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In the current research, we report on a peer feedback system for supporting student teamwork skill development during post-secondary education. The peer feedback system is part of a larger suite of assessments at ITPmetrics.com. This is a free assessment-based system that allows team members to provide round-robin ratings of each member's effectiveness in the team on five dimensions (communication; commitment; foundation of knowledge, skills and abilities; emphasising high standards; and focus), as well as provide anonymous written feedback to supplement the numeric scores. Team members have access to a dashboard where they can complete the assessment and store assessment reports generated from their peers' ratings. We summarise data from student learning teams suggesting that peer ratings are reliable (internally consistent, unidimensional and inter-rater correlated; n > 85,000). Recommendations for implementation are provided with respect to pre-briefing, debriefing, and assessment schedules.

A multistage identification algorithm for dynamic power system load models is proposed in this paper. The multistage approach is used to address the nonconvexity of the identification problem. Initial stages are used to find good preliminary estimates for the parameters of the model. Specifically, the initial stages are as follows: Equations for dynamic power system loads are discretized using the zero-order hold method and then approximated with a 2nd-order polynomial NARMAX model. Finally, an extended least squares approach is used to estimate the parameters of the NARMAX model, from which initial estimates for the parameters of the original model are obtained. In the final stage, the values found in the initial stages are used as the starting point for a Levenberg-Marquardt optimization routine that computes the optimal parameters. Numerical experiments using data from both simulated and real systems illustrate the computational complexity and accuracy of the proposed algorithm. Curve-fitting experiments are used to justify the polynomial NARMAX approximation. Index Terms--Power system load modeling, system identification.

In a deregulated electricity industry, new concerns have emerged regarding the quality of the power supply as companies tend to focus on their own objectives and interests. One main concern regarding power-supply quality is voltage fluctuation. Voltage fluctuations are defined as repetitive or random variations in the magnitude of the supply voltage. This paper addresses a method for monitoring the voltage flicker using state estimation (FSE). A test system is used to characterize the new algorithm in which parameter inaccuracies have been considered. The new algorithm can be used by operators as well as distribution companies to monitor the flicker severity throughout the network. Index Terms--Power quality (PQ), state estimation, voltage flicker.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ejor.2005.01.021 Byline: William Rosehart, Codruta Roman, Laleh Behjat Keywords: Energy; Optimization; Voltage collapse; Optimal power flow Abstract: In this paper, a detailed analysis of the use of optimization techniques in the study of voltage stability problems, leading to the incorporation of voltage stability criteria in traditional Optimal Power Flow (OPF) formulations is presented. Optimal power flow problems are highly nonlinear programming problems that are used to find the optimal control settings in electrical power systems. The relationship between the Lagrangian Multipliers of the OPF problem and the classification of the maximum loading point level of the system is given. Finally, the paper presents a sequential OPF technique to enhance voltage stability using reactive power and voltage rescheduling with no increase in real (active) generation cost. Author Affiliation: Department of Electrical and Computer Engineering, University of Calgary, 2500 University Drive, N.W., Calgary, AB, Canada T2N 1N4

This paper proposes a Cumulant Method-based solution to solve a maximum loading problem incorporating a constraint on the maximum variance of the loading parameter. The proposed method takes advantage of some properties regarding saddle node bifurcations to create a linear mapping relationship between random bus loading variables and all other system variables. The proposed methodology is tested using a sample system based on the IEEE 30-bus system using random active and reactive bus loading. Monte Carlo simulations consisting of 10 000 samples are used as a reference solution for evaluation of the accuracy of the proposed method. Index Terms--Cumulants, numerical optimization, nonlinear programming, probabilistic methods.

Modern integrated circuit design involves the layout of circuits consisting of millions of switching elements or transistors. Due to the sheer complexity of the problem, optimizing the connectivity between transistors [...]

This paper proposes a mathematical program with complementarity constraints to better model the relationship between the base, or current, operating point and the maximum loading point in a power system when solving maximum loading problems. Index Terms--Complementarity problems, mathematical programs with complementarity constraints, optimal power flow, voltage stability.

