This paper is to investigate the load transfer function of distribution automation project to be implemented in Taipower distribution system During the summer peak season, the main transformers of distribution substat...
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(纸本)0780363388
This paper is to investigate the load transfer function of distribution automation project to be implemented in Taipower distribution system During the summer peak season, the main transformers of distribution substations in Taipower become over loaded due to the usage of air conditioners in the commercial and residential sections. The non-interruptible load transfer among distribution main transformers has to be executed for power reallocation to solve the problem. In this paper, the hourly loading of each service zone in the distribution system is determined by the load composition of the customers served within the service zone. The hourly current flows of line switches are derived by simplified three-phase load now analysis. Applying the binary integer programming (BIP) to solve the distribution system reconfiguration so that the load transfer among main transformers can be obtained derives the optimal switching operation. With the execution of the load transfer for Taipower distribution system by the proposed BIP method, the load balance among distribution main transformers during the summer peak hours is obtained. A Taipower distribution system with six feeders is selected for computer simulation to demonstrate the effectiveness of the proposed methodology.
Project selection is a major problem in managerial decision making. In this study, a deterministic model that schedules project starts is formulated as a binaryinteger program. This model is applicable in various set...
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Project selection is a major problem in managerial decision making. In this study, a deterministic model that schedules project starts is formulated as a binaryinteger program. This model is applicable in various settings such as selection of engineering projects in corporate planning, or in other planning environments in which the candidate projects are interdependent. The results of experimental runs with representative data show that the binaryinteger model can provide the required solutions in a very reasonable amount of time.
This paper is to investigate the optimal switching problem of distribution systems by considering the customer load characteristics and the effect of temperature change to the customer loading. The load survey is appl...
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This paper is to investigate the optimal switching problem of distribution systems by considering the customer load characteristics and the effect of temperature change to the customer loading. The load survey is applied to derive the typical load patterns of residential, commercial, and industrial customer classes. The power consumption of sample test customers and weather information are used to solve the hourly temperature sensitivity of power consumption for each customer class. All the customers served by each distribution transformer are identified and their monthly energy consumption is retrieved from the customer information system in Taipower. The hourly loading of each service zone and its change due to temperature rise are obtained based on the customer load consumption and its temperature sensitivity. By performing the connectivity trace to find the feeder configuration and executing the three-phase load flow analysis, the hourly current loading of line switches, distribution feeders, and main transformers in substations are solved. The binary integer programming is then applied to determine the temperature adaptive optimal switching operation for noninterruptible load transfer among distribution feeders and main transformers.
Let B-n = {-1,1}(n) denote the vertices of the n-dimensional cube. Let U(m) be a random m-element subset of B-n and suppose w is an element of B-n is a vertex closest to the centroid of U(m). Using a large deviation, ...
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Let B-n = {-1,1}(n) denote the vertices of the n-dimensional cube. Let U(m) be a random m-element subset of B-n and suppose w is an element of B-n is a vertex closest to the centroid of U(m). Using a large deviation, multivariate local limit theorem due to Richter, we show that n/pi log n is a threshold function for the property that the convex hull of U(m) is contained in the positive half-space determined by w. The decision problem considered here is an instance of binary integer programming, and the algorithm selecting w as the vertex closest to the centroid of U(m) has been previously dubbed majority rule in the context of learning binary weights for a perceptron. (C) 1998 John Wiley & Sons, Inc.
The dynamic nature of an operating environment, such as machine utilization and breakdown frequency results in changing preventive maintenance (PM) needs for manufacturing equipment. In this paper, we present an appro...
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The dynamic nature of an operating environment, such as machine utilization and breakdown frequency results in changing preventive maintenance (PM) needs for manufacturing equipment. In this paper, we present an approach to generate an adaptive PM schedule which maximizes the net savings from PM subject to workforce constraints. The approach consists of two components: (a) task prioritization based on a multi-legit regression model for each type of PM task, and (b) task rescheduling based on a binary integer programming (BIP) model with constraints on single-skilled and multi-skilled workforce availability. The task prioritization component develops a multi-legit regression for machine failure probability associated with each type of PM task at the beginning of the year, using historical data on machine utilization, PM, and machine breakdowns. At the start of each PM time-bucket (e.g., a month), we use the updated machine failure probability for each candidate PM task to compute its current contribution to net PM savings, which indicates its current priority. The task rescheduling BIP model incorporates the priorities in selecting tasks for the current bucket to maximize PM effectiveness subject to workforce availability, yielding an adaptive and effective PM schedule for each time-bucket of the master PM schedule. We examine the effect of using multi-skilled workforce on the overall PM effectiveness, and also provide an illustration from a newspaper publishing environment to explain the use of the approach. We have developed four heuristic algorithms to yield good solutions to large scale versions of this scheduling problem. The heuristics perform extremely well, and the best heuristic solution is within 1.4% of optimality on an average.
Harmonic update is a randomized on-line algorithm which, given a random rn-set of vertices U(m) subset of or equal to {-1, 1}(n) in the n-dimensional cube, generates a random vertex w is an element of {-1, 1}(n) as a ...
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Harmonic update is a randomized on-line algorithm which, given a random rn-set of vertices U(m) subset of or equal to {-1, 1}(n) in the n-dimensional cube, generates a random vertex w is an element of {-1, 1}(n) as a putative solution to the system of linear inequalities: Sigma(i=1)(n) w(i)u(i) greater than or equal to 0 for each u is an element of U(m). Using tools from large deviation multivariate normal approximation and Poisson approximation, we show that root n/root log n is a threshold function for the property that the vertex w generated by harmonic update has positive inner product with each vertex in U(m). More explicitly, let P(n, rn) denote the probability that Sigma(i=1)(n) w(i)u(i) greater than or equal to 0 for each u is an element of U(m). Then, as n --> infinity, P(n, m) --> 0 or 1 according to whether m = m(n) varies with n such that >> root n/root log n or m << root n/root log n, respectively. The analysis also exposes the fine structure of the threshold function.
The purpose of the paper is to find the optimal criteria for interfeeder switching in a distribution system during emergency conditions. A feeder in a distribution system usually has several interfeeder switches prope...
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The purpose of the paper is to find the optimal criteria for interfeeder switching in a distribution system during emergency conditions. A feeder in a distribution system usually has several interfeeder switches properly located along the feeder to link with other feeders. Under emergency conditions, such as when faults occur on the distribution feeder, these switches are operated interdependently to minimise the loss of load and to prevent overload or unbalance power flow on the distribution feeders. In the paper, a computer program is developed to find the optimal switching algorithm. The cost function of the switching operation is defined, and the bipartite graph network is constructed according to the configuration of the distribution system. The binary integer programming (BIP) technique is used to minimise the objective function which is set up based on the relief of feeder overloading and unbalance. A distribution system comprising several substations in the Taiwan Power Company is selected for the simulation of optimal switching and the accuracy and efficiency of this program are verified.
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