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The Unified Power Flow Controller (UPFC) is a novel power transmission controller. The UPFC provides a full dynamic control of transmission parameters, voltage, line impedance and phase angle. This paper presents a useful tool for power utilities engineers to evaluate the application of the UPFC, its impact on their power system and what would be the shunt and series ratings. This paper gives sets of equations for a system including the UPFC and an equivalent two bus power network. A numerical method tested with Matlab has been successfully validated with analog model and EMTP. The Matlab code given in the paper allows to perform fast parametric studies for the application of the UPFC. Keywords: FACTS, UPFC, Matlab

The first part of this three-part report explains the objectives of the task force and the scope of its report [1]. The first part also provides modelling guidelines for the investigation of small-signal torsional oscillations, large-signal shaft transient stresses, turbine-blade vibrations, and fast bus transfer based on the use of digital computer time-domain simulation methods. This paper provides modelling guideline for the analysis of controller interactions, harmonic interactions, and resonance phenomena. Sample lest systems and typical time-domain simulation results for each phenomenon are also provided. Keywords: Controller Interactions; Harmonic Interactions; Resonance; Modelling; Simulation.

The objective of this task force report is to provide a guideline for modelling and analyses of slow (low frequency) dynamics of electrical power systems based on the use of digital 4computer time-domain simulation methods. This report concentrates on small-signal torsional oscillations, large-signal (transient) torsional torques, turbine blade vibrations, and fast bus transfer. This report (1) briefly explains the physical nature of each phenomenon, (2) identifies those power systems components which are either contributors or are adversely affected by the phenomenon, (3) provides time-domain simulation, guidelines and (4) provides sample systems and typical time-domain simulation results. Keywords: Torsional Oscillations; Transient Torques; Turbine Blade Vibrations; Fast Bus Transfer; Modelling; Simulation.

It is common practice to install only phase to ground surge arresters for transformer insulation protection against electrical stresses. However, this may not adequately protect the delta connected transformer phase to phase winding insulation. High phase to phase overvoltages at the transformer terminals, due to capacitor switching, have been reported. This paper describes the excessive phase to phase overvoltages that can also occur due to wave propagation and surge transfer through transformers. This paper points out the need for surge arrester arrangements that protect both, phase to phase and phase to ground transformer insulations. Surge arrester arrangements, selection criteria, installation practices, and application considerations are discussed in this paper.

As an alternative to the conventional shunt capacitor bank installation, a totally new concept of providing reactive power to an electrical power system is presented. A new type of capacitor bank installation called 'bridge' is described. An analytical investigation of the bridge capacitor installation concept and its application in an EHV electrical power system is presented. The technical and economic advantages of the bridge capacitor bank over the shunt capacitor bank are analyzed in the context of the reactive power being directly supplied to an EHV system. A field trial installation at a lower than EHV level (138/69kV) along with some experimental test results are presented in the last part of this paper. A more detailed presentation of the field experience with the trial installation will be covered in a future paper.