to static charge accumu- lation on spacecraft body, which can lead to high voltages between spacecraft body and power system sensitive elec- tronic components. The main disadvantage of this solution is a possibility of short circuit between any high voltage power system bus and spacecraft body, which can easily lead to breakdown of power system modules, payload elements and wire harness, making satellite dysfunctional. To prevent such malfunction situations during terrestrial testing and spacecraft lifetime the authors developed automatic insulation resistance continuous monitoring device based on con- tactless leakage current measurements on every spacecraft power system line. In the device magnitude of measured differential currents can be very low, in order of microamperes. Modern magnetic modulation based leakage current sensors has a major flaw which leads to great influence of high current magnetic field on a measurement result and highly increased insulation resistance measurement error. The authors has studied magnetic modulation based leakage current sensors, proposed the method of error compensation for studied measurement errors using additional current sensor, developed and tested device using proposed principles and done experimental study of device development version. Developed automatic insulation resistance continuous monitoring device implemented on the laboratory spacecraft power system test bench, at present the authors are preparing additional experiments to improve methodo- logy, quality, accuracy and convenience of recently introduced insulation resistance measurement methods.