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An optimal planning model of the sectional switch and tie line for the distribution network is proposed considering the tradeoff between the system reliability and economy. First, the fault incidence matrices are established for the distribution network, and the explicit analytical expression of the system reliability index is realized by the algebraic operation of the fault incidence matrices and fault parameter vectors. Then, the 0–1 integer quadratically constrained optimization model is established for the sectional switch configuration considering the capacity constraint of the tie line. Finally, the sectional switches and tie lines are optimized jointly to ensure the economic investment and maximize the system reliability. The distribution network in Taiwan Power Company is used to verify the applicability of the proposed optimization method. Compared with the intelligent optimization algorithm, the mathematical programming method in this paper can always find the global optimal switch configuration quickly. In addition, the influence of the tie line capacity constraints on the sectional switch configuration is also considered, which can provide practical reference for the power network planners in the optimization design of the distribution network. [ABSTRACT FROM AUTHOR]

To enhance the cost effectiveness of the distribution automation system (DAS), this paper proposes the immune algorithm (IA) to derive the optimal placement of switching devices by minimizing the total cost of customer service outage and investment cost of line switches. The reliability index of each service zone defined by the boundary switches is derived to solve the expected energy not served due to fault contingency, and the customer interruption cost is then determined according to the customer type and power consumption within the service zone. To demonstrate the effectiveness of proposed IA methodology to solve the optimal placement of line switches, a practical distribution system of Taiwan Power Company (Taipower) is selected for computer simulation to explore the cost benefit of line switch placement for DAS. [ABSTRACT FROM AUTHOR]

This paper proposes an alternative data envelopment analysis method to explore the efficiency, the resource allocation, and the benchmarks of the electricity distribution districts (EDD5) of Taiwan Power Company in 2003. Several empirical results are shown: 1) the EDDs covering the high-tech industry park are more efficient, on average, than ones involved in the nonhigh-tech industry park; 2) the EDDs located in urban areas outperform those located in rural areas; 3) the large-sized EDDs generally are more able to integrate their resources and to operate efficiently; 4) the benchmark-share measure shows that while small-size efficient EDDs can easily become benchmarks, large-size efficient EDDs are deemed as competitive niche players; and finally, 5) the effect on these EDDs merging their activities should be investigated to explore the possibility of increasing competitive advantage in the future. [ABSTRACT FROM AUTHOR]

Among the ancillary services, a great number of cost allocation strategies have been broadly developed in the deregulated environment. Generally, the utilization of such services can be determined by directly evaluating the actual amount of the usage or by indirectly analyzing the fair/reasonable contribution/attribution to the market participants. In the case of the primary frequency regulation (PFR) service, which is operated by the participating generating units to maintain the real-time balance between the generation and load, the discussion of the PFR service attributed to the load side has still received relatively little attention. In this paper, a new strategy of the cost allocation of the PFR service from the customer side is proposed. Two main factors, the load fluctuation and the frequent demand change, are considered to figure out the PFR reaction relating to the different substations. The design of a scheme for determining the cost allocation index of the PFR service can be applied to the presently exiting power market. In addition, the actually load series recorded from the extra-high voltage (EHV) substations of the Taipower system located in northern, central, and southern Taiwan are meticulously analyzed and utilized to verify the feasibility and practicability of cost allocation. [ABSTRACT FROM AUTHOR]

In this paper, an expert system is designed to derive the rephasing strategy of laterals and distribution transformers to enhance three-phase balancing of distribution systems. The heuristic rules adopted by distribution engineers are incorporated in the knowledge base of the expert system in the problem-solving process. The neutral current reduction algorithm is developed to support the inference engine to derive the rephasing strategy to reduce the neutral current of distribution feeder so that the tripping of over-current relay can be prevented and the customer service interruption cost and labor cost to execute the rephasing strategy can be justified by the power loss reduction obtained. To demonstrate the effectiveness of the proposed expert system to enhance three-phase balance, a practical distribution feeder in Taiwan Power Company (Taipower) is selected for computer simulation. By minimizing the objective function subjected to the rephasing rules, the rephasing strategy has been derived to identify the laterals and distribution transformers for phasing adjustment. After executing the proposed rephasing strategy by Taipower engineers, the phase currents and neutral current of test feeder has been collected by the SCADA system to verify the reduction of neutral current. The power loss reduction obtained by three-phase balancing has been solved by three-phase load flow analysis, which is then used to justify the customer service interruption cost and labor cost for rephasing of test feeder. [ABSTRACT FROM AUTHOR]

This paper describes the application of proposed under-frequency load shedding scheme with dynamic D-factors, i.e., load frequency and voltage dependent coefficients, of various dynamic load models to Taiwan power system. The load models adopted are 1) a single-motor dynamic model, 2) a two motor (one small and one large) dynamic model, and 3) a composite (static and dynamic) model. First, the dynamic D -factor values of these load models are determined by the actual analytical approach employed in Taiwan power system. Then, a single-machine model representing a multi-machine power system is utilized for validating the proposed load shedding scheme with derived dynamic D-factor values. Finally, time simulation results of load shedding applied to various load models are compared with field measurement data, which are obtained from Taiwan power system in the case of three-phase short circuit fault, to evaluate the effects of different load models on the proposed load shedding scheme, based on the restoration of system frequency. [ABSTRACT FROM AUTHOR]

