Automatic Voltage Regulator Test of Three Gorges Right Bank Hydropower Station

Based on real-time digital simulations(RTDS),a laboratory environment similar to the real-time operation situation of the Three Gorges Hydropower Station is established.Then,the causes for the power fluctuation of the second generator by errors in the rotor rotating speed calculation are found,and the tuning method of the speed related parameters are given.The damping and reverse tuning characteristics of power system stabilizers(PSSs)in the digital automatic voltage regulator(AVR)are compared and investigated in the frequency range of 0.18-1.1 Hz.The efficiency of the proposed tuning method for ensuring power system stability is verified by RTDS.Finally,field tests show the validity of the laboratory test results.

RTDS hardware implementation and simulation of SHAF for mitigation of harmonics using p-q control strategy with PI and fuzzy logic controllers

The main objective of this paper is to develop PI and fuzzy controllers to analyze the performance of instantaneous real active and reactive power （p-q） control strategy for extracting reference currents of shunt active filters （SHAFs） under balanced, unbalanced, and balanced non-sinusoidal conditions. When the supply voltages are balanced and sinusoidal, both controllers converge to the same compensation characteristics. However, if the supply voltages are distorted and/or unbalanced sinusoidal, these controllers result in different degrees of compensation in harmonics. The p-q control strategy with PI controller is unable to yield an adequate solution when source voltages are not ideal. Extensive simulations were carried out with balance, unbalanced, and non-sinusoidal conditions. Simulation results validate the superiority of fuzzy logic controller over PI controller. The three-phase four-wire SHAF system is also implemented on a real-time digital simulator （RTDS hardware） to further verify its effective-ness. The detailed simulation and RTDS hardware results are included.

Modeling methodology and fault simulation of distribution networks integrated with inverter-based DG

The increasing penetration of inverter-based distributed generations(DGs)significantly affects the fault characteristics of distribution networks.Fault analysis is a keystone for suitable protection scheme design.This paper presents the modelling methodology for distribution networks with inverter-based DGs and performs fault simulation based on the model.Firstly,a single inverter-based DG model based on the cascaded control structure is developed.Secondly,a simulation model of distribution network with two inverter-based DGs is established.Then,different fault simulations are performed based on the Real Time Digital Simulator(RTDS).Theoretical analyses are conducted to justify the simulation results,including the equivalent circuit of distribution networks with inverter-based DGs and the solution method for loop currents.