The next generation leased line telecommunication protection for high voltage substation

Telecommunication circuits and leased lines have been in use for controlling substations for many years. These circuits have usually been engineered according to set standards however recent studies have shown that the parameters used for engineering the telecommunication circuits have various design flaws that may put these circuits. in jeopardy during a local substation fault. The existing protection scheme for SolarI wind and other relevant power generating farms are such that if they lose communication with the local Utility Transmission Station (UTS)I the UTS automatically trips a local breaker and knocks the generation plant off the grid this could mean thousands of dollars in lost revenue for the generation company hence even a minor flaw in the telecommunication circuits can have a significant impact on the substation control system. This case study reviews the challenges of designing these telecommunication circuits for control and monitoring of substations and also reviews the case study performed by Hydro Quebec on the concept of Zone of Influence. In addition this study also proposes an alternate telecommunication model that when implemented will be able to withstand all the challenges of designing a circuits for the high voltage substation.

The next generation leased line telecommunication protection for high voltage substation

Telecommunication circuits and leased lines have been in use for controlling substations for many years. These circuits have usually been engineered according to set standards however recent studies have shown that the parameters used for engineering the telecommunication circuits have various design flaws that may put these circuits. in jeopardy during a local substation fault. The existing protection scheme for SolarI wind and other relevant power generating farms are such that if they lose communication with the local Utility Transmission Station (UTS)I the UTS automatically trips a local breaker and knocks the generation plant off the grid this could mean thousands of dollars in lost revenue for the generation company hence even a minor flaw in the telecommunication circuits can have a significant impact on the substation control system. This case study reviews the challenges of designing these telecommunication circuits for control and monitoring of substations and also reviews the case study performed by Hydro Quebec on the concept of Zone of Influence. In addition this study also proposes an alternate telecommunication model that when implemented will be able to withstand all the challenges of designing a circuits for the high voltage substation.

Measuring anteversion in the femoral neck from routine radiographs

Purpose: To describe a new method for measuring femoral neck anteversion (FNA) that requires only one lateral radiograph of the knee in addition to routine radiographs of the hip for evaluation of total hip replacement; and to compare the proposed method with FNA measurement by means of 3D CT. Material and Methods: In 18 femoral specimens, radiographic examinations of the hip and knee, in three different rotational positions, and one CT examination were made, and the measurements of FNA were compared. Similarly, in 38 patients with 40 total hip replacements, measurements from routine radiographic examinations of the hip and knee and from CT examinations were compared. The accuracy and reproducibility of the FNA measurements produced by this proposed method were calculated. Results: Accuracy and reproducibility were 2° and 2° for the proposed method in the femoral specimen study, and accuracy was 4° in the hip patient study. The proposed method had a minor flaw that was caused almost solely by differences in knee size at inward rotation of the femur. Conclusion: FNA measurement can be made from a routine radiographic examination of the hip and a lateral view of the knee. This method achieves an acceptable level of accuracy and reproducibility.