Frequency Control in Power Systems with High Penetration of Power Electronics interfaced Power Sources

  • Mingyu Sun

Student thesis: Phd


The increased penetration of Power Electronics (PE) interfaced power sources is significantly affecting the dynamic performance of the existing power system. These changes are such that in the future it may no longer be possible to guarantee the security of operation, especially for frequency control. The increased level of uncertainties, particularly the reduction of and variation in system inertia that will be faced in the future, must be resolved through the use of adaptive online solutions to ensure system security and the introduction of novel technologies. This technology is based on the extensive usage of novel sensors and Information and Communication Technology (ICT). The solutions proposed in this thesis are based on the application of Synchronised Measurement Technology (SMT) and Wide Area Monitoring, Protection and Control (WAMPC) type solutions. The objective of this thesis is to analyse the challenges for existing frequency control methods and to create new frequency control methods. The intent is to contribute to the developments of new corrective control of frequency for future power systems in two ways: online estimation of system inertia and swing equation based adaptive frequency control. The research presented includes a method for online estimation of the system inertia using wide area measurements. The availability of synchronised measurements will allow it to replace the traditional methods. With estimated system inertia, a decentralised under frequency load shedding scheme is proposed to adaptively adjust load shedding amount using local measurements. This is particularly effective before a complete WAMPC scheme can be established in the system and can act as an important protection scheme in parallel with future WAMPC based frequency control scheme. Furthermore, a fast frequency control scheme using WAMPC is then presented, which uses real-time frequency data from PMUs and determines the required responses. The system takes into account the impact of the frequency event on different parts of the network and allocates responses at a regional level. The characteristics and capabilities of connected resources are considered so that a coordinated and optimised response is dispatched immediately following the event. A high-fidelity Real Time Digital Simulator (RTDS) based real-time simulation testbed used for the validation process is also constructed and presented in this thesis to facilitate the validation of novel techniques for power system protection and control. Methods proposed in this thesis are validated using the testbed through Controller-In-the-Loop (CIL) and Controller Hardware-In-the-Loop (CHIL) testing techniques.
Date of Award31 Dec 2020
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorHaiyu Li (Supervisor) & Vladimir Terzija (Supervisor)


  • frequency control
  • power system

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