The purpose of the ratio test is to verify the accuracy and proper operation of the current transformers (CTs) that provide the secondary currents to the relays. By injecting a known current into the primary side of the CTs, the ratio test can determine if the CTs are providing the correct ratio of current to the relays.
It is the common method that performs the ratio test is through current primary injection. This involves injecting a calibrated current into the primary side of the CTs and measuring the resulting current on the secondary side. By comparing the injected current to the secondary current, the ratio test can determine if the CTs are accurate and within acceptable limits.
Performing the ratio test by current primary injection is a crucial step in maintaining the reliability and accuracy in power systems. By following the proper procedures and using the right equipment, the ratio test can help identify any issues with the CTs and ensure the proper operation of the protective relay system.
Wuhan Huayi Electric power produces the primary current injection tester, which is portable with trip time and display the ratio and other parameters.
Easy to operate and high performance. It is an idea test equipment for maintenance the power system.