Self-tuning regulator design for nodal voltage waveform control in electrical power systems

The paper presents a systematic approach to self-tuning regulator design for nodal voltage waveform control in electrical power systems by means of shunt power electronic devices (SPEDs). The proposed approach is structured into three main tasks. In the first one, starting from the sampled measurements of the nodal voltage and of the current, which is injected by the SPED into the power system, a Kalman filtering technique is adopted to estimate the voltage and current phasors at fundamental and harmonic frequencies. These estimates are then used by the second task for the on-line parameter identification of the Thevenin equivalent circuits that represent the electrical power system at each phasor frequency. Finally, in the third task, the closed-loop voltage regulator is adapted so as to satisfy the design requirements expressed in terms of desired closed-loop pole locations. After illustrating the algorithms and the design criteria related to each of the mentioned tasks, the proposed approach has been applied to the design of a self-tuning regulator for the control of an active filter (the SPED) in an IEEE-test industrial electrical system. The results obtained by accurate numerical simulations confirm the validity of the proposed approach.