PMU performance requirements and validation for closed loop applications

Wide Area Measurement Systems (WAMS) are increasingly used to observe the static and dynamic performance of power systems. Synchronised phasor measurements are also a valuable wide-area input to control and protection schemes. It is important that PMUs perform correctly for the various purposes that the data is used for. Standard and type testing is valuable, but it is also necessary to have the capability to perform specific tests for the monitoring and control applications. In particular, where phasor measurements are applied to control schemes, it is important to assess the requirements and impact of the PMU data quality on the control scheme. This paper details the findings of the authors in the field of practical design and implementation of PMU´s (Phasor measurement Units) in a system. The required response of PMU´s under various types of system disturbances is examined through simulation of disturbances in a large power system. The response of the PMU required for power system stability applications is examined and tested for frequency variations and presence of harmonics in the system. The paper presents the simulation setup and the thought process behind creating a virtual setup for developing and testing PMU applications. This simulation environment allows testing of the system response with closed loop control involving phasor measurements. This approach can be used to prove the control scheme, and also to develop the requirements for the PMU speed, accuracy and communications latency for correct operation of the schemes under test.