摘要:

Microprocessor-based real-time phasor measurements, i.e. measurement of fundamental frequency, positive sequence, complex three phase voltages and currents, for enhancing on-line protection and control of interconnected electric power systems are described. The proposed research demonstrates that real-time monitoring of key system states, in the bulk power transfer problem, can be identified. It also provides the means for determining which states are the key states for that problem, and that phasor measurements can be used to improve the protection and/or control of the system. The procedure is applied to a realistic system, where such a control problem exists in practice, for confirmation of the developed technique.

ISSN:0020-7721    

DOI:10.1080/00207729008910505

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

This paper presents a sufficient graph-theoretic structural observability condition for an interconnected system, for which the properties of each unity are assumed to be known. This constitutes a decomposition method of the habitual structural criteria, from which a minimum number of outputs may be derived for observing the global system.

ISSN:0020-7721    

DOI:10.1080/00207729008910506

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

In certain circumstances a relationship between unit contribution and producing output may exist in the classical economic production quantity (EPQ) production. We discuss an EPQ model with unit contribution dependent on production output and formulate the problem as signomial geometric problem (SPG) We show that a closed form optimal solution is readily obtainable for surch an SGP problem. We also illustrate that it is simple and easy to perform certain types of post-optimality sensitivity analysis on the optimal solution. An example is worked out in detail to demonstrate the viability of using geometric programming as an efficient solution method for dealing with a certain class of inventory optimization problems.

ISSN:0020-7721    

DOI:10.1080/00207729008910507

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Cheng and Siu (1989) argued that previous economic order quantity (EOQ) related heuristics are inherently flawed, and proposed two lot-sizing heuristics that are relatively tree from EOQ considerations (EOQ-independent). Based on their computational study, it was concluded that EOQ-independent heuristics performed ‘amazingly well’ compared to optimal solutions generated by the Wagner-Whilin algorithm. This comment is a critique of the premise under which the Cheng and Siu study was conducted, illustrates the inadequacy of the test data and errors in the computational results, and compares the performance of their heuristics with two EOQ-based heuristics. It is concluded that the EOQ-independent heuristics of Cheng and Siu are far inferior to existing heuristics in the literature.

ISSN:0020-7721    

DOI:10.1080/00207729008910508

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor