To improve the accuracy of current transformer (CT) secondary circuit disconnection (abbreviated as CT disconnection) identification in busbar protection

thereby preventing high-resistance grounding faults from being misidentified as CT disconnection

a busbar protection CT disconnection identification method is proposed based on current dynamic trajectory characteristics. First

the current characteristics under high-resistance grounding faults and CT disconnection conditions are comparatively analyzed

identifying their significant differences. On this basis

a dynamic trajectory is constructed using the reference sinusoidal currents and the actual sampled currents from the protection equipment. By evaluating the similarity between this trajectory and the generalized ellipse

reliable distinction between high-resistance grounding faults and CT disconnection is realized. Then

the influences of abnormal current waveforms

DC components

asynchronism

light load and other factors on the proposed criterion are analyzed. Finally

a typical 500 kV power system is built via the RelaySimTest simulation software to simulate high-resistance grounding faults to verify the effectiveness and feasibility of the proposed method. The results show that the proposed criterion exhibits excellent robustness under the aforementioned influencing factors

and can effectively distinguish high-resistance grounding faults from CT disconnection even under light load conditions.