This paper introduces the cumulant method for the probabilistic optimal power flow (P-OPF) problem. By noting that the inverse of the Hessian used in the logarithmic barrier interior point can be used as a linear mapping, cumulants can be computed for unknown system variables. Results using the proposed cumulant method are compared against results from Monte Carlo simulations (MCSs) based on a small test system. The Numerical Results section is broken into two sections: The first uses Gaussian distributions to model system loading levels, and cumulant method results are compared against four MCSs. Three of the MCSs use 1500 samples, while the fourth uses 20 000 samples. The second section models the loads with a Gamma distribution. Results from the proposed technique are compared against a 1000-point MCS. The cumulant method agrees very closely with the MCS results when the mean value for variables is considered. In addition, the proposed method has significantly reduced computational expense while maintaining accuracy. Index Terms--Cumulants, optimal power flow (OPF), probabilistic optimization.

The rapid growth of inter-regional trading among electricity markets requires the development of new market-oriented mechanisms for the inter-regional congestion management of such trading. In this paper, we deal with the operation of power systems consisting of several interconnected electricity markets. We propose an alternative approach to inter-regional trade that avoids the flaws of forward markets with explicit auctioning of interconnections capacities. We propose the integration of a forward market with a balancing (spot) market for inter-regional exchanges based on nodal pricing. The interaction of transmission system operators (TSOs) belonging to adjacent markets is efficiently taken into account through a decentralized optimal power flow (OPF), which is solved by interior point methods. Index Terms--Congestion management, interior point methods, inter-regional trade, optimal power flow.

In this paper, new optimal power flow (OPF) techniques are proposed based on multiobjective methodologies to optimize active and reactive power dispatch while maximizing voltage security in power systems. The use of interior point methods together with goal programming and linearly combined objective functions as the basic optimization techniques are explained in detail. The effects of minimizing operating costs, minimizing reactive power generation, and/or maximizing loading margins are then compared in both a 57-bus system and a 118-bus system, which are based on IEEE test systems and modeled using standard power flow models. The results obtained using the proposed mixed OPFs are compared and analyzed to suggest possible ways of costing voltage security in power systems. Index Terms--Bifurcations, goal programming, interior point methods, multiobjective optimization, optimal power flow, voltage collapse.

In this paper, detailed generator, exponential load, and static volt-ampere-reactive (VAR) compensator models are incorporated into traditional and voltage-stability-constrained optimal power-flow problems to study the effect that the different models have on costs and system-load ability. The proposed models are compared to typical models by means of a detailed analysis of the results obtained for two IEEE test systems; interior point methods are used to obtain numerical solutions of the associated optimization problems. Index Terms--Interior point methods, modeling, optimal power flow, voltage stability.

This letter introduces the cumulant method for the probabilistic optimal power flow (P-OPF) problem. The proposed adaptation of the cumulant method to the P-OPF problem is given. Index Terms--Cumulants, optimal power flow, probabilistic optimization.

A mathematical program with complementary constraints is used to better model the relationship between the current or base operating point and the maximum loading point in a power system when solving the maximum loading problem. Index Terms--Complementarity programming, stability.

In the current research, we report on a peer feedback system for supporting student teamwork skill development during post-secondary education. The peer feedback system is part of a larger suite of assessments at ITPmetrics.com. This is a free assessment-based system that allows team members to provide round-robin ratings of each member's effectiveness in the team on five dimensions (communication; commitment; foundation of knowledge, skills and abilities; emphasising high standards; and focus), as well as provide anonymous written feedback to supplement the numeric scores. Team members have access to a dashboard where they can complete the assessment and store assessment reports generated from their peers' ratings. We summarise data from student learning teams suggesting that peer ratings are reliable (internally consistent, unidimensional and inter-rater correlated; n > 85,000). Recommendations for implementation are provided with respect to pre-briefing, debriefing, and assessment schedules. [ABSTRACT FROM AUTHOR]