Abstract
Electrical substations transform voltage from high to low, or low to high for distribution and transmission, respectively, and are a critical part of our electricity infrastructure. The state of a substation is continuously measured for monitoring, controlling and protection purposes, using synchrophasor measurements. The IEC 61850 standard defines communication protocols for electrical substations, including transmission of synchrophasor measurements. However, IEC 61850 does not properly address cyber security, leaving this critical infrastructure highly vulnerable to cyber attacks. This paper describes the development and testing of a novel mechanism for delayed integrity check for synchrophasor measurements. The results show that the solution manages to detect when integrity of the synchrophasor transmission is compromised, without adding any delay to the time-critical synchrophasor transmission itself.