Detection of weak bus through Fast Voltage Stability index and inherent structural characteristics of power system

Modern power system is large, complex and characterized by continuous increase in electrical load demand. As a result, the system is stressed to operate closer to stability limit and this may result in voltage collapse. Therefore, it becomes imperative to implement techniques for detecting collapse in bus bar or lines before its occurrence in the power system. This paper presents the concept of inherent structural characteristics of power networks and the power flow based technique of the Fast Voltage Stability index (FVSI). To detect the weakest line with respect to a bus using the conventional based approach of the Fast Voltage Stability Index (FVSI), a repetitive power flow solution is performed while varying the reactive power load at a particular load bus. The line or bus that has its FVSI closest or equal to 1 is identified as the weakest line or bus. The concept of inherent structural characteristics of the power network is formulated based on the fundamental circuit theory laws which employs the use of eigenvalue decomposition method in predicting the bus liable to instability. The two approaches are then compared. The result obtained shows that, weak bus is better detected through the concept of inherent structural characteristics of power network as it saves time and does not involve performing the time consuming traditional load flow before the weak bus is known.