Time filter

Source Type

Winnipeg, Canada

Pham J.-P.,University of Manitoba | Denboer N.,TransGrid Solutions Inc. | Lidula N.W.A.,University of Manitoba | Perera N.,University of Manitoba | Rajapakse A.D.,University of Manitoba
2011 IEEE Electrical Power and Energy Conference, EPEC 2011 | Year: 2011

A pattern classification technique for fast detection of power islands in a distribution network is implemented and tested. It utilizes voltage and current transient signals generated during an islanding event to detect the formation of the island. A Decision Tree classifier is trained to categorize the transient generating events as 'islanding' or 'non-islanding'. It involves two basic stages of signal processing to extract the required feature vectors for the classification. The first stage involves signal filtering and in the second stage signals are processed by rectifying, summing, and low-pass filtering to get the energy content in the three phases during a selected time-frame. Analog filters, rectifiers, adders and micro-controllers complete the implementation. The performance of the design was tested with signals generated using a real-time waveform playback instrument. A simple radial medium voltage distribution system with single distributed generator was simulated in PSCAD/EMTDC to obtain the transient waveforms. The experimental and simulation results give comparable results showing high accuracy in detecting islanding events very fast. © 2011 IEEE.

Arunprasanth S.,University of Manitoba | Annakkage U.D.,University of Manitoba | Karawita C.,TransGrid Solutions Inc. | Kuffel R.,RTDS Technologies Inc.
IEEE Transactions on Power Delivery | Year: 2016

This paper proposes a robust frequency-domain method to tune the d-q decoupled control system used in Modular Multilevel Converter-type Voltage Source Converter (MMC-VSC) systems. A linearized state-space model of the MMC-VSC system is developed and used to calculate the stability-related frequency-domain attributes. The controller design problem is formulated as an optimization problem. In this paper, the simulated annealing optimization technique is applied to find the proportional-integral (PI) controller parameters that give desired damping for the oscillatory modes and desired values for decaying exponential modes. The efficacy of this method is tested on the electromagnetic transient model of a two-terminal MMC-VSC system on the real-time digital simulators, and the results are provided in this paper. Finally, tuned controller parameters for different ac system strengths are discussed and it is shown that this mathematical model is suitable to tune the PI-controller parameters for MMC-VSC systems connected to strong as well as weak ac networks. © 2015 IEEE.

Dissanayaka A.,University of Manitoba | Annakkage U.D.,University of Manitoba | Jayasekara B.,TransGrid Solutions Inc. | Bagen B.,Manitoba Hydro
IEEE Transactions on Power Systems | Year: 2011

This paper presents a linearized technique to determine a risk-based index for dynamic security. The method is an extension to an existing technique in which the risk of steady state security is calculated using the mean and variance of load uncertainty. The proposed method is applied to calculate the risk indices for the IEEE New England 39-bus test system. The results obtained from the proposed method are validated against those estimated by Monte Carlo simulation. Both approaches produce virtually the same results for small load deviations. © 2011 IEEE.

Karawita C.,TransGrid Solutions Inc. | Annakkage U.D.,University of Manitoba
IET Conference Publications | Year: 2010

A linearized model of an HVDC system is presented in a control block diagram form. The converter models (rectifier and inverter), DC transmission system, phase lock oscillators (PLOs) and the HVDC controllers are included. The control block diagram model of HVDC system simplifies, in understanding and modelling, the complex operation of the HVDC system. The model can be used in small signal stability assessment to analyze subsynchronous frequency HVDC interactions such as generator-turbine torsional interactions. Furthermore, the model can be easily implemented in a software environment such as Simulink for response analysis, control tuning and other educational purposes.

Suriyaarachchi D.H.R.,University of Manitoba | Annakkage U.D.,University of Manitoba | Karawita C.,TransGrid Solutions Inc. | Jacobson D.A.,Manitoba Hydro
IEEE Transactions on Power Systems | Year: 2013

This paper presents a comprehensive analysis of sub-synchronous interactions in a wind integrated power system to understand and mitigate them. The proposed procedure has two steps. In the first step, a frequency scan is performed to determine the presence of resonant frequencies in the sub-synchronous range. In the second step, a detailed small signal analysis is performed. Participation factors are used to identify the state variables that are involved in the interaction, and the controllability indices are used to determine the mitigation method. It is shown that the sub-synchronous interaction present in Type 3 wind turbine-generators connected to the grid through series compensated lines is an electrical resonance between the generator and the series compensated line which is highly sensitive to the rotor side converter current controller gains. © 1969-2012 IEEE.

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