Experimental Study on the Transmission of Measurements by Tolerance in SCADA Systems

The study of the existing relationship between a measurement error and the time elapsed since that measurement was taken in the field, a period of time which we will call the datum age, will allow us to learn about its behavior in a supervisory control and data acquisition (SCADA) system. This study has allowed us to know that, in the case of electrical measurements, they quickly reach their maximum error value because of their age. Therefore, it is not necessary to send measurements to the control center at small intervals: it is possible to wait a given time without having a higher associated error. After getting these results, we have done an experimental study about electrical measurements, in which these measurements are sent to the control center only if they exceed a given percentage of the former measurement, what we call measurement tolerance. In this paper, it has been experimentally proved that this send-by-tolerance method significantly reduces the transmission channel load, so the system can benefit from this because the bandwidth can be reused by more remote units, as well as performance of the existing ones is improved.