Product Overview
Currently, the conventional QJ44 type double-arm DC bridge is commonly used in power systems for measuring contact resistance. However, the test current of this bridge is only at the mA level, making it difficult to detect defects such as reduced cross-sectional area of circuit conductors. When measuring the contact resistance of high-voltage switch conductive circuits, due to the influence of oil film and oxide layer between contacts, the measured value is several times larger, failing to truly reflect the contact resistance value. To this end, the Ministry of Electric Power standard SD301—88 "Regulations for Handover and Preventive Tests of AC 500KV Power Equipment" and the new edition of "Regulations for Preventive Tests of Power Equipment" stipulate that the measurement current for contact resistance of circuit breakers and disconnectors should not be less than DC 100A, to ensure accurate test results. This product is designed based on the latest Chinese electric power execution standard DL/T845.4-2004, combining high-frequency switching power supply technology with digital circuit technology. It is suitable for measuring the loop resistance of switch control equipment. The test current adopts DC 100A and 200A recommended by national standards. It can directly measure the loop resistance at a current of 100A, or directly measure the loop resistance at a current of 200A, with the final test results displayed digitally. This instrument features accurate measurement and stable performance, meeting the requirements for on-site high-voltage switch maintenance by power and supply departments and loop resistance testing in high-voltage switch factories.
