SMART GRID SMART GRIDS: say YES to time synchronization, avoid today’s ‘standards’ It seems that there is something wrong with the current system’s interoperability. In the beginning, there were plenty of presentations about how smooth and reliable future operations would be because of interoperability. Today, the initial skepticism of the realists is being realized. Although there were plenty of installations and rollouts realized, no summary results have been announced about the amounts of data transferred (let’s assume more than one reading daily), communication range, real transmission rates, latency, etc. Although no information about results has appeared it is possible to find information about savings within interoperable smart grid (SG) systems. The big surprise is that this information does not come from a single utility, but has been released by the European Commission. If power distributors want to operate in a smart way, it is not enough to have customers with meters equipped with a relay that switches according to tariff. If customers do not connect this functionality with their home infrastructure and do not change consumption behavior, the paper results vary from real life in a dramatic way. The only ones who benefit are thus the meter manufacturers. Paradoxically, recent rollouts have highlighted one fact: interoperable SG systems and the way they are designed today are not able to ensure power network stability and safety in power supply. In order to change this situation, it is necessary to fulfill SG components with reasonable content. One of the most basic characteristics seems to be good synchronization of subordinate PLC networks for communication with meters. This is therefore not a discussion about the intelligence of the device. The important issue here is that devices behave in a coordinated way within the smart grid. They have to have synchronized time, in order to benefit from the predictable behavior of the smart grid, and ensure mutual cooperation of its components. Synchronization will help in the following areas: Time control of the quality for data packet transmissions (TDM = time- division multiplex). The lower the time uncertainty is, the better because single devices on PLC network can transmit data with a lower time gap without mutual disturbance, which leads to increase in network throughput. Exact measurement of immediate voltages and currents. If we analyze these values, we are able to determine real distribution load, and transformers’ supply. Furthermore, if Kirchhoff’s circuit laws for node currents and circuit voltage are applied, we can precisely find out where non-authorized consumption is taking place. Taking into account that non-technical losses reach 10-50% in Europe (increasing in the south-east), it is a really important issue. All meters are able to measure current or voltage. Values measured in a synchronous way can be stored in a FIFO register, and in case the operator needs to analyze problems in a given locality, data stored in the meter (including time stamps) will be transferred to him. Synchronization impulses can be used to indicate the single phases that supply a meter (See Figure 1). It doesn’t matter Figure 1: Principle of communication phase detection via transmission in zero Each phase has its own color. At the exact moment that the voltage goes through zero, the signal is injected into this phase (because of coupling, it is also transmitted into other phases, but only one of them has a signal in zero crossing the appropriate phase voltage). 42 METERING INTERNATIONAL ISSUE – 2 | 2015