Advanced Materials Research Vols. 986-987

Abstract: Dynamic voltage can be described by two parts in time domain, sinusoidal steady state component and dynamic state component. The latter reflects the effect of the system’s characteristic root, and is also called decaying DC component. Decaying exponential signal has continuous spectrum, and this characteristic has a bad effect on the accuracy of phase angle’s measurement, therefore the idea of filtering the decaying exponential signal was proposed. To verify the possibility of this proposal, this paper analyzes the frequency formation of dynamic voltage signal mathematically, and points out that at the frequency of the sinusoidal component, measured voltage signal’s time domain description is the superposition of two sinusoidal signals with the same frequency, different phase angles and different amplitudes. This is the reason for the deviation between the measured voltage angle and the theoretical phase angle. The deviation angle not only shows the combined action of steady component and dynamic component, but also illustrates that the decaying exponential signal cannot be filtered out.

Abstract: For today’s coal mining enterprises, the mining production environment is very harsh and sometimes there are electric leakages in the automatic production equipment which cause a great impact on the stability of coal production. This paper proposes an electric leakage fault intelligent detection model. The intelligent method can fix the electric leakage faults on time which is an important prerequisite to ensure mine production stable and secure. The experimental results show that the model can effectively detect hardware failures and leakage.

Abstract: With the development of offshore oil and gas field enters into deep water constantly, subsea production system has become the main development mode in deep water development. Pipeline End Termination (PLET) is common facilities in subsea production system and is used to provide subsea tieback interface. An embedded type PLET has been adopted in Panyu 35-1/35-2 Gas field with the water depth of 194 to 338 m. Factory Accept Test (FAT) is very important for the subsea production facilities, and the references is very limited due to technical security. This paper in detail states the flow chart, master equipment, purpose and precautions for each test of FAT for PLET, which collects great technology for the development of subsea production system.

Abstract: Measuring grounding resistance is the only basis to judge the grounding of electrical equipment is good or not. Aim at the trouble on retracting and releasing of the current lead wire and voltage lead wire;the insecure connection Lead wire and grounding resistance tramegger、grounding crooked chisel and so on;The hectic trouble such as placing or picking the grounding resistance testing equipment, we developed the integrational measurement device of grounding resistance. It mainly introduces the structure and design principle of the device, and provides the related technical essentials. Combined with the actual application,and demonstrates its convenience and flexibility by the force of contrast; Through the case analysis, fully demonstrates the device is feasible、creative and rationality.

Abstract: Videogrammetric measurement is a research focus for the organizations of wind tunnel test because of its no special requirements on the test model, its key techniques for the vibration environment of the high speed wind tunnel are introduced by this paper, such as the solution of exterior parameters with big-angle large overlap, the algorithm of image processing for extracting marked point, the method of camera calibration and wave-front distortion field measurement. The great requirements and application prospects of videogrammetry in wind tunnel fine testing have been demonstrated by several practice experiments, including to measure test model’s angle of attack, dynamic deformations and wave-front distortion field in high speed wind tunnels whose test section size is 2 meters.

Abstract: A windowed DFT method is proposed for power system frequency measurement involving amplitude modulation. First, an error analysis of conventional DFT based method considering amplitude modulation is given. Second, a noval a window DFT function is proposed method to eliminate these errors is given based on the relation among three consecutive DFT values. Due to its high precision and low required processing effort, the proposed algorithm is a good candidate for online frequency measurement.

Abstract: Analyzing the active power loss of reactive power compensation device under normal reactive power output status and its influence factors and metering the active power loss of the reactor in the 500kV substation and the capacitor in the 220kV substation, concluding that the active power meter had the influencing factors of forward and reverse active and putting forward the assessment requirements for the running reactive power compensation device by analyzing the site calibration data of metering device.

Abstract: Methods presented in this paper evaluate the on-line DGA results and provide specific on-line DGA limit values. For on-line equipment monitoring transformer condition, a method to calculate specific detecting intervals according to the evaluation of on-line DGA results is proposed. An example to calculate detecting intervals is demonstrated using the field test data acquired by on-line equipment for transformer condition-monitoring service.

Abstract: The landslide and debris flow investigation area for Danba ~ Kangding 500 kv double-circuit transmission line route selection is within Ganzi in Tibetan autonomous prefecture, with the area of about 440 km². The topography, geomorphology, geologic structure, stratum lithology, natural factors, social and economic conditions have great influences on the transmission lines route selection and its construction. For comprehensive evaluation engineering rationality and construction convenience, remote sensing technology (RS) and geographic information system (GIS) technology are taken to implement geological environment survey. With field investigation, remote sensing images interpretation method is used to determine basic characteristics of the geo-hazards.

Abstract: Based on measurement accuracy of reactive power lower than the accuracy of active power and voltage magnitude, this paper proposes an improved on-line power flow method. Through simulation, compared with the conventional power flow, this method improves the accuracy of the calculation results and also has obvious advantages on the convergence rate. Finally, the article analyzes the reasons for this situation.