Dipendra Rai

Utilizing DFIG-Based Wind Farms for Damping Subsynchronous Resonance in Nearby Turbine-Generators

The paper presents the potential use of supplemental control of doubly-fed induction generator (DFIG)-based wind farms for damping subsynchronous resonance (SSR) oscillations in nearby turbine-generators connected to series capacitive compensated transmission systems. SSR mitigation is achieved by introducing a supplemental signal into the control loops of the DFIG voltage-sourced converter-based back-to-back. The validity and effectiveness of the proposed supplemental control are demonstrated on a modified version of the IEEE second benchmark model for computer simulation of subsynchronous resonance by means of time domain simulation analysis using the EMTP-RV program.

Enhancement of Power System Dynamics Using a Phase Imbalanced Series Compensation Scheme

The paper presents a new series capacitive compensation concept, which enhances power system dynamics. The idea behind the concept is a series capacitive compensation which provides balanced compensation at the power frequency while it results in phase imbalance at other frequency of oscillations. The compensation scheme is a combination of a single-phase thyristor controlled series capacitor (TCSC) and fixed series capacitors in series in one phase of the compensated transmission line and fixed capacitors on the other two phases.

Damping Inter-Area Oscillations Using Phase Imbalanced Series Compensation Schemes

The recently proposed phase imbalanced series capacitive compensation concept has been shown to be effective in enhancing power system dynamics as it has the potential of damping power swing as well as subsynchronous resonance oscillations. In this paper, a comparative effectiveness of two “hybrid” series capacitive compensation schemes in damping inter-area oscillations is evaluated. A hybrid scheme is a series capacitive compensation scheme, where two phases are compensated by fixed series capacitor (C) and the third phase is compensated by either a TCSC or SSSC in series with a fixed capacitor (Cc). The effectiveness of both schemes in damping inter-area oscillations for various network conditions, namely different system faults and tie-line power flows is evaluated using the EMTP-RV time simulation program.

An SSSC-Based Hybrid Series Compensation Scheme Capable of Damping Subsynchronous Resonance

The recently proposed phase-imbalanced series capacitive compensation concept has been shown to be effective in enhancing power system dynamics since it has the potential to damp power swings as well as subsynchronous resonance oscillations. In this paper, the series capacitive compensation concept is investigated for damping subsynchronous resonance oscillations using a static synchronous series compensator (SSSC)-based hybrid series-capacitive compensation scheme. In this scheme, the series capacitive compensation in one phase is created by using a single-phase SSSC in series with a fixed capacitor , and the other two phases are compensated by the fixed series capacitors (C). The validity and effectiveness of the proposed scheme are evaluated on the IEEE first and second benchmark models for computer simulation of subsynchronous resonance by means of time-domain simulation analysis using the Electromagnetic Transients Program-RV program.

Damping subsynchronous resonance using a STATCOM operating in a phase imbalanced mode

This paper describes the potential usage of a STATCOM installed in the power system for damping torsional oscillations induced in turbine generators in series capacitive compensated transmission grids. This is achieved by operating the STATCOM in a phase imbalanced mode for a few seconds after a large system disturbance. The phase imbalanced operation reduces the energy exchange between the electrical and mechanical sides of the turbine generator and, therefore, damps the subsynchronous torsional oscillations resulting from series capacitive compensation. The validity and effectiveness of the proposed scheme is demonstrated using the IEEE first benchmark model for computer simulation of subsynchronous resonance by means of time domain simulation analysis using the EMTP-RV program.

Economic and Simple Power Line Modem Design for the Utility Applications in Micro-Hydro Power Systems of Nepal

This paper introduces a method for indigenous design and construction of a simple and economic low data rate power line modem. The target groups are small power systems of developing countries, like Nepal and its rural power infrastructure consisting of micro-hydro systems. Major focus is placed on how to design and construct a low cost power line modem with a locally researched downscaled technology and components. This work has introduced a power line modem test bed at educational institute of a developing country, Nepal, so that the study and testing of power line communication at local level becomes possible, and at the same time, technology for its application at local level can be made available. The major problems of power line communication like time varying noises, attenuation, and variable impedance characteristics were overcome. The work report detail study of the power line noise and the simplest digital modulation scheme. This paper describes low cost but reliable prototype power line modem design and construction for the purpose of utility applications in micro-hydro power systems. A generalized approach for indicating the applicability of the power line modem in utility application field is also illustrated by reporting the successful testing of computer serial data communication, voice communication, and device control

Impact of imbalanced phase operation of SSSC on damping subsynchronous resonance

The paper investigates the impact of using Static Synchronous Series Compensator (SSSC) in phase imbalanced operation modes on damping subsynchronous resonance in series capacitive compensated transmission grid. Phase imbalance has the potential of reducing the energy exchange between the electrical and mechanical sides of the turbine-generator and, therefore, damps subsynchronous oscillations. The validity and effectiveness of different proposed phase imbalanced modes have been demonstrated on the IEEE first benchmark model by means of time domain simulation analysis using the EMTP-RV program.

Damping power system oscillations using an SSSC-based hybrid series capacitive compensation scheme

The recently proposed phase imbalanced series capacitive compensation concept has been shown to be effective in enhancing power system dynamics as it has the potential of damping power swing as well as subsynchronous resonance oscillations. In this paper, the effectiveness of a “hybrid” series capacitive compensation scheme in damping power system oscillations is evaluated. A hybrid scheme is a series capacitive compensation scheme, where two phases are compensated by fixed series capacitor (C) and the third phase is compensated by an SSSC in series with a fixed capacitor (Cc). The effectiveness of the scheme in damping power system oscillations during system faults at different loading conditions is evaluated using the EMTP-RV time simulation program.

Damping power system oscillations using a hybrid series capacitive compensation scheme

The recently proposed phase imbalanced series capacitive compensation concept has been shown to be effective in enhancing power system dynamics as it has the potential of damping power swing as well as subsynchronous resonance oscillations. In this paper, the effectiveness of a “hybrid” series capacitive compensation scheme in damping power system oscillations is evaluated. A hybrid scheme is a series capacitive compensation scheme, where two phases are compensated by fixed series capacitor (C) and the third phase is compensated by a TCSC in series with a fixed capacitor (Cc). The effectiveness of the scheme in damping power system oscillations for various network conditions, namely different system faults and tie-line power flows is evaluated using the EMTP-RV time simulation program.

Enhancement of power system dynamics using a phase imbalanced series compensation scheme

The paper presents a new series capacitive compensation concept, which enhances power system dynamics. The idea behind the concept is a series capacitive compensation which provides balanced compensation at the power frequency while it results in phase imbalance at other frequency of oscillations. The compensation scheme is a combination of a single-phase Thyristor Controlled Series Capacitor (TCSC) and fixed series capacitors in series in one phase of the compensated transmission line and fixed capacitors on the other two phases.