**8. Conclusion**

Electrical disturbances are close related to power quality, and service quality, and even safety, can be seriously compromised when two linear systems with different electrical

**Part 3** 

**Software Tools** 

feeder schemes are deployed one next to other and have even direct electrical contact between them. Electrical systems in DC and AC railway systems are designed separately, especially considering earthing, and this leads to new problems that weren't faced when old DC lines were design, deployed and operated.

Disturbances are a common issue that an engineer has to face while designing a new facility or system. Disturbances can also appear when the system is already in operation. These systems need to be protected from the effects of the disturbances in the most effective ways. These ways are usually the replacement of equipments (or at least part of them) and the shielding against those electrical disturbances.

In the above sections it has been explained the effects that disturbances from high speed lines can cause on conventional DC lines. A measurement methodology has been proposed. This methodology was used in on site measuring campaigns and their results have been used as a validation of the protecting works carried out before the high speed line comes into operation. The determination of the boundaries between what needs to be changed and what does not need to be changed is a complex problem that must be solved in a cost effective way, but without reducing safety issues.

The different ways of disturbance have been presented and explained so a global vision of the problem can be easily achieved.
