Tsukasa Miyagi

Fuzzy unit commitment scheduling using absolutely stochastic simulated annealing

This paper presents a new approach to the fuzzy unit commitment problem using the absolutely stochastic simulated annealing method. In every iteration, a solution is taken with a certain probability. Typically in the simulated annealing minimization method, a higher cost feasible solution is accepted with temperature-dependent probability, but other solutions are accepted deterministically. However, in this paper, all the solutions, both higher and lower cost, are associated with acceptance probabilities, e.g., the minimum membership degree of all the fuzzy variables. Besides, the number of bits flipping is decided by the linguistic fuzzy control. Excess units with system-dependent distribution handle constraints efficiently and reduce overlooking the optimal solution. To reduce the economic load dispatch calculations, a sign bit vector is introduced with imprecise calculation of the fuzzy model as well. The proposed method is tested using the reported problem data sets. Simulation results are compared to previous reported results. Numerical results show an improvement in solution cost and time compared to the results obtained from powerful algorithms.

Absolutely Stochastic Simulated Annealing Approach to Large Scale Unit Commitment Problem

This paper presents a new approach to the unit commitment problem using the absolutely stochastic simulated annealing method. In each iteration, a solution is taken with a certain probability. Typically, in the simulated annealing minimization method, a higher cost feasible solution is accepted with temperature-dependent probability, but other solutions are accepted deterministically. That may lead to the near optimization slowly. However in this paper, all the solutions, both higher and lower cost, are associated with acceptance probabilities. Besides, the number of bits flipping is decided by an appropriate distribution. Excess units with system-dependent probability distribution handle constraints efficiently. To reduce the economic load dispatch (ELD) overhead recalculations, a sign bit vector is introduced as well. The proposed method is tested using the reported problem data sets. Simulation results for the systems up to 100 units are compared to the previous reported results. Numerical results show an improvement in solution cost and time over to the results obtained from recent powerful algorithms.

Absolute stochastic simulated annealing approach to unit commitment problem

This paper presents a new approach to unit commitment problem using absolute stochastic simulated annealing method. In every iteration, a solution is taken with a certain probability. Typically in simulated annealing method, a higher cost feasible solution is accepted with temperature dependent probability, but other solutions are accepted deterministically. That may lead to the near optimization slowly. However in this paper, all the solutions, both higher and lower cost, are associated with acceptance probabilities. Besides, number of bits flipping is decided by appropriate probability distribution. Excess units with system dependent probability distribution handle constraints efficiently. To reduce the economic load dispatch (ELD) calculation, sign bit vector is introduced as well. The proposed method is tested using the reported problem data set. Simulation results for the systems up to 100-unit are compared to previous reported results. Numerical results show an improvement in solution cost and time compared to the results obtained from recent powerful algorithms

Reduction in Pressure Rise Due to Internal Arcing Using Melting and Vaporization of Metal

Summary form only given. When an arc is ignited between the electrodes in a closed chamber, the internal pressure rises. In this paper, the reduction in the pressure rise due to internal arcing using the melting and vaporization of a de-energized metal plate was investigated experimentally. The results showed that allowing a Cu or Fe plate placed near the electrodes to be melted and vaporized by the arc, the reduction in the pressure rise increased as the amount of mass loss of the plate increased. The decrease level of the maximum pressure rise was more than 20% on average in our experiments. On the basis of these experimental results, the energy balance in the closed chamber was estimated in order to clarify the mechanism behind the reduction in the pressure rise. The dominant cause of the reduction in the pressure rise for the Cu plate was the increase in energy consumption by the melting and vaporization of the plate. For the Fe plate, it was the increase in the energy of consumption by the arc radiation.

Two-fold Simulated Annealing Approach to Unit Commitment Scheduling

Abstract This article presents a new approach to generator scheduling using two-fold simulated annealing (two-fold-SA) method that consists of decomposed-SA and coupling-SA. An initial solution is generated by priority list method. Firstly, the solution is decomposed into hourly schedules and each hourly schedule is modified by decomposed-SA using single bit flipping. If the generated new hourly schedule is better, by convention, it is accepted deterministically. A worse hourly schedule is accepted with temperature dependent SA probability. A new solution consists of these accepted hourly schedules of entire scheduling period after repair as unit-wise constraints may not be fulfilled at the time of individual hourly schedule modification. This helps to detect and modify schedules of appropriate hours. Secondly, in coupling-SA, this new solution is accepted for the next iteration if its cost is less than that of current solution. A higher cost new solution is accepted with another temperature dependent SA probability. Besides, excess units with system dependent probability distribution handle constraints efficiently, and economic load dispatch (ELD) calculations are modified to save the execution time. The proposed method is tested using the reported problem data sets. Simulation results on two cases are compared to previous reported results. Numerical results show an improvement in solution cost and time compared to the results obtained from the powerful algorithms.

Reduction in pressure rise due to internal arcing using melting and vaporization of metal

When an arc is ignited between the electrodes in a closed chamber, the internal pressure rises. In this paper, the reduction in the pressure rise due to internal arcing using the melting and vaporization of a de-energized metal plate was investigated experimentally. The results showed that allowing a Cu or Fe plate placed near the electrodes to be melted and vaporized by the arc, the reduction in the pressure rise increased as the amount of mass loss of the plate increased. The decrease level of the maximum pressure rise was more than 20% on average in our experiments. On the basis of these experimental results, the energy balance in the closed chamber was estimated in order to clarify the mechanism behind the reduction in the pressure rise. The dominant cause of the reduction in the pressure rise for the Cu plate was the increase in energy consumption by the melting and vaporization of the plate. For the Fe plate, it was the increase in the energy of consumption by the arc radiation.

Adaptive unit commitment strategy for sudden load demand change

This paper presents an adaptive unit commitment strategy with load forecasting. In general, there is a close relation between load demand and temperature. If the forecasted temperature comes off, the error margin of the load demand grows. In order to improve prediction accuracy, we forecast the load demand again after actual load does not correspond to forecasted load and actual temperature varies much with forecasted temperature. Hence, we could improve prediction accuracy of load demand. We solve unit commitment problem again for improved forecasted load to modify the day production cost of unit commitment. The simulation result with consideration of sudden load demand change show the effectiveness of the proposed method