Simulation has played an important role in the reliability, stability and operability of power systems. Power networks are starting to change and new technologies are starting to emerge. New methods of power generation (wind, solar, fuel cells, etc) and power transmission with voltage source converter technology such as Multi-Modular High Voltage DC (MMC HVDC) are being introduced in our networks.. The power network is becoming smarter, with more sophisticated protection and control devices that use high level communication protocols. With the addition of these new features, simulation becomes a critical aspect in the design and operation of the power network. It is becoming increasingly important not only to study isolated areas of the network, but to study the network as a whole. Phasor Measurement Units (PMU) can be deployed at various locations in the power network and can provide real time monitoring of phase and frequency of system voltages and currents. Currently, PMU data is typically used for offline analysis but research is being done to use PMU’s in Wide Area Monitoring Schemes (WAMS) for use in protection and control. PMU data could be used in wide area protection and control schemes to perform actions such as adjust generation, pick up or drop out transmission lines, or shed load. These schemes have the potential to be very powerful and using simulation to understand them and make sure they are secure and reliable is essential.
Several things are required to perform wide area protection and control testing with PMU’s. One is the ability to simulate the power network in real time. To test protection and control schemes using PMU’s, closed loop testing is essential, and closed loop testing can only be performed alongside a simulation that is running in real time. Another critical aspect to the testing of PMU devices is having an absolute time reference shared between both the simulation and the devices under test. If this time reference is not shared between both the simulated and external devices, there will be a phase angle drift between the two sources which may lead to inaccurate results.
The RTDS® Simulator is a real time power system simulator and is used around the world for closed loop testing of protection and control schemes. This paper will show how the RTDS Simulator can be used to test the static and dynamic performance of individual PMU’s. Once the individual PMU’s are tested, further studies can be done looking at wide area protection and control schemes. By using a synchronizaion device, the GTSYNC card, the RTDS Simulator time-step can be synchronized to an external time source (ie. GPS clock). The time reference signal can either be in 1 Pulse Per Second (1PPS) or IEEE 1588 format. In addition, a method for streaming PMU data using the IEEE C37.118 format from the simulation to the outside world using a firmware devoloped for the Ethernet communication card (GTNET-PMU) will be discussed. With the RTDS Simulator, the possibility exists to perform an entirely software simulation using PMU’s and a Phasor Data Concentrator (PDC). Additionally, using an external PDC and PMU’s in combination with simulated PMU’s will be discussed. This paper will show that it is possible to test wide area protection and control schemes using both physical and modelled PMU’s with the RTDS Simulator.
C. Peters, V. Naumov, P. Forsyth, S. Cayres, Presented at XII Symposium of Specialists in Electric Operational and Expansion Planning, Brazil, 2012
KEYWORDS: PMU, PDC, 1 PPS, 1588, RTDS.