Advanced Materials Research Vols. 1044-1045

Abstract: Stone coal and two kinds of biomass were respectively mixed and studied during pyrolysis by using thermogravimetric analyzer. The results showed that the main pyrolysis peak temperature of stone coal is the lowest under the mixing ratio of 3:7 during the pyrolysis process. Because of the high content of alkali, corn stalk has better promotion for the coal pyrolysis compared to sawdust.

Abstract: The distance relays of transmission lines find limitations in the presence of series compensated capacitor. One of them is the distance relay setting issue, in which either over-reach problem or under-reach problem may occur. To deal with this issue, a differential equation based adaptive distance relaying setting method for series compensated line is proposed. As for it do not need to identify whether SC/MOV is in fault loop, not need to know the parameters and the operating states of SC/MOV/GAP, and furthermore, it can be realized without the iterative calculation, it is very suitable to be used for the distance relaying adaptive setting of series compensated line. Simple simulation results certificate the proposed adaptive setting method.

Abstract: Water environment assessment is a basic and important work of water resources protection. We set up a fuzzy comprehensive evaluation of water environment based on fuzzy theory and prediction method in this paper. The comprehensive assessment of water environmental quality relates to complicated phenomena and interaction of multi-factor of evaluation. There are plenty of fuzzy phenomena and fuzzy concepts, therefore, make quantitative processing by the comprehensive evaluation method of fuzzy is a good choice to get good results.

Abstract: Research on power system fault diagnosis and method of relay protection action require the complete primary equipment topological structure of the grid. This article propose an evaluation method based on power network topology structure, which is easily implemented and it can assess the performance of breakers and protections in an entire power system. Considering the missing or error information, a protection motion capability analysis method based on genetic algorithm is proposed on the basis on that method. The simulation results on IEEE three-machine nine-bus system show that the algorithm is capable of discriminating the fault fast and accurately, and has excellent fault-tolerance capability.Keywords: Relay Protection; evaluation of action; Genetic Algorithm; fault-tolerance capability

Abstract: Based on the separated production scheme of perforated horizontal well, the production is closely related to the number, length and location of horizontal intervals. New reservoir / wellbore coupling models were modeled which included two boundaries: closed boundary and constant pressure boundary. For these coupling models, two new optimization models were modeled, which took the production as the objective function and took the length and location of horizontal intervals as the optimization variables. Then the numerical calculation models were proposed by using the Gauss-Laguerre quadrature formula. Applying the genetic algorithm and writing the numerical stimulation software, the optimized schemes with 2 segments, 3 segments and 4 segments for planning intervals of the perforated horizontal wells were presented. By comparing the optimized schemes, we can see that the horizontal well production was not infinite increasing with the length of horizontal intervals, but only in the suitable length of horizontal intervals to maintain high production. And it is not the more segments the higher production. For the perforated horizontal well in closed reservoir, the production was the highest based on the optimized schemes with 3 segments.

Abstract: Grid infrastructure is vulnerable to damage or breakdown by various of natural disasters and man-made disasters to cause a loss of all or parts of the function of power system. In this paper, through the analysis of various factors affecting the hub substation physical vulnerability of hub substation such as human factors, natural disasters and equipment factors, calculate and classifiy the influence degree of each factor on the physical vulnerability. Put forward a series of suitable vulnerability assessment method for China's national hub substation. What’s more, take a specific hub substation for example to verify the assessment methods that provided a basis for safe operation of power facilities and disasters prevention.

Abstract: The parallel capacitors are the most important reactive power compensation devices in power system, while the power system harmonic pollution is becoming increasingly serious in recent years, the accident that caused capacitors fault and damage by overload harmonic always happened. Based on this background and summary of the existing research results, thermal effect and performance index of capacitors are introduced, and analyzed the mechanism of interaction between harmonic and capacitor, then the effect and harm of running capacitor under harmonic conditions are elaborated, finally summarized the feasible measures for harmonic suppression and protection of capacitor devices.

Abstract: It is the direction of the future development of the electricity market to assess power quality and determine the tariff in accordance with the power quality. This paper established attribute recognition theoretical model, and determined the weight of each evaluation index of power quality based on Analytic Hierarchy Process (AHP) algorithm, and proposed the comprehensive assessment of power quality based on attribute recognition theory and AHP algorithm. Even considering various impact factors of steady state and transient state, this algorithm is able to avoid the subjectivity affecting the evaluation results for power assessment index weight, ensuring the fairness of the assessment. The results show that this algorithm is much more effective than the fuzzy comprehensive evaluation method in differentiating the level of power quality, and thus to ensure the fairness of evaluation results.

Abstract: This paper is for real-time monitoring sag problem of overhead lines, modeling two kinds of models with the state equation of catenary line and parabolic method, which are based on fiber grating sensing technology and take advantage of the conversion relationship of overhead line length between different states. The performance comparative analysis is carried out between the two models and currently relatively mature angle method. Experimental measuring results show that under the same conditions, the monitoring results of two models are very near to the monitoring results of angle method. But relatively speaking, monitoring results of the catenary model are more accurate. The accuracy of models can meet the project requirements and two models both can monitor overhead lines sag effectively in real time.

Abstract: This paper presents the unit commitment of main transformers to meet the service reliability criterion in distribution substations by considering the growth of photovoltaic (PV) installation with the probabilistic power generation in the service area. The historical data of solar irradiation over one year period are collected to derive the annual duration curve of solar energy to derive the probabilistic distribution of PV power generation. All PV power systems of each study year are considered as an equivalent virtual main transformer with probabilistic capacity. By the integration of probabilistic PV power generation model and the risk model of main transformer outage, the loss of load expectation (LOLE) of the distribution substation is analyzed according to the annual growth of customer loading and PV penetration level. When the LOLE is less than the service reliability criterion, one new unit of main transformer has to be added to improve system reliability.