Performance Evaluation Of Transmission Line Based On SCADA

As an important component of power grid, the security and reliable operating of overhead transmission line has a great meaning for power grid operation. Therefore, the transmission lines'behavior observation, maintenance and repair have been being highly valued. Currently, in order to save manpower and resources, the transmission line monitoring means is becoming diversified, and a lot of assessment methods have appeared. Although the direct monitoring of transmission line behavior has a certain effect, it is costly and difficult to grasp transmission lines behavior and progressive changes effectively. In fact, the information of the power grid included in SCADA system is quite complete, and plays a significant role in monitoring the operating performance of the network. So, whether the information can be used as a basis for transmission line performance evaluation? This is the question this dissertation attempts to explore and study. Based on the analysis of relationship between transmission line structure and operation performance, the expresstion of transmission line structure and operation measurements can be reflected by the generalized voltage-ampere characteristic. Performance indicators are given to achieve progressive evaluation of transmission line. It can be seen that the study has important meaning.Firstly, the definition of transmission line structure and operation performance is given. Then, influencing factors and relationship between the two performances are analyzed. Three-phase transmission line model is established, and the influencing factors of the transmission line structure parameters are analyzed on the basis of admittance equation then the corresponding qualitative or quantitative expression is obtained. Impedance and admittance are proved to be the appearance forms of transmission line structure performance and play a decisive role in the evaluation of structure performance which shows the transmission line operation nature. Thus, based on the generalized voltage-ampere characteristic, the relationship between transmission line structure and operation performance is analyzed to provide basis for structure performance evaluation. Secondly, starting from the relationship between structure and operation performance, according to generalized voltage-ampere characteristic and its deduction, performance indicators expressed by SCADA information (electric measurements) are extracted and classified by dominant factor. Relationship between performance indicators and electrical measurements is analyzed. The containment relationship among performance indicators is also analyzed to provide theoretical support for the transmission line performance evaluation.Finally, in real-time environment, the data features of performance indicators are analyzed based on stochastic process theory according to the changing and procedurally-replicating SCADA information. Considering the variation trend and mutual influence law of performance indicators, performance evaluation rules are proposed on the fundamental basis that structure performance changes smoothly and progressively. Then the basic architecture of the performance evaluation system is presented. A transmission line in a Shandong area power grid is taken as an example to prove the feasibility of the evaluation method.Overall results show that, the causal law analysis of transmission line structure and operation performance can be achieved by mining SCADA information effectively. The trend in transmission line operation can be found or identified by an incremental approach. That provides new ideas for the transmission line performance evaluation and information for condition-based maintenance. Thus, this is a useful exploratory study.