"Frequency and Angle Stability of AC Systems Connected with DC Links"
Prashant Agnihotri (Ph.D. student)
Supervisor: Dr. Aniruddha Gole
Aim of Project
The objective of this research is to use fast HVDC controllers to damp the power swings in the interconnected AC network. Wide area measurement signals will be used to get the system-wide information of the network to improve the observability of the critical modes of oscillation and controllability by efficient damping.
Description of Project
An HVDC link embedded in an AC network can improve its angular and frequency stability by fast control. There are many existing schemes such as the Pacific Intertie which modulates the DC power to damp power swings in parallel ac lines and the Eel River scheme for frequency stabilization of the islanded ac systems. In order to damp the oscillations effectively, the feedback signals should be chosen carefully. The preferred approach is to use the local signals, such as the frequency of the adjacent generator bus, frequency deviation between the sending and the receiving station, or the derivative of the power flow signal through the parallel AC line. Appropriate control functions are used to process these signals to modulate the DC power.
Some problems observed in the past were noise, and harmonics in the feedback signals. These may result in inefficient damping of some of the modes under consideration and may excite other unwanted modes of oscillation. Recently, with the advancement of the Phase Measurement Unit (PMU) technology, signals can be transmitted from the remote locations which may make the damping controllers more effective. This research will concentrate on obtaining system-wide information of the power systems network using wide area measurement signals in order to improve the observability of the critical modes of oscillation. Later, this information will be utilized to improve the controllability of active and reactive power modulation through the DC link to efficiently damp the power swings in the AC network.
Accepted/Published Papers
None at this time.