An Open Conductor Condition Monitoring Scheme Using Natural Voltage and Current Disturbances

Undetected open conductor condition is a threat to the safe operation of power plants and industrial facilities. Open conductor condition is especially difficult to detect in a system with certain Y (g) connected primary windings, unloaded transformers. This paper presents a novel open conductor condition monitoring scheme for such systems. The scheme utilizes natural voltage disturbances as test signals and detects the open conductor condition by analyzing the responses of the transformer neutral current to these signals. A detection criterion is established based on sequence domain circuit analysis and on considering background voltage unbalances. Implementation issues, including the hardware requirements and the overall monitoring algorithm, are discussed. Simulation and experimental results prove that the proposed scheme can monitor the open conductor condition effectively.