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Yang G.,Shanghai JiaoTong University | Tai N.,Shanghai JiaoTong University | Zheng X.,Shanghai JiaoTong University | Wang C.,Henan Kaifeng Power Supply Company
Australian Journal of Electrical and Electronics Engineering

A new fault location algorithm for three-terminal high or extra-high voltage transmission lines is presented and validated. The algorithm is based on the transmission line model with lumped parameters considering the distributed capacitance of lines. Only the sequence component of fault voltage is used in fault location to avoid the influence of saturated current transformer. In location formulas, positive sequence components are used for symmetric faults and negative sequence components are used for non-symmetric faults. The schemes for the following three different conditions of three-terminal lines are discussed in detail: single-circuit line with T-connection networks, single-circuit line to double-circuit line with T-connection networks, doublecircuit line with T-connection networks. A new faulted branch selection method is proposed. The hypothetical fault distance of each branch is calculated and compared to accurately determine which branch is faulty. ATP simulation indicates that the location precision is satisfied no matter the measurements are synchronised or unsynchronised at three terminals. A quantitative comparison with the other known algorithms reveals that the presented new algorithm has higher location accuracy and can judge fault branch more accurately. © Institution of Engineers Australia, 2014. Source

Huang Y.-F.,North China Electrical Power University | Liu W.-X.,North China Electrical Power University | Sheng J.,North China Electrical Power University | Zhang X.,North China Electrical Power University | Niu W.-P.,Henan Kaifeng Power Supply Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control

A general reliability evaluation algorithm for complex medium voltage distribution networks(MVDNs) is proposed, in which each feeder is a basic unit and without simplifying the network equivalent, the depth-first search algorithm and breadth-first search algorithm are used to search each feeder in topologies. Then circuit breakers oriented first-class zone based on the same influences by the failure and isolating switches oriented feeder second-class which is also the minimum zone based on causing the same failure impact are formed. System's normally power supply area, system's operational recovery of power supply area and system's unoperational recovery of power supply area can be formed by each at one time. Based on the AutoCAD visualization platform, and using ObjectARX secondary development technique and large-scale database, the paper has completed the design and implementation of reliability evaluation module under the graphical interface applications. The module has been tested on the practical MVDNs to calculate the system reliability index quickly and find out the weak link, which verifies the effectiveness and the practicability of the proposed methods and applications in practical engineering. Source

Gao F.-L.,Henan Kaifeng Power Supply Company | Zhang P.,Henan Kaifeng Power Supply Company | Sai X.,Kaifeng Jingyu Power Company | Sai L.,Kaifeng Jingyu Power Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control

A parameter self-adaptive differential evolution algorithm(PSADE)for locating and sizing distribution substations is proposed. According to the function of mutation weighting factor and crossover factor on differential evolution(DE), the key factor to improve the performance is on the equilibrium between exploration of the entire search space and exploitation of the space already visited. The separate parameters for each individuals and the corresponding updating scheme of evolution procedure are designed. On the problem formulation of substation locating and sizing, the uncertainty of load forecasting result is considered. The fitness function is formulated based on fuzzy expected value model of investment costs. From the testing results of two well known benchmark problems and two practical substation planning areas, it is observed that the proposed PSADE is more efficient than DE and PSO, and the planning results are economical and applicable. Source

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