1. The primary winding of a current transformer is directly connected to the main current loop. If the secondary side becomes open, no current flows through it, while the primary current remains unchanged. This causes the magnetic flux in the core to increase rapidly, leading to saturation. The sudden increase in magnetic flux can generate dangerously high voltages across the open secondary winding, posing serious risks to both personnel and equipment. 2. Common signs of an open circuit on the secondary side of a current transformer include frequent triggering or failure to reset of zero-sequence and negative-sequence current protection devices, unexpected differential protection activation, abnormal ammeter readings with phase currents dropping to zero, reduced active and reactive power meter readings, energy meters running slower than expected, occasional sparks or smoke at the open point, and loud clicking noises from the transformer. These symptoms may not all appear simultaneously, as they depend on which secondary winding is affected and the specific conditions of the open circuit. 3. Steps to address an open circuit on the secondary side of a current transformer: 3.1 Identify which group of secondary windings is affected based on the observed fault symptoms. If the secondary winding used for protection is open, immediately disable any protective devices that might malfunction due to this issue. 3.2 Inspect the secondary circuit components such as relays, instruments, terminal blocks, and other related equipment for visible signs of faults like discharge, smoke, or physical damage. 3.3 If no obvious issues are found, use insulated tools (such as an electric tester) to carefully touch and press terminals and other parts to check for looseness, overheating, or unusual signals. Always ensure the use of appropriate insulated safety equipment, such as insulated gloves, matching the voltage level of the system being tested.
Shanghai Really Technology Co.,Ltd , https://www.really-led.com