Current transformer secondary side open circuit fault cause judgment and treatment - Database & Sql Blog Articles

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1. The primary winding of the current transformer is directly connected to the primary current loop. When the secondary side is open, the secondary current is zero, and the primary current does not change, so that the magnetic flux in the core increases sharply to a saturation level. This sharp magnetic flux creates high voltages in the open secondary winding, directly jeopardizing the safety of the person and equipment.
2. The secondary open circuit of the current transformer includes: the zero-sequence, negative-sequence current-starting protection device starts frequently, or cannot be reset after starting; the differential protection starts or malfunctions; the ammeter indication is abnormal, and the phase current indication decreases. To zero; the active and reactive power meter indications are reduced, the energy meter is slow; the open circuit points may sometimes have sparks or smoke; the current transformer has a large click.
Some of the above phenomena do not necessarily occur at the same time, depending on which load is applied to the secondary winding of the open circuit and the specific conditions of the open circuit.
3. Current transformer secondary side open circuit processing
3.1 According to the fault phenomenon, it is judged which group of secondary windings is open. If the secondary winding for protection is open, apply immediately to deactivate the protective device that may be malfunctioning.
3.2 Check the open circuit winding power supply secondary circuit equipment (relay, instrument, terminal block, etc.) with or without discharge, smoke and other obvious open circuit phenomenon.
3.3 If no obvious fault is found, use an insulating tool (such as an electroscope) to gently touch and press the terminal and other parts to observe the abnormal phenomenon such as looseness, fire or signal action. In order to carry out this inspection, it is necessary to use insulated safety appliances (such as insulated gloves, etc.) with matching voltage levels and tests.