Smart grids (SGs) are electrical power grids that apply information, advanced networking, and real-time monitoring and control technologies to lower costs, save energy, and improve security, interoperability, and reliability. Smart sensors (SSs) can provide real-time data and status of the grids for real-time monitoring, protection, and control of grid operations. Sensor data exchange and interoperability are major challenges for the SGs. This paper describes sensing, timing, intelligence, and communication requirements of sensors for the SGs and proposes a general model of the SSs for SGs based on these requirements. Then it illustrates, how the model works with phasor measurement unit (PMU)- and merging unit-based SSs deployed in the SGs with standardized interfaces to support the interoperability of the SSs. Furthermore, to address the interoperability issues, this paper describes sensor interface standards used in the SGs and the need for interoperability testing, and proposes a passive interoperability test method for the SSs to achieve and assure sensor data interoperability. To verify this test method, an interoperability test system for the PMU-based SSs was developed and presented. Interoperability test results of eight commercial PMU-based SSs are provided to show that the proposed interoperability test method works.
