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Abstract: Taiwan is a high energy-importing nation with approximately 98% of our energy supplied by imported fuels in 2004. The energy conservation and/or energy efficiency improvement is becoming vital energy issues in the country. In this regard, cogeneration system or combined heat and power system used for the utilization of waste heat from energy and industrial sectors is thus becoming attractive due to the energy, economic and environmental policies for pursuing stable electricity supply, sustainable development and environmental pollution mitigation in Taiwan. The objective of this paper is to present an analysis of cogeneration system utilized as sustainable energy in the industrial sector in Taiwan. The description in the paper is thus summarized on an analysis of electricity supply/consumption and its sources from cogeneration system during the past two decades (1984–2004) and then centered on new/revised promotion legislation/regulations especially concerning cogeneration system in the measures of environmental protection and economic/financial incentives. Finally, we preliminarily present the results of environmental benefit analysis in the greenhouse gases reduction. Based on the data in 2004, it was found that the reduction benefits of carbon dioxide and nitrous oxide were estimated to achieve 3.488×107 and 650 metric tones, respectively. [Copyright &y& Elsevier]

This paper presents the protective relay settings of tie line tripping and design of load-shedding scheme for an integrated steelmaking industrial power system to ensure system stability after a severe fault contingency on an external utility power network. The transient stability analysis of the industrial power system with the equivalent external Taipower system has been executed for an actual fault contingency in 2005. The mathematical models of 13 cogeneration units in the plant and several large generators of a nearby Taipower thermal plant are included in the computer simulation to solve the system transient response for the fault contingency to verify the accuracy of the models used. To prevent tripping of critical loads due to an external fault contingency, the undervoltage and under/overfrequency relays with proper settings are applied for the tripping of external and internal tie lines. To restore system stability of the industrial power system for the islanding operation after tie line tripping, load shedding is designed to disconnect a proper amount of noncritical loads by considering the governor response and protective constraints of cogeneration units. According to the transient stability analysis of the industrial power system with the proposed protective relay settings and load-shedding scheme, it is found that the voltage sag and oscillation problem caused by fault contingency in the external Taipower system can be mitigated if the tie line tripping is executed in time to prevent the shutdown of critical loads and tripping of cogeneration units. [ABSTRACT FROM AUTHOR]