An emergency dispatch strategy (EDS) is proposed as a power system operational support tool following a transformer malfunction. First, a revised model based on IEEE C57.91 provides a method to calculate the remaining life of a transformer from the data of current load and elapsed life. Second, the life function and the constraints of transformers and the system are constructed to formulate the dispatch model. Finally, a realistic test case based on the Taiwan power system is used to demonstrate the practical applications of the EDS method. The results, when compared with those obtained using the traditional balance loads method (BLM), indicate that the EDS method is beneficial because power operators would have more time to replace a damaged transformer and successfully defer a power outage. [ABSTRACT FROM AUTHOR]

This paper derives two fuzzy financial profitability models, namely, a least cost solution model and a cost-benefit analysis model, to evaluate the fuzzy financial profitability of load management alternatives. A straightforward vertex parameters' fuzzy mathematics operation using the function principle is derived as an alternative to the traditional extension principle and is applied to evaluate a number of different financial decision indexes. Compared to the extension principle, the function principle is simple to implement and is conceptually straightforward. The geometric moments of the fuzzy financial indexes are established in order to determine their relative ranking as part of a decision-making process. The performances of the proposed fuzzy financial models are verified by considering their application to two practical load management programs in Taiwan, namely, a cooling energy storage air conditioner and a cogeneration project. These investigations not only confirm that the results of the fuzzy financial models are consistent with those of the conventional crisp models but also demonstrate that the proposed models are more flexible, intelligent, and computationally efficient compared to the extension principle fuzzy mathematics approach. The developed models represent readily implemented possibility analysis tools for use in the arena of uncertain financial decision-making. [ABSTRACT FROM AUTHOR]

The coevolutionary algorithm (CEA) based on the Lagrangian method is proposed for hydrothermal generation scheduling. The main purpose of hydrothermal generation scheduling is to minimize the overall operation cost and the constraints satisfied by scheduling the power outputs of all hydro and thermal units under study periods, given electrical load and limited water re- source. In the proposed method, a genetic algorithm is successfully incorporated into the Lagrangian method. The genetic algorithm searches out the optimum using multiple-path techniques and possesses the ability to deal with continuous and discrete variables. Regardless of the objective function characteristic the genetic algorithm does not have to modify the design rules and possesses the ability to go over local solutions toward the global optimal solution. The genetic algorithm can improve the disadvantages of the traditional Lagrangian method, which updates Lagrange multipliers according to the degree of system constraint violation by the gradient algorithm, and further searches out the global optimal solution. The developed algorithm is illustrated and tested on a practical Taiwan power system. Numerical results show that the proposed CEA based on the Lagrangian method is a very effective method for searching out the global optimal solution. [ABSTRACT FROM AUTHOR]

Deals with a study which investigated the impact of load models on an unstable low frequency oscillation damping through the eigenvalue analysis approach tested in the power system of Taiwan. Kinds of system-wide load models; Description of the study system; Application of power system stabilizers.

Restructuring of power system stresses the need for economic and reliable generation of power. Therefore generating units should be committed considering fuel cost and reliability level of the system. This necessitates the need for multi-objectives to be met in a unit commitment problem (UCP). Since the above objectives are conflicting in nature, a novel methodology employing optimal deviation based firefly algorithm tuned fuzzy membership function is applied to multi-objective unit commitment problem (MOUCP). The ON/OFF status of the generating units is obtained by binary coded FF whereas the sub-problem economic dispatch (ED) is obtained by real coded FF. Here the conflicting functions are formulated as a single objective function using fuzzy weighted optimal deviation. The fuzzy membership design variables are tuned using real coded FF; thereby the requirement of expertise for setting these variables are eliminated. The proposed methodology is validated on 100-unit system, IEEE RTS 24-bus system, IEEE 118-bus system and a practical Taiwan Power (Taipower) 38-unit system over a 24-h period. Effective strategy on scheduling spinning reserve is demonstrated by comparing its performance with other methods reported in the literature. [ABSTRACT FROM PUBLISHER]

Introduces an application program based on an automated mapping /facilities management geographic information system (AM/FM/GIS) to provide information expectation, load forecasting and power flow calculation capability in electric power distribution systems in Taiwan. Defects of the transformer load management (TLM) program based on AM/FM/GIS used by Taipower; Measures done to improve the defects of the TLM program.

Focuses on a study that applied Petri nets to enhance the decision-making process of the feeder switching operation using artificial intelligent approaches in solving the feeder overload and fault contingency. Details on the Petri nets inference mechanism; Application of the method to one of the distribution systems of the Taiwan Power Company; Results and discussion.

Presents information on a data envelopment analysis (DEA) study which evaluated the relative efficiencies of several electricity distribution districts of the Taiwan Power Company (TPC) in Taiwan. Foundations of DEA; Input and output data of TPC electricity distribution districts; Reorganization of electricity distribution districts.

Presents a study which proposed an approach based on neural network for the hydroelectric generation scheduling with pumped-storage units at Taiwan power system. Purpose of hydroelectric generation scheduling; Description of the problem; Overview of the neural network approach; Hydroelectric generation scheduling using noise annealing neural network.

This letter presents a simple criterion for reviewing balanced three-phase fault and unbalanced ground-fault current using the ratio of zero sequence impedance to positive sequence impedance as seen from the fault location, which can be employed to enhance the power system design and protection. The method has been verified by real power systems in Taiwan with satisfactory results. [ABSTRACT FROM AUTHOR]