Incremental transmission loss allocation under pool dispatch

Incremental transmission loss analysis has been used for decades, but recent interest in its application to loss allocation calls for new in-depth results. This paper demonstrates that, for incremental methods to be applied correctly in loss allocation, it is first necessary to specify the load distribution and loss supply strategies. Incremental loss allocation among bus power injections is shown to be arbitrary and, therefore, open to challenge as discriminatory. Loss allocation is possible among incremental loads and/or generators, but the proportion of the total losses assigned to either one is arbitrary. Unique, nonarbitrary incremental loss allocations are however possible among the "equivalent" incremental bilateral exchanges between generators and loads. From these basic components it is possible then to calculate the allocation among generators or loads in any specified proportion. The main results, although developed initially for small increments, are extended to large variations. Finally, a general incremental loss allocation algorithm is developed and tested     

Introducing the Planar Laser-Induced Fluorescence Technique (PLIF) to Measure Mixing Time in Gas-Stirred Ladles

Metallurgical and Materials Transactions B - The planar laser-induced fluorescence (PLIF) technique was implemented to measure mixing time in a 1/17 water model of a 200-ton ladle furnace. The...     

$m-k$ Robust Observability in State Estimation

This paper provides a technique to determine the minimum required measurement set to ensure observability in state estimation even if any meters fail. The technique relies on solving a nonlinear integer programming problem. The proposed procedure is illustrated through a simple example and three case studies based on the IEEE Test Systems. Conclusions are finally drawn.     

Short-term hydro-thermal coordination by Lagrangian relaxation:solution of the dual problem

This paper addresses the short-term hydrothermal coordination problem. This problem is large-scale, combinatorial and nonlinear. It is usually solved using a Lagrangian relaxation approach. In the framework of the Lagrangian relaxation, this paper provides a novel, nonoscillating and efficient multiplier updating procedure. This procedure advantageously compares with previously reported procedures such us subgradient and bundle methods. A realistic large-scale case study is used to illustrate the behavior of the proposed procedure     

Binary-arithmetic approach to observability checking in state estimation

An efficient and robust technique for observability checking in power system state estimation based on Gaussian elimination and binary arithmetic is provided. Since the proposed technique uses binary arithmetic, no rounding error, numerical instability or zero identification problems occur. In some cases, the technique may not identify all observable state variables, requiring an additional numerical analysis over a matrix of dimension that is highly reduced. An illustrative example of small size and a realistic case study are used to demonstrate the features of the proposed technique. Adequate conclusions are finally drawn.     

A comparison of interior-point codes for medium-term hydro-thermalcoordination

This paper studies the performance of newly developed and under development interior-point optimization codes as applied to the solution of medium-term hydro-thermal coordination (MTHTC) problems. We compare commercial and research codes, and their main advantages and drawbacks are pointed out. The codes that we study are: CPLEX 3.0-barrier (the latest version of OB1 by Lustig), HOPDM by Gondzio, LOQO by Vanderbei, PCx by Mehrotra's group, LIPSOL by Zhang, and LPA1 (a code being developed by the authors). All codes have been tested on the Spanish hydrothermal system     

Optimal price and quantity determination for retail electric power contracts

Considering the viewpoint of a retailer, this paper analyzes the problem of setting up contracts on both the supplier and end-user sides to maximize profits while maintaining an acceptable level of settlement risk. The proposed stochastic optimization model can assist retailers with these efforts and guide them in their contractual arrangements. A realistic example illustrates the capabilities of the methodology proposed.     

ARIMA models to predict next-day electricity prices

Price forecasting is becoming increasingly relevant to producers and consumers in the new competitive electric power markets. Both for spot markets and long-term contracts, price forecasts are necessary to develop bidding strategies or negotiation skills in order to maximize benefit. This paper provides a method to predict next-day electricity prices based on the ARIMA methodology. ARIMA techniques are used to analyze time series and, in the past, have been mainly used for load forecasting, due to their accuracy and mathematical soundness. A detailed explanation of the aforementioned ARIMA models and results from mainland Spain and Californian markets are presented.